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The best is the enemy of the good.
Species are mortal too.
They appear, they die out. Some quickly, some slowly. Sharks are an old species. Sharks appeared 450 million years ago. Humans, two million. Homo neanderthal is gone already. How will homo sapiens do?
The Earth’s fossil record shows five mass extinctions, in which many or most species disappeared over a few months or centuries. The first four are mysterious. We don’t know for certain what caused them.
The Fifth Extinction we know about. 250 million years ago, an asteroid the size of Manhattan slammed into the Yucatan peninsula in Mexico.
The energy released was like a hundred million atom bombs. The Earth’s forests burned down. A vast tsunami swamped every coast on the planet. The Fifth Extinction was as sudden as they get.
Mass extinctions are part of the life of the planet. We are now at the end of the Sixth. It started centuries ago. We just noticed.
Species loss is now hundreds of time faster than the ‘background’ rate over the millennia. Some of this is now widely known. We have hunted lions, tigers and whales near to extinction. We have almost emptied the oceans of fish. Warming from our carbon emissions is melting the ice polar bears live on.
But the Sixth Extinction is not recent. Species loss has been accelerating for centuries. It matches the spread of humans. Species disappear as we farm and build. Where humans flourish, other species disappear.
Climate change is the closing paragraph of a story that began before we started writing.
Yeast in a warm container of nutrients consumes all the food then dies in its own waste. Any animal that sees its species double in a lifetime has cause to worry.
Of course, humans are not yeast. We’re talking about it.
But that’s about all we’re doing. There are ways to soften the end of the Sixth Extinction. Although polar bears won’t survive, there are things we could do so humans might. But we’re not doing those things. Nothing remotely like them. As a species we don’t seem to have whatever that takes.
The next decades will see species of life disappearing faster and faster. The human population will crash. What we do right now determines how soon, how far and how fast.
We’re not doing much, so expect it to get ugly. | <urn:uuid:82d26d58-3e16-4d8d-9f82-6eb5e1500534> | 2.53125 | 518 | Personal Blog | Science & Tech. | 68.99539 | 95,530,749 |
Sentencedict.com random good picture
1. The split rock is slow to fall, the gravitational force being lower and the angle of fall correspondingly sharper.
2. Weight is the gravitational force of attraction exerted on a body.
3. Try and work out the gravitational force between two objects in terms of a quantum graviton, however, and you quickly run into trouble—the answer to every calculation is infinity.
4. The sun uses brute gravitational force to achieve fusion reaction.
5. Earth's gravitational force or pull keeps us and everything else Earth from floating away to space.
6. He discovers suddenly, tellurian gravitational force is very large, let him besides cannot flicker flicker ground flies besides, also do not have even the friend a few.
7. The discovery of the repulsive, anti - gravitational force of dark energy is explained.
8. He would be torn apart by the difference between the gravitational force on his head and his feet.
9. If there is less than a certain amount, the gravitational force will be insufficient to stop a never-ending expansion.
10. This is only true in deep space when the gravitational force can be neglected.
11. Since all objects in this lecture hall and the earth fall with the constant acceleration, which is g we can write down that the gravitational force m would be m times this acceleration, g.
12. In his monumental work begun in 1666 [sentencedict.com], Newton discovered three vital facts about the gravitational force.
13. Effects of LBNP is similar to that produced by gravitational force, especially as a stress factor on the cardiovascular system as has been concerned in the area of aerospace medicine.
14. Moreover, because of their intense density, neutron stars exert strong gravitational force on their binary companion.
15. Newton's problem was to express in mathematical terms the gravitational force between different bodies.
16. Each mass subject to two forces, namely the tension of the string and the gravitational force.
17. A gibbon is better adapted than a man for life in a low gravitational force.
17. Wish you will love sentencedict.com and make progress everyday!
18. LG's DVD for example, because it is through the main bearing and the compression of the gravitational force between the magnetic disc to grip, so this problem does not exist.
19. LG's DVD for example, because it is through the main bearing and the compression of the gravitational force between the magnetic disc attached to and so this problem does not exist.
20. This is the formula for a thick vertically faulted slab with such a large throw that the downthrow side makes no contribution to the gravitational force.
21. So a lot of people objected to Newton's postulation of this gravitational force.
22. This force is made up of tire, aerodynamic and gravitational force components.
23. The paper expounds the principle and the method of measuring zenith distance for celestial positioning based on the direction of gravitational force line.
More similar words: gravitational, gravitate, capital formation, gravitas, invitation, levitation, navigational, proportional representation, computational, confrontational, malformation, centrifugal force, international relations, rationalization, nationalization, rationalisation, multinational corporation, gravity, zero gravity, aggravation, citation, rational, national, statute of limitations, imitation, agitation, rationale, rationally, capitation, sanitation. | <urn:uuid:682596cf-3de0-4c35-b1e1-b02ba3976a58> | 2.90625 | 707 | Content Listing | Science & Tech. | 40.367148 | 95,530,752 |
March 24th, 2007 06:58 EST
Gravity Measurements Help Melt Ice Mysteries
Greenland is cold and hot. It's a deep freezer storing 10 percent of Earth's ice and a subject of fevered debate. If something should melt all that ice, global sea level could rise as much as 7 meters (23 feet). Greenland and Antarctica - Earth's two biggest icehouses - are important indicators of climate change and a high priority for research, as highlighted by the newly inaugurated International Polar Year.
Just a few years ago, the world's climate scientists predicted that Greenland wouldn't have much impact at all on sea level in the coming decades. But recent measurements show that Greenland's ice cap is melting much faster than expected.
These new data come from the NASA/German Aerospace Center's Gravity Recovery and Climate Experiment (Grace). Launched in March 2002, the twin Grace satellites circle the globe using gravity to map changes in Earth's mass 500 kilometers (310 miles) below. They are providing a unique way to monitor and understand Earth's great ice sheets and glaciers.
Grace measurements have revealed that in just four years, from 2002 to 2006, Greenland lost between 150 and 250 cubic kilometers (36 to 60 cubic miles) of ice per year. One cubic kilometer is equal to about 264 billion gallons of water. That's enough melting ice to account for an increase in global sea level of as much as 0.5 millimeters (0.019 inches) per year, according to Isabella Velicogna and John Wahr of the University of Colorado, Boulder. They published their results in the scientific journal Nature last fall. Since global sea level has risen an average of three millimeters (0.1 inch) per year since 1993, Greenland's rapidly increasing contribution can't be overlooked.
"Before Grace, the change of Greenland's ice sheet was inferred by a combination of more regional radar and altimeter studies pieced together over many years, but Grace can measure changes in the weight of the ice directly and cover the entire ice sheet of Greenland every month," says Michael Watkins, Grace project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. However, as anyone who has ever been concerned about his or her weight knows, a number on a scale is just the beginning. In the five years that Grace has been flying, scientists have found ways to make the most of this new set of observations.
"Grace has a big footprint," says Watkins. "We can locate regions of greatest loss, but we can't see individual glaciers." However, Grace's spatial resolution is continually improving. In the most recent studies, he says, Grace has observed large ice losses in the southeast of Greenland, while other areas, such as the west coast, have shown losses as well.
While Greenland is losing ice, it's also acquiring some new ice through precipitation. Scientists at NASA's Goddard Space Flight Center, Greenbelt, Md., used Grace to determine that ice losses far surpass ice gains. A new way of analyzing the data allowed them to get a picture of regional changes. While snow added 60 cubic kilometers (14 cubic miles) of ice mass to Greenland's interior each year between 2003 and 2005, the low-lying coast areas of Greenland lost nearly three times as much ice - 172 cubic kilometers (41 cubic miles) - each year during the same period.
To confirm just how much of the mass Grace detects in Greenland and Antarctica is due to snow and ice, scientists also have to determine the contributions from another source, Earth's changing crust. "When Grace sees a change in polar gravity," says Watkins, "part of it is today's ice melt and part is what is called post-glacial rebound."
"A long time ago during the last ice age, this region was pushed down by even more snow and ice, and now this mantle wants to come back, or rebound," explains Erik Ivins, a JPL Earth scientist and Grace science team member.
One way to look at the problem, says Ivins, is to imagine a bathtub filling up with water from a faucet but losing water from holes in the bottom of the tub. At the same time, the bathtub may be changing shape.
Ivins and his colleagues are refining the computer models used to understand and predict post-glacial rebound. It turns out that beneath the ice sheet covering Greenland, the mantle isn't changing the shape of the “bathtub" very fast. "This tells us that the large mass changes Grace detects in the southeastern region of Greenland aren't due to post-glacial rebound," says Ivins.
As Grace celebrates its fifth birthday and begins its extended mission, "we're getting the picture into better focus," says Watkins, "and we're going to have a new wave of discoveries. Improving the post-glacial rebound model is going to help, especially in Antarctica, where post-glacial rebound has a big effect on the gravity signal. We're also going to be able to pinpoint areas of loss and better understand how the losses change from one particular year to the next. This will tell us more about the types and mechanisms of ice mass loss so we can make better predictions in the future."
While Grace provides a new and independent way to study Earth's ice sheets, it will take a combination of different tools, including laser altimeters, radar, and field studies, to sort out more clearly what's happening. "All technologies have different strengths and weaknesses," says Watkins. "Grace is the new piece. It shows us the big picture, while other measurements look at a smaller scale. We need to use them all together."
"We have to pay attention," Velicogna adds. "These ice sheets are changing much faster than we were expecting. Observations are the most powerful tool we have to know what is going on, especially when the changes - and what's causing them - are not obvious." | <urn:uuid:aa864224-c631-4b93-a536-7328268100f6> | 3.828125 | 1,213 | News Article | Science & Tech. | 52.396503 | 95,530,760 |
The Hague: Scientists in the Netherlands have unveiled the largest radiotelescope in the world, saying it was capable of detecting faint signals from almost as far
back as the Big Bang.
The LOFAR (LOw Frequency ARray) consists of 25,000 small antennas measuring between 50 centimetres and two metres across, instead of a traditional large dish, said Femke Boekhorst of the Netherlands Radioastronomy Institute.
It is based near the northeastern Dutch town of Assen, but the antennas are spread out across the rest of the Netherlands and also in Germany, Sweden, France and Britain.
"Today we have launched the biggest radiotelescope in the world. When you combine all the antennas you get a giant telescope with a diameter of about 1,000 kilometres (600
miles)," Boekhorst told yesterday.
"The observations that we will be able to make will allow
us to learn more about the origin of the universe, back to the
moment right after the Big Bang," she added.
The data gathered by the telescope will be dealt with by
a supercomputer at the university of Groningen and then
transmitted to the institute. | <urn:uuid:3dd6aa7c-14f7-4ebe-ab1b-6036ade72d4f> | 3.390625 | 249 | News Article | Science & Tech. | 39.001739 | 95,530,763 |
In the case of the Andromeda Galaxy, however, astronomers have a few tricks up their sleeves. Firstly, images from Hubble Space Telescope have unparalleled image quality as a result of the telescope's position above the atmosphere.
This image shows NASA/ESA Hubble Space Telescope images of a small part of the disc of the Andromeda Galaxy, the closest spiral galaxy to the Milky Way. Hubble’s position above the distorting effect of the atmosphere, combined with the galaxy’s relative proximity, means that the galaxy can be resolved into individual stars, rather than the cloudy white wisps usually seen in observations of galaxies. A galaxy’s disc is the area made up of its spiral arms, and the darker areas between them. After the galaxy’s central bulge, this is the densest part of a galaxy. However, these observations are made near the edge, where the star fields are noticeably less crowded. This lets us see glimpses through the galaxy into the distant background, where the more diffuse blobs of light are actually faraway galaxies. These observations were made in order to observe a wide variety of stars in Andromeda, ranging from faint main sequence stars like our own Sun, to the much brighter RR Lyrae stars, which are a type of variable star. With these measurements, astronomers can determine the chemistry and ages of the stars in each part of the Andromeda Galaxy. Credit: NASA, ESA and T.M. Brown (STScI)
Secondly, M 31 is closer to our own galaxy than any other spiral galaxy (so close that it can even be seen with the naked eye on a very dark night ). And thirdly, these observations avoid the crowded centre of the galaxy, where the stars are closest together and hardest to separate from each other.
The resulting images offer a different perspective on a spiral galaxy. Far from being an opaque, dense object, Hubble reminds us that the dominant feature of a galaxy is the huge voids between its stars. Thus, these images do not only show stars in the Andromeda Galaxy (and a handful of bright Milky Way stars that are in the foreground): they also let us see right through the galaxy, revealing far more distant galaxies in the background.
The four images in this release look superficially similar, but on closer inspection they reveal some important differences.
The two images taken in M 31's halo show the lowest density of stars. The halo is the huge and sparse sphere of stars that surrounds a galaxy. While there are relatively few stars in a galaxy's halo, studies of the rotation rate of galaxies suggest that there is a great deal of invisible dark matter.
Meanwhile, the images of stars in the Andromeda Galaxy's disc and a region known as the giant stellar stream show stars far more densely packed, largely outshining the background galaxies. The galaxy's disc includes the distinctive spiral arms (as well as dimmer and less numerous stars in the gaps between them), while the stream is a large structure which extends out from the disc, and is probably a remnant of a smaller galaxy that was absorbed by the Andromeda Galaxy in the past.
These observations were made between 2004 and 2007 to observe a wide variety of stars in Andromeda, ranging from faint main sequence stars like our own Sun, to the much brighter RR Lyrae stars, which are a type of variable star. With these measurements, astronomers can determine the chemistry and ages of the stars in each part of the Andromeda Galaxy.
The purpose of these observations also explains their exceptional depth: to gain useful data on dim, distant stars, a long series of individual exposures had to be made in each field. Together they combine to make images with a long exposure time. This has the side-effect of also revealing the faint background galaxies, which would otherwise have been invisible.
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
The Andromeda Galaxy's full diameter in the sky is actually around three degrees, six times the width of the full Moon. But the outer regions of the galaxy are much too faint to see without a telescope.
Image credit: NASA, ESA and T. M. Brown (STScI)
- Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/
Oli Usher | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
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18.07.2018 | Life Sciences
18.07.2018 | Information Technology | <urn:uuid:23573d56-de3d-48ec-93aa-2ab691ff03a1> | 3.84375 | 1,521 | Content Listing | Science & Tech. | 42.946769 | 95,530,786 |
Authors: George Rajna
Scientists from India and Portugal recreated solar turbulence on a tabletop using a high intensity ultrashort laser pulse to excite a hot, dense plasma and followed the evolution of the giant magnetic field generated by the plasma dynamics. You can't see them, but swarms of electrons are buzzing through the magnetic environment—the magnetosphere—around Earth. When NASA's Magnetospheric Multiscale—or MMS—mission was launched, the scientists knew it would answer questions fundamental to the nature of our universe—and MMS hasn't disappointed. Magnetic reconnection, a universal process that triggers solar flares and northern lights and can disrupt cell phone service and fusion experiments, occurs much faster than theory says that it should. A surprising new class of X-ray pulsating variable stars has been discovered by a team of American and Canadian astronomers led by Villanova University's Scott Engle and Edward Guinan. Late last year, an international team including researchers from the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University announced the discovery of more than 60 extremely distant quasars, nearly doubling the number known to science-and thus providing dozens of new opportunities to look deep into our universe's history. Fuzzy pulsars orbiting black holes could unmask quantum gravity. Cosmologists trying to understand how to unite the two pillars of modern science – quantum physics and gravity – have found a new way to make robust predictions about the effect of quantum fluctuations on primordial density waves, ripples in the fabric of space and time. Physicists have performed a test designed to investigate the effects of the expansion of the universe—hoping to answer questions such as "does the expansion of the universe affect laboratory experiments?", "might this expansion change the lengths of solid objects and the time measured by atomic clocks differently, in violation of Einstein's equivalence principle?", and "does spacetime have a foam-like structure that slightly changes the speed of photons over time?", an idea that could shed light on the connection between general relativity and quantum gravity.
Comments: 27 Pages.
[v1] 2017-06-30 06:28:20
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Photo credit: A.J. Plumptre/WCSNEW YORK — Scientists from the Wildlife Conservation Society (WCS) have discovered a new species of wild ginger, spicing up a wave of recent wildlife discoveries in the Kabobo Massif—a rugged, mountainous region in Democratic Republic of Congo.
The plant, Aframomum ngamikkense, is named after the four main peaks in the Kabobo massif: Ngandja, Misotshi, Kabili, and Kabobo (Ngamikka). It is confined to the higher altitudes of the forest between 1,500-2000 meters. It only occurs in small patchy regions of the massif but is locally abundant when it is found.
The recent naming of the ginger brings the number of known endemic species to the Kabobo Massif to eight: four mammals including two bats, a bird, and three plants. WCS surveys in 2007 and 2012 led to the identification of these new species which have been described in collaboration with Julian Kerbis-Peterhans of the Chicago Field Museum and Eberhard Fischer at the University of Koblenz-Landau.
There are around 50 known species of ginger scattered throughout Africa including Madagascar. The fruits are eaten by local people and wildlife including gorillas and chimpanzees. The roots are consumed to a lesser extent.
A recent expedition by Trento Science Museum and WCS to the massif may have found more new species. Genetic analyses are currently being made to assess whether this is the case. Several frog species and a pangolin are being assessed totaling at least five potentially new additional species.
Said Andrew Plumptre, WCS senior scientist: "While mountains are known to encourage speciation, it is uncommon to find so many unique species at one site, particularly when we have only made biodiversity surveys over a period of about four months."
The Kabobo Massif is one of the most biodiverse sites in Africa. To date 558 terrestrial vertebrates and 1,410 plant species have been documented. In the 1950s, Belgian scientists discovered the Prigogine's black and white colobus monkey (a subspecies of the Angolan colobus) and the Kabobo Apalis (Apalis kaboboensis) a bird only known from here. Civil war and insecurity from 1960 until 2007 prevented further work or its protection. The Kabobo Natural Reserve had its boundaries formally approved in December 2016 by the provincial governor of Tanganyika Province—a critical step in establishing and ensuring the effective protection of this important site. It adjoins the recently established Ngandja Reserve.
WCS scientists are hopeful that the recent wave of discoveries will result in both reserves being upgraded to National Reserve status, giving them a stronger legal status and protection.
Said Richard Tshombe, DRC country director: "Findings of yet more unique species demonstrate the need to make both Kabobo and Ngandja Provincial Reserves as National Reserves."
Said Deo Kujirakwinja, WCS project manager in Kabobo: "The gazettement process of the Kabobo Reserve has been made with the participation of local communities, and co-management of the reserves is improving the protection of this and many other species in Kabobo."
Kabobo and Ngandja Reserves combined with Luama Katanga Reserve protect a total of 2,683 square miles (6,951 square kilometers). This is the largest block of forest on the shores of Lake Tanganyika and provides an important watershed for this lake and protection for breeding sites for the lake's fisheries. A conservation action plan was developed for this landscape by the provincial authorities of Tanganyika and South Kivu with community leaders and WCS's technical support, and funding is being sought to implement this plan.
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Programming is becoming more and more popular all around the world.
Programming provides extreme amounts of power and flexibility, because you can take control of your computer's actual power, and you can develop your own systems and prototypes.
Python is becoming especially popular, because it's extremely user-friendly whilst still maintaining a lot of the power that other, more complex, programming languages offer. Additionally, Python has a huge community, which means all sorts of modern projects, such as Big Data, Artificial Intelligence, Machine Learning, Deep Learning, etc. have been develop for the Python community to use, which makes implementing these sorts of advanced techniques extremely easy (sometimes only 1-2 lines of code).
Employers love employees that can program, because they can go out and quickly produce results or create prototypes. The ability to program will not only open you up to new opportunities, but it will also become a better logical thinker, since computers operate on logical statements, so a good programmer has a natural thought flow that is very logical. | <urn:uuid:fd1536ee-4614-4c0c-a8ff-944f6a8d514e> | 2.765625 | 207 | Knowledge Article | Software Dev. | 21.642931 | 95,530,811 |
According to one longstanding theory, our Solar System's formation was triggered by a shock wave from an exploding supernova. The shock wave injected material from the exploding star into a neighboring cloud of dust and gas, causing it to collapse in on itself and form the Sun and its surrounding planets. New work from Carnegie's Alan Boss offers fresh evidence supporting this theory, modeling the Solar System's formation beyond the initial cloud collapse and into the intermediate stages of star formation.
An interesting component of chondrites' makeup is something called short-lived radioactive isotopes. Isotopes are versions of elements with the same number of protons, but a different number of neutrons. Sometimes, as is the case with radioactive isotopes, the number of neutrons present in the nucleus can make the isotope unstable. To gain stability, the isotope releases energetic particles, which alters its number of protons and neutrons, transmuting it into another element.
Some isotopes that existed when the Solar System formed are radioactive and have decay rates that caused them to become extinct within tens to hundreds of million years. The fact that these isotopes still existed when chondrites formed is shown by the abundances of their stable decay products--also called daughter isotopes--found in some primitive chondrites. Measuring the amount of these daughter isotopes can tell scientists when, and possibly how, the chondrites formed.
The colors represent the relative amounts of short-lived radioactive isotopes, such as iron-60, injected into a newly formed protoplanetary disk (seen face on with the protostar being the light purple blob in the middle) by a supernova shock wave.
A recent analysis of chondrites by Carnegie's Myriam Telus was concerned with iron-60, a short-lived radioactive isotope that decays into nickel-60. It is only created in significant amounts by nuclear reactions inside certain kinds of stars, including supernovae or what are called asymptotic giant branch (AGB) stars.
Because all the iron-60 from the Solar System's formation has long since decayed, Telus' research, published in Geochimica et Cosmochimica Acta, focused on its daughter product, nickel-60. The amount of nickel-60 found in meteorite samples--particularly in comparison to the amount of stable, "ordinary" iron-56--can indicate how much iron-60 was present when the larger parent body from which the meteorite broke off was formed. There are not many options for how an excess of iron-60--which later decayed into nickel-60--could have gotten into a primitive Solar System object in the first place--one of them being a supernova.
While her research did not find a "smoking gun," definitively proving that the radioactive isotopes were injected by a shock wave, Telus did show that the amount of Fe-60 present in the early Solar System is consistent with a supernova origin.
Taking this latest meteorite research into account, Boss revisited his earlier models of shock wave-triggered cloud collapse, extending his computational models beyond the initial collapse and into the intermediate stages of star formation, when the Sun was first being created, an important next step in tying together Solar System origin modeling and meteorite sample analysis.
"My findings indicate that a supernova shock wave is still the most-plausible origin story for explaining the short lived radioactive isotopes in our Solar System," Boss said.
Boss dedicated his paper to the late Sandra Keiser, a long-term collaborator, who provided computational and programming support at Carnegie's Department of Terrestrial Magnetism for more than two decades. Keiser died in March.
The Daily Galaxy via Carnegie Institution
Image credit: courtesy of Alan Boss; top of page, Original Mockups | <urn:uuid:f35dc50b-7267-405c-8884-bc96077733d3> | 3.984375 | 782 | News Article | Science & Tech. | 22.162807 | 95,530,823 |
During an expedition off the South American coast, an international team of ocean scientists discovered that the gases ethane and propane are widespread, and are being produced by microorganisms in deeply buried sediments.
Prof. Kai-Uwe Hinrichs (Research Center Ocean Margins, University of Bremen), co-author Prof. John Hayes (Woods Hole Oceanographic Institution), and colleagues report new findings on the production of energy-laden gases in a paper in this week's online edition of the renowned Proceedings of the National Academy of Sciences of the U.S.A. (PNAS). The findings suggest that microbes in the deeply buried, vast ecosystem below the seafloor carry out hitherto unrecognized processes, which are highly relevant to both our understanding of global element cycles and the metabolic abilities of Earth's microbial biosphere.
"In a way, the finding was coincidental," Hinrichs states. Onboard the research drilling vessel JOIDES Resolution, the geochemist, now at the University of Bremen but then at Woods Hole Oceanographic Institution (WHOI), analyzed the gases in sediments buried up to 400 meters in the Equatorial Pacific off Peru. "We were swamped with samples: in nearly a thousand samples of up to 40 million-year-old sediment, we analyzed the gas content." Despite work shifts of up to 14 hours, the shipboard scientists soon had a backlog of unanalyzed samples, which turned out to be lucky. "When we later looked at the samples, we noticed that concentrations of ethane and propane were suspiciously high," Hinrichs adds. Soon the scientists realized that these gases were not artifacts or contaminants, but that they must have slowly escaped from the sediment.
The researchers began to wonder how to account for the presence of these gases. Normally, ethane and propane are known as typical products of fossil fuel generation at elevated temperatures and pressure, without direct involvement of microbes. In the PNAS article, the team argues that microbes played a key role in the formation of these hydrocarbons.
"Sediments contain organic material (the fossil remnant of oceanic plants and animals)," Hinrichs explains. "This material, a key ingredient in the carbon cycle, is the major food used by the deep biosphere. During its decomposition by microbes, acetate--the ionic form of acetic acid--is formed. We think that bacteria use hydrogen to convert acetate into ethane. Addition of inorganic carbon and hydrogen provides a route to propane."
In support of their hypothesis for a biological origin of the gases, the researchers point to several clues: "First, the sampling locations are remote from reservoirs of oil and natural gas, so that this source can be eliminated," Hinrichs says. "Moreover, the abundance of stable isotopes of carbon are markedly different from those in gases formed at high temperature," adds co-author John Hayes, a geochemist at Woods Hole Oceanographic Institution (WHOI).
Co-author Wolfgang Bach, geochemist and professor at the Bremer Research Center points out, "We also were able to demonstrate that under the conditions prevailing at depth, these processes could yield just enough energy for growth of bacterial communities."
The paper leads to several new questions that will be addressed in future work. In a current PhD project in the Organic Geochemistry Group at the Research Center Ocean Margins, experiments are being conducted to locate the sedimentary sites where the gases are hidden. "Interlayer spaces of clay minerals are the best candidates right now," Hinrichs says. Other experiments are currently being designed to find out more about how the gases are being formed. He adds, "One important goal right now is to study these processes under controlled conditions in the lab to verify or refine the proposed mechanism." Hinrichs knows that it may not be easy to simulate processes from the deep biosphere, but the geochemist hopes to identify and replicate the conditions needed to stimulate the microbes to produce a lot of these energy carriers.
Nancy Light | EurekAlert!
Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center
NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
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Sand Dune Stabilization with Plants in China
Sand deserts and sandy lands in northern China are situated in the temperate region between 35-40°N and 75-125°E. The area to the west of Helan Mountain Ranges belongs to the desert zone with annual precipitation below 150mm and sandy deserts makes up about 80% of the total area of sand deserts and sandy lands in northern China. In this highly desiccated desert zone there exist Taklimakan Desert, Gurban Tonggut Desert, Kumtag Desert, the Deserts in Qaidam Basin, Badain Jaran Desert, Tengger Desert and Ulan Buh Desert. There are many sand mountains in the vast expense of deserts, some of them are more than 200m in height.
KeywordsWind Erosion Sandy Land Hexi Corridor Sandy Desert Tengger Desert
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Bioengineers and physicists at the University of California San Diego, in a paper published in the current issue of the Proceedings of the National Academy of Sciences, have begun to address these fundamental questions.
The UC San Diego scientists focused their research on dense colonies of the rod-shaped bacteria Escherichia coli. By analyzing the spatial organization of the bacteria in a microfluidic chemostat – a kind of mini-circuit board for liquids rather than electrons – they found that growth and expansion of a dense colony of cells leads to a dynamic change from relative disorder to a remarkable re-orientation and alignment of the rod-like cells.
That finding, described in their paper “Biomechanical Ordering of Dense Cell Populations,” allowed them to develop a model of collective cell dynamics, and to use this model to “elucidate the mechanism of cell ordering, and quantify the relationship between the dynamics of cell proliferation and the spatial structure of the population.”
One of the authors, Lev S. Tsimring, at UC San Diego’s Institute of Nonlinear Science, explained the bioengineers’ use of bacteria to study the biomechanical ordering of cells.
“When environmental conditions are harsh, bacteria like to stick together. The most typical form of bacterial organization in nature is a biofilm: a dense quasi-two-dimensional colony of bacteria. Biofilms grow in and on living tissues, the surfaces of rocks and soils, and in aquatic environments,” he said, “but they’re also found in man-made systems and devices such as industrial piping and artificial implants. And bacteria are known to actively migrate toward surfaces and small cavities, where they form high-density colonies.”
At low densities, he said, bacteria and other cells communicate “remotely” by sending chemical signals – “chemotaxis” – but, as they aggregate and form dense communities, direct biomechanical contacts play a bigger and bigger role in how they organize themselves.
“Although previous studies have explored the complex signaling mechanisms in the early stages of biofilm formation,” Tsimring said, “the biomechanics of direct cellular contacts have received little attention. We focused, therefore, on the structure and dynamics of a growing two-dimensional colony of non-motile bacteria.”
His fellow researcher, Jeff Hasty, at the Institute for Nonlinear Science and UC San Diego’s Department of Bioengineering, said the team’s work provides a multiscale description of cell colony growth.
“Our results reveal how cell growth and colony expansion trigger the formation of the orientational order in the population,” Hasty said, “which, in turn, affects the mechanical and biochemical properties of the colony.”
The details of their research, the authors say, helps scientists understand how the local interaction of elementary components leads to collective behavior and the formation of a highly organized system.
Tsimring and Hasty collaborated with Scott Cookson, of the Department of Bioengineering, and Dmitri Volfson, now at Rosetta Inpharmatics LLC.
Funding for the research was provided by the National Institutes of Health, the National Science Foundation, and UC MEXUS-CONACYT.
Paul K. Mueller | Newswise Science News
O2 stable hydrogenases for applications
23.07.2018 | Max-Planck-Institut für Chemische Energiekonversion
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
23.07.2018 | Science Education
23.07.2018 | Health and Medicine
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Unmanned Aircraft Systems (UAS) in action at the Kilauea Volcano
Scientists are using UAS mounted sensors to help support monitoring and data acquisition needs at the Kilauea Volcano in Hawaii.Learn More
10 Things You May Not Know About Our Coasts
Coasts provide many benefits to their inhabitants but are threatened by changing conditions. Scientists are working to understand the related impacts.Learn More
Mission Areas L2 Landing Page Tabs
Understanding a changing world and how it affects our natural resources, livelihoods, and communities. Science plays an essential role in helping communities and resource managers understand the local to global implications of change, anticipate the effects of change, prepare for change, and reduce the risks associated with decisionmaking in a changing environment.
Land Resource science is essential to improve understanding of past and present change; develop relevant forecasts; and identify those lands, resources, and communities most vulnerable to Earth system change processes.Our Science Strategy
Instrumental measurements of climate variables (e.g., precipitation, temperature, ocean circulation, etc.) are only available over the past century or less. In order to quantify the rate and magnitude of natural climate variability going back in time beyond the 20th century, scientists rely on paleoclimate reconstructions.
A sediment trap time series in the northern Gulf of Mexico is used to better assess the control of environmental variables (e.g., temperature and salinity) on the flux of both microfossils and molecular fossils to the sediments. The information gained from sediment trap studies is used to develop better proxy-based estimates of past oceanographic conditions from analyses of microfossils and ...
The William T. Pecora Award is presented annually to individuals or groups that have made outstanding contributions toward understanding the Earth by means of remote sensing. Nominations for the 2018 award must be received by June 15, 2018.
Climate Change in the Chesapeake Bay Watershed: Effects on Riverine Discharge, Ecosystems, and Water Quality
The 64,000-square mile watershed that drains to the Chesapeake Bay is highly populated and has diverse land use, including forested, agricultural, and urbanized areas. Increased precipitation in the eastern United States over the last 100 years has affected stream flow and thus the loading of pollutants delivered to the bay. Such pollutants as suspended sediment and dissolved phosphorus and...
The retreat of glaciers in Glacier National Park, Montana, has received widespread attention by the media, the public, and scientists because it is a clear and poignant indicator of change in the northern Rocky Mountains of the USA. In 2017 the...
The simulation reflects the predicted exponential rise in atmospheric CO2 concentrations, a 2xCO2 "global warming" scenario, by 2030 with a concurrent warming of 2-3 degrees centigrade (4-5 degrees Fahrenheit) by the year 2050. In addition it assumes that precipitation, primarily during the winter, will increase over the same time period five to 10 percent. The animation view of the Blackfoot-...
USGS scientists have been involved for a number of years in the development and use of Structural Equation Modeling (SEM). This methodology represents an approach to statistical modeling that focuses on the study of complex cause-effect hypotheses about the mechanisms operating in systems. SEM is increasingly used in ecological and environmental studies and this site seeks to provide...
Modeling Past Variation in Florida Manatee Survival, Breeding, and Movements Rates to Establish Baselines for Aquatic Ecosystem and Restoration Research
Long-term monitoring data in the Manatee Individual Photo-identification System (MIPS), developed and coordinated by WARC-Sirenia Project in collaboration with Florida’s Fish and Wildlife Research Institute and Mote Marine Laboratory, are the basis for modeling manatee demography rates.
The Challenge: Accelerations in sea-level rise and changing environmental stressors have important implications for the integrity of coastal wetlands and for efforts to restore and protect the ecosystem services they provide. Their persistence and adaptation to these stressors depends on the net effects of changes in physical processes and biotic responses. Future planning by decision makers...
High-severity crown fires in Southwestern dry-conifer forests — resulting from fire suppression, fuel buildups, and drought — are creating large treeless areas that are historically unprecedented in size. These recent stand-replacing fires have reset extensive portions of Southwest forest landscapes, fostering post-fire successional vegetation that can alter ecological recovery trajectories...
Tropical storms and hurricanes wreak havoc with coastal forests where damage can vary with wind speed and approach from isolated treefalls to wide-area blowdowns of whole forests.
Monitoring and Assessing Effects of the Picayune Strand Restoration Project (PSRP) on the Florida Manatee
Critical information predicting condition changes in manatee habitat resulting from the alteration of freshwater flows to estuaries is needed to develop the PSRP Detailed Design and PSRP Operations Plan components and complete consultation under the Endangered Species Act.
In this interactive matching game developed by USGS and AmericaView, you’ll compare satellite images that show land cover change at various locations around the world. The goal is to find all the matching pairs of images in the shortest amount of time.
The Coastal National Elevation Database (CoNED) Project Viewer is a portal to the topobathymetric models created with the expertise of the expertise of the U.S. Geological Survey Earth Resources Observation and Science (EROS) Center near Sioux Falls, SD.
The EarthNow! Landsat Image Viewer displays imagery in near real-time as Landsat 7 and Landsat 8 orbit the Earth. Along with the near real-time video stream, EarthNow! also replays acquisition recordings from a list of previous Landsat overpasses. When Landsat 7 or Landsat 8 are out of viewing range of a ground station, the most recent overpass is displayed.
Shoreline change rates in salt marsh units in Edwin B. Forsythe National Wildlife Refuge, New Jersey
This dataset displays shoreline change rates at the Edwin B. Forsythe National Wildlife Refuge (EBFNWR), which spans over Great Bay, Little Egg Harbor, and Barnegat Bay in New Jersey, USA
Area of the Named Glaciers of Glacier National Park (GNP) and Flathead National Forest (FNF) Derived from Aerial and Satellite Imagery, 1966, 1998, 2005, 2015
These data represent a time series of the 37 named glaciers of Glacier National Park, MT, USA and two named glaciers in the Flathead National Forest.
USGS scientists have been involved for a number of years in the development and use of Structural Equation Modeling (SEM). This methodology represents an approach to statistical modeling that focuses on the study of complex cause-effect hypotheses about the mechanisms operating in systems.
The EarthExplorer (EE) tool provides users the ability to query, search, and order satellite images, aerial photographs, and cartographic products. In addition to data from the Landsat missions, EE provides access to MODIS land data products from the NASA Terra and Aqua missions, and ASTER level-1B data products over the U.S. and and Territories from the NASA ASTER mission.
Spatial patterns of development drive water use
Water availability is becoming more uncertain as human populations grow, cities expand into rural regions and the climate changes. In this study, we examine the functional relationship between water use and the spatial patterns of developed land across the rapidly growing region of the southeastern United States. We quantified the spatial pattern...Sanchez, G.M.; Smith, J.W.; Terando, Adam J.; Sun, G.; Meentemeyer, R.K.
Potential impacts of projected climate change on vegetation-management strategies in Hawai‘i Volcanoes National Park
Climate change is expected to alter the seasonal and annual patterns of rainfall and temperature in the Hawaiian Islands. Land managers and other responsible agencies will need to know how plant-species habitats will change over the next century in order to manage these resources effectively. This issue is a major concern for resource managers at...Camp, Richard J.; Berkowitz, S. Paul; Brink, Kevin W.; Jacobi, James D.; Loh, Rhonda; Price, Jonathan; Fortini, Lucas B.
U.S. Department of the Interior Climate Science Centers and U.S. Geological Survey National Climate Change and Wildlife Science Center—Annual report for 2017
IntroductionThe year 2017 was a year of review and renewal for the Department of the Interior (DOI) Climate Science Centers (CSCs) and the U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center (NCCWSC). The Southeast, Northwest, Alaska, Southwest, and North Central CSCs’ 5-year summary review reports were released in...Varela Minder, Elda
Movers and stayers: Novel assemblages in changing environments
How species will respond to ongoing climate and other change is of increasing concern.Most attention is given to how species move or are moved, but many species stay.Understanding the dynamics of new species combinations is essential for successful conservation in a changing climate.Increased attention to species movement in response to...Hobbs, Richard L.; Valentine, Leonie E.; Standish, Rachel J.; Jackson, Stephen T.
Temperature variations in the southern Great Lakes during the last deglaciation: Comparison between pollen and GDGT proxies
Our understanding of deglacial climate history in the southern Great Lakes region of the United States is primarily based upon fossil pollen data, with few independent and multi-proxy climate reconstructions. Here we introduce a new, well-dated fossil pollen record from Stotzel-Leis, OH, and a new deglacial temperature record based on branched...Watson, Benjamin I.; Williams, John W.; Russell, James M.; Jackson, Stephen T.; Shane, Linda; Lowell, Thomas V.
Ad hoc instrumentation methods in ecological studies produce highly biased temperature measurements
In light of global climate change, ecological studies increasingly address effects of temperature on organisms and ecosystems. To measure air temperature at biologically relevant scales in the field, ecologists often use small, portable temperature sensors. Sensors must be shielded from solar radiation to provide accurate temperature measurements...Terando, Adam J.; Youngsteadt, Elsa; Meineke, Emily K.; Prado, Sara G.
Building translational ecology communities of practice: insights from the field
Translational ecology (TE) prioritizes the understanding of social systems and decision contexts in order to address complex natural resource management issues. Although many practitioners in applied fields employ translational tactics, the body of literature addressing such approaches is limited. We present several case studies illustrating the...Lawson, Dawn M.; Hall, Kimberly R.; Yung, Laurie; Enquist, Carolyn A. F.
Developing a translational ecology workforce
We define a translational ecologist as a professional ecologist with diverse disciplinary expertise and skill sets, as well as a suitable personal disposition, who engages across social, professional, and disciplinary boundaries to partner with decision makers to achieve practical environmental solutions. Becoming a translational ecologist...Schwartz, Mark W.; Hiers, J. Kevin; Davis, Frank W.; Garfin, Gregg; Jackson, Stephen T.; Terando, Adam J.; Woodhouse, Connie A.; Morelli, Toni; Williamson, Matthew A.; Brunson, Mark W.
Early-career experts essential for planetary sustainability
Early-career experts can play a fundamental role in achieving planetary sustainability by bridging generational divides and developing novel solutions to complex problems. We argue that intergenerational partnerships and interdisciplinary collaboration among early-career experts will enable emerging sustainability leaders to contribute fully to a...Lim, Michelle; Lynch, Abigail J.; Fernández-Llamazares, Alvaro; Balint, Lenke; Basher, Zeenatul; Chan, Ivis; Jaureguiberry, Pedro; Mohamed, A.A.A.; Mwampamba, Tuyeni H.; Palomo, Ignacio; Pliscoff, Patricio; Salimov, R.A.; Samakov, Aibek; Selomane, Odirilwe; Shrestha, Uttam B.; Sidorovich, Anna A.
Foundations of translational ecology
Ecologists who specialize in translational ecology (TE) seek to link ecological knowledge to decision making by integrating ecological science with the full complement of social dimensions that underlie today's complex environmental issues. TE is motivated by a search for outcomes that directly serve the needs of natural resource managers and...Enquist, Carolyn A. F.; Jackson, Stephen T.; Garfin, Gregg M.; Davis, Frank W.; Gerber, Leah R.; Littell, Jeremy; Tank, Jennifer L.; Terando, Adam; Wall, Tamara U.; Halpern, Benjamin S.; Morelli, Toni L.; Hiers, J. Kevin; McNie, Elizabeth; Stephenson, Nathan L.; Williamson, Matthew A.; Woodhouse, Connie A.; Yung, Laurie; Brunson, Mark W.; Hall, Kimberly R.; Hallett, Lauren M.; Lawson, Dawn M.; Moritz, Max A.; Nydick, Koren R.; Pairis, Amber; Ray, Andrea J.; Regan, Claudia M.; Safford, Hugh D.; Schwartz, Mark W.; Shaw, M. Rebecca
Toward an effective practice of translational ecology
No abstract available.Jackson, Stephen T.; Garfin, Gregg; Enquist, Carolyn A.F.
A three-dimensional mapping of the ocean based on environmental data
The existence, sources, distribution, circulation, and physicochemical nature of macroscale oceanic water bodies have long been a focus of oceanographic inquiry. Building on that work, this paper describes an objectively derived and globally comprehensive set of 37 distinct volumetric region units, called ecological marine units (EMUs). They are...Sayre, Roger; Wright, Dawn J.; Breyer, Sean P.; Butler, Kevin; Van Graafeiland, Keith; Costello, Mark J.; Harris, Peter T.; Goodin, Kathleen; Guinotte, John M.; Basher, Zeenatul; Kavanaugh, Maria T.; Halpin, Patrick N.; Monaco, Mark E.; Cressie, Noel; Aniello, Peter; Frye, Charles; Stephens, Drew
The Earth Resources Observation and Science Center offers educational resources designed for elementary- and middle-school students. The U.S. Geological Survey offers more options through its science education resource page.
Map of Alaska showing probability (%) of change occurrence. Insets show fire boundaries from the Bureau of Land Management (BLM) Large Fire Database and Landsat 8 imagery (bottom right; 2016) north of Fairbanks, Alaska.
What it takes each day to keep Landsat 7 operating smoothly. Hear the stories from inside the L7 Mission Operation Center.
Waterfowl populations in the northern Gulf of Mexico (NGOM) rely extensively on plants that grow under the surface in shallow waters, know as submerged aquatic vegetation (SAV), as a critical food resource in the winter season. SAV roots, shoots, and seeds provide high carbohydrate wildlife food that sustains valuable waterfowl species, including the American Wigeon,...
A unique effort to seasonally translocate fish, termed “fish rescue”, has quietly emerged in the Pacific Northwest as a way to reduce drought related mortality in wild fish by manually moving individuals from fragmented areas to either free-flowing habitat or artificial rearing facilities, providing refuge during periods of low flow. Work supported by the Northwest CASC...
Fog along the Yukon River showing a Black Spruce dominated forest in the foreground, which is prone to wildfire. Photo by Bruce Wylie, USGS
A group of second-graders from the Garretson School District in Garretson, South Dakota pose for a photo at the Earth Resources Observation and Science Center near Sioux Falls, SD.
The Moderate Resolution Imaging Spectroradiometer (MODIS) sensor is located onboard NASA’s Terra and Aqua satellites. The Visible Infrared Imaging Radiometer Suite (VIIRS) sensor is located onboard the joint NASA/NOAA Suomi National Polar-Orbiting Partnership (S-NPP) and data products created by NASA provide a continuation of the MODIS data heritage. These data are crucial...
Landsat 8 shows the effects after Volcan de Fuego erupted in Guatemala.
At the USGS EROS Center, we study land change, operate the Landsat satellites, and maintain the longest, continuously acquired collection of images of the Earth's land surface.
USGS EROS Center (https://eros.usgs.gov/)
Kass Green talks about the role Landsat plays to help create high resolution maps, the benefits of the archive at EROS and the value of Landsat imagery to agencies throughout the government.
The “LP DAAC Prospectus: 2017 to 2019” short video features the National Aeronautics and Space Administration’s (NASA) Land Processes Distributed Active Archive Center (LP DAAC), a key access point for global land remote sensing data. The video provides an overview of the significance of the LP DAAC’s archive and distribution functions, explains the depth of the user...
Engineers and scientists from both Landsat and Sentinel missions are working together to calibrate observation data and validate its quality to improve the science using these resources.
Jim Vogelmann discovered something interesting about Analysis Ready Data (ARD) these last few months as he and his colleagues worked on finding a better way to quantify fire risk in the Great Basin of the western United States.
ARD, Vogelmann learned, works really well.
Kyle Douglas-Mankin wants to know where the raindrops go when they fall on the arid and semi-arid landscapes of the Upper Rio Grande Basin.
Life in satellite flight operations is busy enough without the disruption of uprooting and moving an entire Mission Operations Center (MOC). Yet that’s been the reality for the Landsat 7 MOC as it transitioned this spring into a new address at the Goddard Space Flight Center in Greenbelt, MD.
The advent of remote sensing was a boon to the ancient science of phenology.
Satellite data offered a global view of nature’s seasonal life cycles that historical tabulators of budding trees and buzzing bees could scarcely imagine.
From the start, however, remotely sensed phenology has come with caveats.
It sounds like a kind of science-fiction fantasy—space trains chugging along on orbital tracks 705 kilometers above the Earth.
In fact, they are real—in a manner of speaking.
It began with a tree falling onto a power line.
There were sparks, then very quickly a wilderness ablaze. In its first 13 hours, the Las Conchas Fire that erupted just west of Bandelier National Monument in New Mexico on June 26, 2011, spread at an acre per second. By the time the last embers died weeks later, it had grown into what then was the largest wildfire in New Mexico history....
New research has revealed significant changes to Alaska’s landscape in recent decades
EROS team earns top honor from Department of Interior for work with international body.
Remotely-sensed data key to response in tracking danger in areas like Montecito
Former Chief Scientist's contributions as head of Landsat Science Team, commitment to education recognized
Scientists at EROS use remote sensing data to assist in the understanding of water dynamics in Upper Klamath | <urn:uuid:6e706154-9bb9-4d91-ab5f-1965ef9e7645> | 3.4375 | 4,098 | Content Listing | Science & Tech. | 34.994769 | 95,530,896 |
Cygnus X-1 belongs to a high-mass X-ray binary system about 6000 light years from the Sun that includes a blue supergiant variable star designated HDE 226868 which it orbits at about 0.2 AU, or 20% of the distance from the Earth to the Sun. A stellar wind from the star provides material for an accretion disk around the X-ray source. Matter in the inner disk is heated to millions of kelvin (K), generating the observed X-rays.
Friday, January 23, 2009
Cygnus X-1 is a well known galactic X-ray source in the constellation Cygnus. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux of 2.3×10−23 Wm−2Hz-1. Cygnus X-1 was the first X-ray source widely accepted to be a black hole candidate and it remains among the most studied astronomical objects in its class. It is estimated to have a mass about 8.7 times the mass of the Sun and has been shown to be too compact to be any known kind of normal star or other likely object besides a black hole. If so, the radius of its event horizon is probably about 26 km. | <urn:uuid:0a11304b-6055-40b1-b802-f6c3cf078d1d> | 3.703125 | 272 | Personal Blog | Science & Tech. | 76.118628 | 95,530,905 |
DNA, it has turned out, isn't all it was cracked up to be. In recent years we learned that the molecule of life, the discovery of the 20th century, did not -- could not -- by itself explain the huge differences in complexity between a human and a worm.
Forced to look elsewhere, scientists turned to RNA, a direct yet more complex transcript of DNA. But methodological problems have historically plagued the study of RNA regulation in living cells, limiting not only the accuracy of results but also our understanding of RNA's role in human disease.
But now, in research to appear in the November 2 advance online issue of Nature, Robert B. Darnell, head of the Laboratory of Molecular Neuro-oncology at Rockefeller University and a Howard Hughes Medical Institute investigator, and his team have changed all that.
By adapting techniques mastered in the test tube and combining them with high throughput technology, the team has developed a genome-wide platform to study how specialized proteins regulate RNA in living, intact cells. The platform allows researchers to identify, in a single experiment, every sequence within every strand of RNA to which proteins bind. The result is an unbiased and unprecedented look at how differences in RNA can explain how a worm and a human can each have 25,000 genes yet be so different.
"RNA offers a way to make the cell much more complex than what this limited set of genes can offer," says Darnell, who is Robert and Harriet Heilbrunn Professor at Rockefeller. "But how is RNA being regulated in different conditions and diseases, and in different cell types? With this platform, we now have a way to address all these questions."
Traditional methods used molecules to extract protein-RNA complexes from living tissue. But often the molecule only extracted the RNA. Other times, the protein bound too weakly to survive the purification process, which involved stripping the complex of unwanted debris. To address the issue, Darnell and his team used a trick from test-tube biochemistry that molecularly cements these regulatory proteins to RNA at the moment they touch. The technique, when applied to high throughput sequencing, is called high throughput sequencing-cross linking immunoprecipitation, or HITS-CLIP for short.
Since the RNA and RNA-binding protein are fused together, the researchers can really beat up the extract and rigorously purify the protein without fear of losing the RNA. At the end of the day, they are left with the RNA sequence to which the protein was bound. They can then take these sequences to Rockefeller's high throughput sequence facility, and with the help of Research Support Specialist Scott Dewell, overlay them onto the genome and see where they match. What they get is a map of every position on every transcribed RNA where the RNA binding protein is binding.
When DNA is transcribed into RNA, the primary transcript is divided into many blocks called exons, which are separated by empty spaces. In order to convert the transcript into some sort of message, all the spaces need to be removed; but if an exon is dropped, a different version of that protein, which could carry a very different message, is created. "That's RNA splicing," says first author Donny Licatalosi, a postdoctoral associate in the lab. "It is what gives rise to this massive pool of diverse and complex tissues with a relatively small number of genes."
In the past, the group used a sophisticated process of evidence and inference to make predictions of the points of regulation along the transcript. "Now, we have direct biochemical validation that these interactions occur in the brain to regulate splicing," says Licatalosi.
And as it turns out, "The observed map -- and this was amazing -- looked just like our predicted map," says Darnell.
Darnell, Licatalosi and their colleagues Aldo Mele, a research assistant, John Fak, a research assistant, Sung-Wook Chi, a graduate fellow in computational biology and medicine, Xuning Wang, assistant director of biocomputing and Jennifer Darnell, a research associate professor, looked at an RNA-binding protein called Nova2 that is found exclusively in neurons. They found that depending on where Nova2 binds to RNA, they could predict and directly observe whether an exon would be included or excluded in the final transcript, and which protein version it created. "The cell seems to be going through great trouble to regulate these RNAs in different conditions and different cell types," says Darnell. "When RNA developed the ability to make a more stable copy of itself -- DNA -- it didn't write itself off as a relic for the textbooks. It stayed at the core of complex processes in the cell."
This research was supported in part by the National Institutes of Health.
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Living mammals are placed into one of three major groups, depending on the way the animal completes its embryonic developement. One small group of mammals are the monotremes, which are egg-laying mammals. The monotremes include only three species, the duckbill platypus and two kinds of echidnas or spiny ant-eaters. All three are found only in Australia and New Zealand. These bizarre creatures differ from all other mammals because the female lays eggs, but when the young hatch she feeds them with her milk; the mother has no breasts or nipples, instead the milk seeps from small openings in her abdomen and is lapped up by the young.
Other mammalian features of the monotremes are the presence of hair and warm-bloodedness. However, they also have a number of reptilian features; for intance, their skeletons have reptilian shoulder girdles, and like reptiles, they have only one external opening for eliminating all body wastes as well as for reproduction. Most zoologists believe that monotremes separated early in evolution from the main mammalian line and do not belong to a group which was ancestral to the other mammals. | <urn:uuid:300cdf7c-13f4-4345-b584-671ac8dda317> | 3.5625 | 240 | Knowledge Article | Science & Tech. | 36.077289 | 95,530,956 |
In a joint publication in PLoS One, researchers from the University of Amsterdam and University of Viçosa (Brazil) show evidence of spectacular behavioural changes induced by a parasitic wasp in the caterpillar of a moth species.
After the wasp has oviposited eggs in the body of the caterpillar, these develop into larvae that live on the body fluids of the caterpillar. After the wasp larvae crawl out of the caterpillar to pupate, the caterpillar acts as a bodyguard to defend them from predator attacks.
A research team from the Institute for Biodiversity and Ecosystem Dynamics (IBED) of the University of Amsterdam worked together with the Entomology section of the Federal University of Viçosa (Brazil) to study such behavioural changes induced by parasites. In a recent publication in the new electronic journal PLoS One, the researchers offer evidence that behavioural changes of the host are beneficial to the parasite in the field. In Brazil, the team studied the caterpillars of a moth that feed on leaves of the native guava tree and an exotic eucalyptus.
These small caterpillars are attacked by insect parasitoid wasps, which then quickly insert up to 80 eggs into them. Inside the caterpillar host, a cruel drama takes place: the eggs of the parasitoid hatch and the larvae feed on the body fluids of the host. The caterpillar continues feeding, moving and growing like its unparasitised brothers and sisters. When the parasitoid larvae are full-grown, they emerge together through the host’s skin, and start pupating nearby. Unlike many other combinations of host and parasitoid, the host remains alive and displays spectacular changes in its behaviour: it stops feeding and remains close to the parasitoid pupae.
Moreover, it defends the parasitoid pupae against approaching predators with violent head-swings (see films via link below). The caterpillar dies soon after the adult parasitoids emerge from their pupae, so there can be no benefit whatsoever for it. In contrast, unparasitised caterpillars do not show any of these behavioural changes.
The research team found that parasitoid pupae that were guarded by caterpillars in the field suffered half as much predation as those without a bodyguard. Hence, the behavioural changes of the host result in increased survival of the parasitoids due to the host acting as a bodyguard of the parasitoid pupae. Whereas it is still unclear how the parasitoid changes the behaviour of its host, it is tempting to speculate. The research team found that one or two parasitoid larvae remained behind in the host. Perhaps these larvae affect the behaviour of the caterpillar, and sacrifice themselves for the good of their brothers and sisters.
Cause or effect?
There are many examples of parasites that induce spectacular changes in the behaviour of their host. Flukes, for example, are thought to induce ants, their intermediate host, to move up onto blades of grass during the night and early morning. There they firmly attach themselves to the substrate with their mandibles, and are thus consumed by grazing sheep, the fluke’s final host. In contrast, uninfected ants return to their nests during the night and the cooler parts of the day. Another example of behavioural change is that of terrestrial insects, parasitised by hairworms, which commit suicide by jumping into water allowing the adult hairworms to reproduce. Behavioural changes like these are thought to be induced by the parasite so as to increase its transmission to the final host, but there are alternative explanations. It is possible, for example, that the hosts already behaved differently before becoming infected. Hence, infection is a consequence of different behaviour, not its cause. Increased transmission can also be called into question: the behavioural changes of the host may result in increased attacks by other non-host animals, and this would seriously decrease the probability of transmission. Increased transmission should therefore always be tested under natural conditions. The research of the Dutch and Brazilian researchers is the most complete and convincing case for induction of behavioural changes, clearly showing that it is the parasite that profits from it.
This research was supported by the Tropical Research division of the Netherlands Organisation for Scientific Research (NWO-WOTRO).Publication information:
The online article can be viewed via: http://www.plosone.org/doi/pone.0002276. This website also includes accompanying images.
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This comes from a report commissioned by Rafael Martínez Fortún, from the town of Molina de Segura in Murcia, whose farm was struck by the largest meteorite recovered to date in Spain. In 1863, Queen Isabel II accepted it as a donation to the National Museum of Natural Sciences, where it has been conserved and exhibited ever since.
The Martínez Fortún account forms part of a recent study published in the magazine Astronomy and Geophysics by scientists Jesús Martínez Frías, planetary geologist at the Centre for Astrobiology (INTA/CSIC), and Rosario Lunar, chair in Crystallography and Mineralogy at the Complutense University of Madrid. Martínez Frías tells SINC the Molina de Segura meteorite “weighed around 144 kilos at the time it fell, but it was divided into various parts, and the largest, weighing 112.5 kilos, is the one currently on display at the National Museum of Natural Sciences (MNCN) in Madrid”.
The authors say this was an ordinary chondrite, “a very primitive rocky meteorite made out of small spherical particles, known as chondrules, which resulted from the solidification of dust and gas in the primigenious solar nebula, which gave birth to the Solar System and our own planet”. Chondrites, which make up more than 85% of all known meteorites, are divided into various types depending on their mineralogy, texture and geochemistry. The Molina de Segura one is a type H5 meteorite because of its high iron content and because it belongs to petrological type “5” (a number indicating the degree of alteration experienced in the “parent asteroid”).
Aside from the mineralogical and geochemical features of the Molina de Segura meteorite, the study also includes much of the report commissioned by Rafael Martínez Fortún. The owner of the barley plot where the extraterrestrial rock fell commissioned and legally registered the “literal testimony of the information ad infinitum in order to a confirm the physical phenomena observed when an aerolite fell to Earth in the early hours of December 24, 1858”. This document and others, seen by SINC, detailing the circumstances around the event, have seen the light of day thanks to the work of experts in the MNCN archive.
They thought it would hit the spire of the cathedral
One of the witnesses relates that “at a quarter past two in the morning” the atmosphere was suddenly illuminated by “a huge star of a brightness that eclipsed the moon, and that moved from overhead towards the north”. Another witness said he saw “a globe of the most brilliant fire and beautiful colours, which seemed as though one of the stars was falling to Earth from the sky”. “It passed over this city so low over the tower of the cathedral that they thought it would brush its lantern, but that didn’t happen. Instead it carried on for another three leagues, saving the city and its surrounding districts”, continues the report commissioned by Martínez Fortún, in whose farm the meteorite landed.
The meteorite’s impact caused such a tremor that it awoke the residents of Molina de Segura, a town in the lowlands of Murcia that is today home to around 65,000 inhabitants. “Many people who had been asleep were awoken and all of them, except those who had seen the phenomenon outside, believed it was one of the storms that are so common in the area, and were filled with fear,” continues the report. Many of those making statements said they had heard a loud noise “like canon fire”, accompanied by a shuddering of the earth “like that caused by an earthquake”.
Some people who were curious went to the site of the impact a few days later “and they were all confused, without knowing what could have caused it”. After moving the soil a little, and finding nothing, they “completely forgot” the event. Later, “during the barley harvest”, one of the workers noticed a hole caused by the meteorite “and upon digging around with his sickle hit something hard, and he told his fellow workers”, whose curiosity led them the dig deeper into the earth to see what they could find.
“They found a four-sided stone of a blackish colour and a weight that was extraordinary in comparison to its volume, because it weighed ten arrobas (old Spanish unit of weight = 25.36 pounds) and 15 pounds. This, together with the fact that it did not look anything like any stone any of them had ever seen before in that area or anywhere else, impressed them greatly, and one of them chipped off a piece by striking it with an iron hammer”, the report relates.
The place where the meteorite fell to earth, “located in the Partido de la Ornera”, is today known as the “Surroundings of the Rellano de Molina de Segura”, and has been declared a “site of geological interest” in the Murcia region. The local city council has suggested carrying out a detailed study of the impact zone, with the help of the scientists, to see whether any new information or fragments come to light.
Queen agrees to accept donation of the meteorite
When Rafael Martínez Fortún found out that an “aerolite” had fallen on his land, he decided to “send it to one of the scientific museums of the Kingdom so that it can be made available to men of science, who can study it with due attention”. With this in mind, he gathered the testimony of the witnesses and included these along with other information in a report that he registered before a judge in Murcia.
Queen Isabel II accepted the donation of the meteorite for the collection of the National Museum of Natural Sciences, at that time directed by Mariano de la Paz Graells, according to the documentation from the museum’s own archives. Scientists at the time studied the meteorite and extracted some fragments in order to analyse them.
As the years went by, some more small pieces of the Molina de Segura meteorite were sent to various collections and institutions around the world, such as the Natural History Museum in the United Kingdom, the Field Museum in Chicago, United States, and the Vatican’s meteorite collection.
The scientific publication by Martínez Frías and Rosario Lunar includes this information, and the authors have also proposed that the International Meteoritical Bulletin, considered the official data base of all the world’s meteorites, change its name from “Molina meteorite”, under which it has been registered, to “Molina de Segura meteorite”. They feel this is more precise, since meteorites bear the name of the place where they fall or are found (or if this is not possible, the nearest place), and Molina’s name was changed to Molina de Segura in 1916, following a proposal by the Royal Geographic Society.
The Murcian city where the largest meteorite found in Spain fell to Earth recently organised a scientific conference to commemorate the 150th anniversary of the event, which included a seminar-workshop given by María Paz Martín, a technical expert at the National Institute of Aerospace Technology (INTA), and a talk on meteorites given by Martínez Frías. The researcher stresses the importance of these types of rock “because they are unique materials that allow us to understand more about the primigenous material of the Solar System, and also to explore other planetary bodies (such as Mars or the Moon, thanks to the meteorites that originate from them) and to evaluate the consequences of large impacts during the geo-biological evolution of the Earth”.
In 1858, the same year as the Molina de Segura meteorite fell, the German chemist Friedrich Wöhler discovered that some meteorites transport organic material and suggested, for the first time, that these extraterrestrial rocks could be carriers of life.
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- Open Access
Numerical studies of geomagnetically induced electric field on seafloor and near coastal zones incorporated with heterogeneous conductivity distributions
© Goto. 2015
Received: 15 January 2015
Accepted: 10 November 2015
Published: 2 December 2015
Abrupt changes of geomagnetic field can make large induced electric field and resultant electric current on the earth, which is called as geomagnetically induced current (GIC). It can yield damages to pipelines, cables, and other architectures. For understanding the phenomena and future risks of GIC, it is necessary to evaluate how the sub-surface electrical conductivity structure is important for the GIC because the heterogeneous conductivity structure in the crust and mantle affects the induced electrical current locally. The hazard prediction based on the homogeneous earth may result in the underestimation. Here, I introduce possible cases of geomagnetically induced electric field (GIE) on seafloor and near coastal areas, based on numerical forward simulations on one-, two-, and three-dimensional (1-D, 2-D, and 3-D) earth’s structure including the sea layer. On the 1-D case, I show the possible amplitude of GIE on the seafloor, far from the coastal area. The second case study comes from 2-D forward simulation, in which the straightly elongated coastal line is assumed, and various sub-surface and sub-seafloor conductivity structures are imposed. The numerical results suggest that the amplitude of GIE on land becomes more than two times larger than that of the homogeneous earth without the sea layer. The width of land zone with larger GIE is about 20 km from the coast. In forward modeling with a simplified 3-D bathymetry, land electric field near the bay area increases with about ten times larger than that of the inland one. The seafloor GIE near the peninsula area also indicates about four times larger value than that of the other area at the same water depth. These phenomena can be explained by the boundary charge along the coastal area. I conclude that 3-D earth’s conductivity structure including the realistic bathymetry and sub-surface and sub-seafloor structures should be essential and focused for the hazard assessment of GIC.
Geomagnetic storms are potentially hazardous to human society. The electric field in the earth, induced by the geomagnetic storms, generates the large unpredictable electric current in conductors on the earth’s surface. This is so-called geomagnetically induced current (GIC), which can yield damages to pipelines, railways, cables, and other architectures which have long electrical conductor systems. For example, the end-to-end voltages associated with GIC can be very large along power lines and trans-oceanic submarine communication cables. Buried pipelines may suffer from serious corrosion of the steel due to GIC.
One of the famous damages is emerged on the Hydro-Québec power system during the great magnetic storm on March 13, 1989. Bolduc (2002) reported that the electrical power supply was interrupted for many hours, and voltage instability which resulted in safety features tripping the transmission system costs 6.5 M$ in material damages alone. In his report, the system collapse followed a sudden large variation of geomagnetic field (e.g., about 1000 nT decrease in the north component within several minutes). The large GIC made the system unstable since a number of static compensators, essential for maintaining dynamic stability, started tripping one after the other. Another example of GIC is recorded in the southern Finland (Pirjola 2005; Pirjola 2012). The maximum current through a transformer neutral in the power grid was about 200 A at the geomagnetic variation (about 2000 nT within several minutes).
For understanding the phenomena and future risks of GIC, many efforts have been done. Although the number of directly observed data of GIC at the power grid (e.g., Watari 2015) is limited, the recent numerical studies try to cover the lack of observation and to attempt to assess the GIC. Thomson et al. (2009) introduced progress toward integrated European scale models of geomagnetic and geoelectric fields for modeling GIC in power grids and pipelines. Pulkkinen et al. (2010) presented a model for computing GIC from local geomagnetic field observations carried out in Hokkaido, Japan. The model composed of a layered sub-surface structure reproduced the observed GIC with a very good accuracy. Wei et al. (2013) interpolated sparsely distributed magnetometer data and predicted the surface electric field across North America at the geomagnetic storms in 1989 and 2003. Their estimation based on the layered regional earth models indicates good agreement between the measured and interpolated data. They also found that the induced electric field strongly depends on the local surface impedance, resulting in surprisingly strong electric field amplitudes along the Atlantic and Gulf Coast. Boteler (2014) focused the 1989 magnetic disturbance at Québec, estimated the electric field based on the layered earth model, and showed how uncertainty in the earth model influences the calculation. Püthe et al. (2014) calculated electric field on a layered earth model incorporated with 3-D surface conductance distributions, which was compared with observed ones.
The many model studies have been done; however, most of them are based on the layered earth model (without horizontal heterogeneity) and have not handled the spatial heterogeneity of earth’s conductivity structure. It is necessary to discuss how large impacts the heterogeneity has on the GIC estimation because the heterogeneous conductivity structure in the crust and mantle affects the induced electrical current locally. Lack of the view may result in underestimation of the GIC hazard. Since the highly populated cities are concentrated along the coasts, the conductivity contrast between land and ocean should be discussed quantitatively for the GIC predictions. Moreover, a few studies have been reported about the GIC on the seafloor and near the coastal areas. Similar to land, the long electrical conductor systems such as submarine cables and pipelines are installed on the seafloor and coastal area.
In this study, I introduce possible cases of geomagnetically induced electric field (GIE), on seafloor and near coastal areas, which yields the GIC, based on numerical forward simulations on one-, two-, and three-dimensional (1-D, 2-D, and 3-D) earth’s structure including the sea layer. Through the 1-D calculations, I will discuss how large GIE is expected on the seafloor. Although the similar evaluations on the seafloor with 1-D earth models has been published (Pirjola et al. 2000; Pirjola 2002; Boteler and Pirjola 2003), the more realistic sub-seafloor structure is adopted in this study. Then, the 2-D and 3-D calculations help us to understand the coastal effect on GIE, which will enhance the electric field near the ocean. Note that this paper is focused on the discussion of horizontal geoelectric field at the Earth’s surface. For computation of GIC in the power grid, etc., produced by the geoelectric field, other engineering investigations such as in Pirjola (2012) are required.
I employed theoretical and numerical methods for electric field calculations on 1-D, 2-D, and 3-D earth’s conductivity structures. In this study, the spatially homogeneous electric current in the magnetosphere or ionosphere is assumed to be a source of GIE. The primary magnetic field (directly generated from the source current) is common on the surface and has the horizontal components only. It is an assumption for the magnetotelluric sounding (e.g., Kaufman and Keller 1981) but will be not appropriate because of the heterogeneous pattern of source electric current of GIE as shown in Thomson et al. (2009; see Fig. 3 in their article). For example, as reviewed in Mareschal (1986), the induced electric field directly observed under the electrojet tends to be underestimated at long periods while the reverse (overestimation of the induced electric field) is true past the edges of the electrojet. Although the source heterogeneity should be dealt in the future work, the simple assumption can be applied at the mid latitude area far from the electrojet and also can be worth as a practical method to evaluate the averaged GIE at the high-latitude area.
Two contrastive models of sub-seafloor 1-D conductivity structures. The seawater conductivity is assumed as 4 S/m
Pacific plate (PAC) model
Philippine Sea plate (PHS) model
Depth 0–10 km bsf.
Depth 0–10 km bsf.
Upper most mantle
Depth 10–150 km bsf.
Depth 10-40km bsf.
Depth >150 km bsf.
Depth >40 km bsf.
Note that the GIE in this study is estimated in the frequency domain, not in the time domain. Although most of the GIC studies are based on the analysis of time series data, the GIE due to magnetic fluctuations can be written in the frequency domain such as in Eq. 5. Therefore, for the fundamental studies of GIE, it is described as a function of frequency in this study. The transform of the frequency-domain GIE to the time domain is easily achieved; the frequency-domain GIE per unit amplitude of magnetic fluctuation (as shown in Fig. 1), and the spectrum of observed magnetic field can give us the predicted spectrum of GIE. Inverse Fourier transform of the GIE spectrum will yield the time series of predicted GIE. In the following 2-D and 3-D calculations, the frequency-domain approach is also adopted.
The 2-D model can include both land and ocean with a straight coastline and is useful for demonstrating the coastal effect on GIE. The numerical calculation is based on the finite element method (FEM) developed by Uchida and Ogawa (1993), which follows the method described in Rodi (1976). The 2-D model has an elongated structure in which the conductivity can vary across the strike and to the depth. It consists of aggregation of small rectangular blocks having the own conductivity values. The induced electric field on land and seafloor are obtained by the calculation, assuming the unit amplitude of magnetic field on the sea/land surface.
As well known, the two modes of electromagnetic inductions are available for 2-D cases: the transverse magnetic (TM) mode and the transverse electric (TE) mode (e.g., page 37 in Chave and Jones 2012). In the TM mode, the magnetic field points in the strike of 2-D structure and the electric field lies in the plane orthogonal to strike. The TE mode has the complementary set, with electric field in the strike direction and the magnetic field orthogonal to the strike. In this study, I focus the TM mode induction for evaluation of the coastal effect on GIE. As typically shown in Vozoff (1972), the apparent resistivity at a frequency rapidly changes at a vertical contact of conductivity heterogeneity, similar to coastline. Since the amplitude of magnetic field is common at the earth’s surface in the TM mode theoretically, the rapid change means less-continuous electrical field across the vertical contact. On the contrary, in the TE mode, the apparent resistivity gradually changes across the vertical contact. It means that the TE-mode electrical field can be approximately inferred by interpolation of calculated results on the 1-D models. Therefore, the GIE estimation in the TM mode is more meaningful for the 2-D studies.
Results and discussion
As a result of the 1-D modeling studies (Fig. 1), the seafloor electric field cannot be negligible at shallow water and low frequency cases. In the case of water depth of 1000 m, the amplitude of electric field is relatively smaller than that of the land case (no seawater) but is still 15–30 % of the land case at the frequency of 0.001 Hz. It will be larger level if the water depth is less than 1000 m. On the contrary, in the deeper water case (e.g., 4000 m), the amplitude of electric field goes down less than 8 % of the land value. Such a small electric field is similar to the previous studies (Pirjola et al. 2000; Boteler and Pirjola 2003).
The quantitative estimation of seafloor electric field helps the discussion on how large voltages can be excited along the seafloor infrastructures. For example, an extreme magnetic storm in 1859, called as the Carrington event, brought the large geomagnetic change of about 1600 nT at Bombay, India (Tsurutani et al. 2003). They reported the continuous decrease of magnetic field during several thousand seconds. If surface geomagnetic fluctuations have the amplitude of 1600 nT and the frequency of 0.001 Hz, and a submarine cable or pipeline with length of 2000 km is installed on the seafloor with water depth of 1000 m, we can predict the end-to-end voltages along the infrastructure. By multiplying the electric field at 0.001 Hz in Fig. 1 (0.16–0.19 mV/km/nT), amplitude of magnetic field and the cable length, the voltages can be predicted as about 500–600 V. It is obvious that the shallower water environment increases the possibility of hazard on seafloor infrastructures. On the other hand, the seafloor GIE would be less hazardous at a higher frequency than 0.01 Hz in the case of water depth of 4000 m (Fig. 1), although the land case indicates the gradual increase at higher frequency. It is due to the shield effect by conductive seawater. In the case of water depth of 1000 m, the shield effect becomes weak and the cut-off frequency is shifted to about 0.1 Hz.
The 2-D modeling indicates the amplification of induced electric field is obvious in the coastal zone. Figure 2 indicates the results from four different models. The homogeneous underground model (Fig. 2a) and the land-side conductive model (Fig. 2b) commonly indicate the large induced electric field in the TM mode. For example, at a frequency of about 0.01 Hz on model A (Fig. 2), the averaged GIE at the area between the coast line to the 20 km inland is about 4.7 mV/km/nT, more than twice of inland GIE (about 2.1 mV/km/nT). In the other models and other frequencies, the amplification of GIE near the coast can be greater; e.g., about five times at 0.01–0.001 Hz on the model B (Fig. 2). Therefore, the horizontal heterogeneity should be considered for the GIE estimation.
The amplification along the coast is explained by the boundary charge at the coastline (e.g., Wannamaker et al. 1984); the TM mode electric field is normal to the vertical resistivity contacts in the earth. The continuity of electric current through the resistivity contacts can yield the discontinuity of electric field, and the resultant boundary charge will be induced at the resistivity contacts as sources for secondary electric field, which amplify the land electric field. Note that the large GIE zones spread offshore in Fig. 2a, b. It is due to the gradual change of bathymetry; the sea water layer becomes thick toward the offshore. The shallow water zones do not always contribute to the low frequency induction, so that the “coastline” at the low frequency is possibly shifted offshore.
The coastal effect yields not only amplification of electric field on land but also attenuation of seafloor electric field at some areas. In Fig. 2a, b, two zones with small GIE are revealed at a distance around +30 and +100 km, respectively. The former is located near the coastline, and the latter is found around the steep dipping of seafloor slope. It is also due to the boundary charge in the TM mode induction, which will be sources for secondary electric field attenuating the seafloor electric field.
The coastal effect of GIE is strongly affected by the shallow conductivity structure as shown in Fig. 2. The low conductive seafloor and high conductive seawater are directly attached each other in Fig. 2a, b. On the contrary, the crustal conductivity is varied gradually across the coastline in Fig. 2c, d. The latter models reduce the coastal effect in the TM mode (the amplification and attenuation of electric field which has been described above).
The deeper conductivity structure does not indicate the large coastal effect at the higher frequency but affects at the lower frequency. Based on the comparison between Fig. 2a and Fig. 2b, the GIE are almost common at the frequency higher than 0.001 Hz. However, differences are obvious at the lower frequency. If the electric field that drives GIC has large amplitude at such low frequencies, the mantle structure below the land should be considered.
The 3-D numerical modeling with a simple sub-surface structure (uniform conductivity of 0.01 S/m) demonstrates concentrations of electric current at the bay and peninsula areas. Figure 3 indicates the spatial distribution of electric field on and in the earth, together with the magnetic field at a frequency of 0.001 Hz. It is obvious that the electrical field is greatly amplified near the coastline (A in Fig. 3). This coastal effect is similar as in the 2-D modeling. The area A’ in Fig. 3 also indicates the large electric field near the coastline. It could be explained by the electric current avoiding the peninsula and seafloor high area (i.e., spur). The bay-like area has concentration of electric current, resulting in the larger electric field on land. Similarly, the different pattern of source magnetic field yields the large electric field on land near the coastline (B in Fig. 4). The amplitude is about ten times larger than that of the inland electric field, so that the coastal effects of GIE should be considered for the future hazard mitigations.
Not only the land but also the seafloor electric field is distorted by the complicated conductivity structure. In area C (Fig. 3), the offshore electric field is relatively higher (about four times) than that of the other offshore areas with the same water depth. This area is located along the coastline, where induced electric current avoiding the resistive peninsula will be concentrated. Similar offshore electric field with larger amplitude is observed at other areas such as D in Fig. 4. On this area, the geomagnetic field is also amplified largely as shown in area E (Fig. 4), which implies the current concentration in the ocean. Thus, the seafloor GIE could be increased near the shore area. The coastal ocean area is often characterized as the shallow water depth, so that the GIE could be similar amplitude to the land case (as discussed in the 1-D modeling case).
On the other hand, the small seafloor high has less effects of amplification of GIE. For example, the seafloor electric field on the spur-like structure (F in Fig. 3 and G in Fig. 4) indicates similar amplitude to the less complicated bathymetric area (F’ in Fig. 3 and G’ in Fig. 4). This is possibly due to the seawater upon the spur, which can play a role of “pass way” for electrical current avoiding the concentration around the resistive spur-like structure. It also might be due to the limited spatial width of spur; much wider seafloor high (and/or shallower top depth to the sea surface) could make a larger seafloor GIE as shown in the land case (e.g., A and A’ in Fig. 3)
For evaluation of GIE on seafloor and near coastal zones incorporated with heterogeneous conductivity distributions of the earth, I introduce possible cases of induced electric field based on theoretical and numerical forward simulations on 1-D, 2-D, and 3-D earth’s structure. On the 1-D case, the seafloor GIE is less hazardous at the higher frequency (Fig. 1; greater than about 0.01 and 0.1 Hz at water depth of 4000 and 1000 m, respectively). However, in the case of low frequency (e.g., 0.001 Hz) and the shallow water region (e.g., 1000 m), the GIE amplitude can reach 15–30 % of the land cases. The second case study comes from 2-D forward simulation, and suggests that the amplitude of GIE near the coastline becomes several times larger than that of the homogeneous earth without the sea layer. The land zone with amplification has a width of about 20 km from the coast. Finally, using the 3-D earth’s model including the complicated land-ocean distribution and bathymetry, we examined the coastal effect on GIE at the frequency of 0.001 Hz. The amplitude of land GIE near the bay area is about ten times larger than the inland value. In addition, the seafloor GIE near the peninsula area is about four times larger than that of the other area with same water depth. These phenomena can be explained by the boundary charge along the coastal area and the concentration of electric current near the coastline.
For assessment of GIC, I conclude that 3-D earth’s conductivity structure including the realistic bathymetry and the underground conductivity structure is essential and should be used. Although the simple model employing the 1-D earth’s structure will be valid in the middle of continental crust and the middle in ocean, both electric fields along and across the coastline are distorted by conductivity heterogeneity. As shown here, the coastal effects on GIE is complicated and strongly depends on the water depth of ocean, crustal conductivity structure (both land and ocean), and the shape of coastline. Fortunately, efforts of electromagnetic observations and data analysis provide us a global surface conductance (conductivity-thickness product) map, 3-D regional/local conductivity models (as in a review by Thomson et al. 2009, and the compiled global model by Alekseev et al. 2015). Recent advances of seafloor electromagnetic observations also show us 3-D conductivity structure below the seafloor (e.g., upper mantle structure below the Philippine Sea and the western margin of the Pacific Ocean presented by Tada et al. 2014). Note that the observed GIE is strongly distorted even at the very low frequency by small-scale and near-surface heterogeneities of conductivity distribution (e.g., Fujii et al. 2015). Since the distortion on the seafloor is smaller than one on the land (Püthe et al. 2014), heterogeneous geological structure near the land surface beneath the target (e.g., power lines) should be carefully included in the local/regional 3-D conductivity model, based on boreholes and geophysical explorations (seismic surveys, magnetotellurics, and so on). In addition, electric field at the seafloor due to a 2-D or 3-D ionospheric electric current, which is a source of GIE, was partly examined (Pirjola et al. 2000; Pirjola 2002). Numerical studies with 3-D conductivity structures with 3-D ionospheric current system will be achieved in near future and very helpful for assessing the GIC hazard.
The author is grateful to Dr. Shigeru Fujita, the Meteorological College, Japan, who gave me an opportunity and hints of this study. Discussion with Dr. Takafumi Kasaya, Japan Agency for Marine-Earth Science and Technology, about the 2-D coastal effects was quite fruitful for this study. Dr. Ikuko Fujii, the Meteorological College, Japan, and two anonymous reviewers greatly improved the manuscript. This study is partly supported by Grant-in-Aid for Scientific Research (No. 26289347) funded from the Ministry of Education, Culture, Sports, Science & Technology in Japan.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
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International researchers at the Large Hadron Collider (LHC), in Geneva, Switzerland, will soon embark on one of science’s greatest adventures. With its very high energy, previously seen only in cosmic rays, the particle collider will probe the inner structure of matter at distances ten times smaller than any previous experiments.
The LHC will address many of the mysteries surrounding the smallest particles of matter. It may also pierce secrets that the Universe has hidden since the early stages of the Big Bang, such as the nature of dark matter and the origin of matter itself. This will be the largest scientific experiment ever attempted and the complex international efforts to bring the 27 km-long machine to life, including Canada’s involvement, will also be explained.
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Temporal range: Lower Cambrian–Recent
Claus & Grobben, 1905
Chaetognatha, meaning bristle-jaws, and commonly known as arrow worms, is a phylum of predatory marine worms which are a major component of plankton worldwide. About 20% of the known species are benthic, and can attach to algae and rocks. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most chaetognaths are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from 2 to 120 millimetres (0.1 to 4.7 in).
Chaetognaths are transparent or translucent dart-shaped animals covered by a cuticle. The body is divided into a distinct head, trunk, and tail. There are between four and fourteen hooked, grasping spines on each side of their head, flanking a hollow vestibule containing the mouth. The spines are used in hunting, and covered with a flexible hood arising from the neck region when the animal is swimming. All chaetognaths are carnivorous, preying on other planktonic animals.
The trunk bears one or two pairs of lateral fins incorporating structures superficially similar to the fin rays of fish, with which they are not homologous, however: unlike those of vertebrates, these are composed of a thickened basement membrane extending from the epidermis. An additional caudal fin covers the post-anal tail. Two chaetognath species, Caecosagitta macrocephala and Eukrohnia fowleri, have bioluminescent organs on their fins.
Chaetognaths swim in short bursts using a dorso-ventral undulating body motion, where their tail fin assists with propulsion and the body fins with stabilization and steering. Some species are known to use the neurotoxin tetrodotoxin to subdue prey.
The body cavity is lined by peritoneum, and therefore represents a true coelom, and is divided into one compartment on each side of the trunk, and additional compartments inside the head and tail, all separated completely by septa. Although they have a mouth with one or two rows of tiny teeth, compound eyes, and a nervous system, they have no respiratory or circulatory systems.
The mouth opens into a muscular pharynx, which contains glands to lubricate the passage of food. From here, a straight intestine runs the length of the trunk to an anus just in front of the tail. The intestine is the primary site of digestion and includes a pair of diverticula near the anterior end. Materials are moved about the body cavity by cilia. Waste materials are simply excreted through the skin and anus.
The nervous system is reasonably simple, consisting of a ganglionated nerve ring surrounding the pharynx. The dorsal ganglion is the largest, but nerves extend from all the ganglia along the length of the body. Chaetognaths have two compound eyes, each consisting of a number of pigment-cup ocelli fused together. In addition, there are a number of sensory bristles arranged in rows along the side of the body, where they probably perform a function similar to that of the lateral line in fish. An additional, curved, band of sensory bristles lies over the head and neck.
The arrow worm rhabdomeres are derived from microtubules 20 nm long and 50 nm wide, which in turn form conical bodies that contain granules and thread structures. The cone body is derived from a cilium.
All species are hermaphroditic, carrying both eggs and sperm. Each animal possesses a pair of testes within the tail, and a pair of ovaries in the posterior region of the main body cavity. Immature sperm are released from the testes to mature inside the cavity of the tail, and then swim through a short duct to a seminal vesicle where they are packaged into a spermatophore.(Sexually and Asexually)
During mating, each individual places a spermatophore onto the neck of its partner after rupture of the seminal vesicle. The sperm rapidly escape from the spermatophore and swim along the midline of the animal until they reach a pair of small pores just in front of the tail. These pores connect to the oviducts, into which the developed eggs have already passed from the ovaries, and it is here that fertilisation takes place.
Chaetognaths are traditionally classed as deuterostomes by embryologists. Lynn Margulis and K. V. Schwartz place chaetognaths in the deuterostomes in their Five Kingdom classification. Molecular phylogenists, however, consider them to be protostomes. Thomas Cavalier-Smith places them in the protostomes in his Six Kingdom classification. The similarities between chaetognaths and nematodes mentioned above may support the protostome thesis—in fact, chaetognaths are sometimes regarded as a basal ecdysozoan or lophotrochozoan. Chaetognatha appears close to the base of the protostome tree in most studies of their molecular phylogeny. This may explain their deuterostome embryonic characters. If chaetognaths branched off from the protostomes before they evolved their distinctive protostome embryonic characters, they might have retained deuterostome characters inherited from early bilaterian ancestors. Thus chaetognaths may be a useful model for the ancestral bilaterian. Studies of arrow worms' nervous systems suggests they should be placed within the protostomes. According to a 2017 paper, chaetognaths are possibly related to gnathiferans.
Due to their soft bodies, chaetognaths fossilize poorly. Even so, several fossil chaetognath species have been described. Chaetognaths appear to have originated in the Cambrian Period. Complete body fossils have been formally described from the Lower Cambrian Maotianshan shales of Yunnan, China (Eognathacantha ercainella Chen & Huang and Protosagitta spinosa Hu) and the Middle Cambrian Burgess Shale of British Columbia (Oesia disjuncta Walcott), a view challenged by Conway Morris (2009). A more recent chaetognath, Paucijaculum samamithion Schram, has been described from the Mazon Creek biota from the Pennsylvanian of Illinois. Chaetognaths were thought possibly to be related to some of the animals grouped with the conodonts. The conodonts themselves, however, are thought to be related to the vertebrates. It is now thought that protoconodont elements (e.g., Protohertzina anabarica Missarzhevsky, 1973), are probably grasping spines of chaetognaths rather than teeth of conodonts. Previously chaetognaths in the Early Cambrian were only suspected from these protoconodont elements, but the more recent discoveries of body fossils have confirmed their presence then.
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- Systema Naturae 2000 Taxon: Phylum Chaetognatha per Cavalier-Smith Archived November 27, 2005, at the Wayback Machine. (select Cavalier-Smith in 'Classification by')—last retrieved November 25, 2006
- Matus, D. Q.; et al. (8 August 2006). "Broad taxon and gene sampling indicate that chaetognaths are protostomes". Current Biology. 16 (15): R575–R576. doi:10.1016/j.cub.2006.07.017. PMID 16890509.
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- Papillon, Daniel; Perez, Yvan; Caubit, Xavier; Le Parco, Yannick (2004). "Identification of Chaetognaths as Protostomes is Supported by the Analysis of Their Mitochondrial Genome". Molecular Biology and Evolution. 21 (11): 2122–9. doi:10.1093/molbev/msh229. PMID 15306659.
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- Hu, S.-X. (2005). "Taphonomy and palaeoecology of the Early Cambrian Chengjiang Biota from Eastern Yunnan, China". Berliner Paläobiologische Abhandlungen. 7: 1–197.
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- Szaniawski, H. (2002). "New evidence for the protoconodont origin of chaetognaths" (PDF). Acta Palaeontologica Polonica. 47 (3): 405–419.
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Recent Examples of elliptical galaxy from the Web
Taken together, these observations revealed a blazar – a giant elliptical galaxy with a spinning supermassive black hole at its core.
Taken together, these observations revealed a blazar - a giant elliptical galaxy with a spinning supermassive black hole at its core.
For example, astrophysicists believed that when two delicate disk galaxies like our Milky Way collide and merge, the process would wad them up into a single blobby elliptical galaxy.
Thirteen million light years away, a handful of relatively small galaxies revolve in a disk around the larger elliptical galaxy Centaurus A. There's nothing unusual about a collection of small galaxies orbiting a large one.
In 2009, a combination of optical and radio telescope observations produced this image of a spiral galaxy and an elliptical galaxy gradually becoming one, 13 million light years from Earth.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'elliptical galaxy.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
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Britannica.com: Encyclopedia article about elliptical galaxy
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We have examined the variation of carbon-14 content in annual tree rings, and investigated the transitions of the characteristics of the Schwabe/Hale (11-year/22-year) solar and cosmic-ray cycles during the last 1200 years, focusing mainly on the Maunder and Spoerer minima and the early Medieval Maximum Period. It has been revealed that the mean length of the Schwabe/Hale cycles changes associated with the centennial-scale variation of solar activity level. The mean length of Schwabe cycle had been ~14 years during the Maunder Minimum, while it was ~9 years during the early Medieval Maximum Period. We have also found that climate proxy record shows cyclic variations similar to stretching/shortening Schwabe/Hale solar cycles in time, suggesting that both Schwabe and Hale solar cycles are playing important role in climate change. In this paper, we review the nature of Schwabe and Hale cycles of solar activity and cosmic-ray flux during the Maunder Minimum and their possible influence on climate change. We suggest that the Hale cycle of cosmic rays are amplified during the grand solar minima and thus the influence of cosmic rays on climate change is prominently recognizable during such periods.
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With hurricane season in full swing, University of Maryland (UMD) A. James Clark School of Engineering and Department of Atmospheric and Oceanic Science (AOSC) experts accompanied national and local media to UMD’s Glenn L. Martin Wind Tunnel to explain why “it only takes one storm” to expose a region’s infrastructure vulnerabilities and emergency response challenges.
Joined by the TODAY Show’s Dylan Dreyer, as well as reporters from USA TODAY and metropolitan area broadcast outlets, UMD researchers set out to demonstrate how hurricane force winds – as well as flooding and storm surge – could spell trouble for coastal and riverine communities, and even the nation’s capital.
“Anywhere on the Gulf Coast to the upper East Coast, we’re all vulnerable,” said Dr. Antonio Busalacchi, Professor of Atmospheric and Oceanic Science and Director of UMD’s Earth System Science Interdisciplinary Center.
While early reports indicate this year’s North Atlantic hurricane season could carry fewer named storms than the historical average, both Busalacchi and Clark School engineers warn this is not the time to scale back on storm preparedness and resilience measures.
“It matters little what the number of named or major hurricanes expected for the 2015 season might be,” said Dr. Sandra Knight, Department of Civil and Environmental Engineering (CEE) Senior Research Engineer and Director of UMD’s Center for Disaster Resilience. “Some of the nation’s costliest storms – including Hurricane Sandy – were Category 2 or lower when they made U.S. landfall.”
With the help of Glenn L. Martin Wind Tunnel Director and Department of Aerospace Engineering Associate Professor Dr. Jewel Barlow and his researchers, Dreyer and others experienced up to 115 MPH wind speeds, demonstrating for viewing audiences just how powerful a Category 2 storm can be.
Wearing a harness strapped into bolts in the tunnel floor, one at a time, each of the reporters experienced how even sustained tropical storm force winds would make it very difficult for a person to stand, walk or even speak. As Barlow and his team slowly raised the wind speeds, each of the daring media personnel illustrated why a storm not classified as a “major hurricane” can still pack a serious punch – one that would cause significant damage and risks to human life.
In fact, a direct hit by a hurricane could spell calamity even for the Washington metropolitan area, Knight warned.
“Many people in the D.C. area do not realize that they’re actually in a tidal zone and that they are subject to coastal inundation,” she said. “Often, they feel like they are far away from the beach, so they are not at risk, but D.C. is certainly impacted by tides and coastal storms. The first step toward building resilience in the capital region is raising awareness to the fact that this is a coastal region, subject to many of the same risks shoreline communities face.”
Even with the recent completion of Washington’s 17th Street flood levee – designed to reduce risk to human safety and critical infrastructure from Potomac River flooding – floods pose a major concern throughout the area.
“The largest flood ever recorded in Washington, D.C. reached 7.9 feet in the early 1930s,” Knight said. “But, unprecedented storm surge could threaten billions of dollars’ worth of property, including critical infrastructure, national icons, and national security interests. When you factor in the impact of climate change and rising sea levels, you realize that a direct hit from even a Category 2 hurricane could carry a significant amount of risk in the nation’s capital.”
While the 17th Street levee serves to protect downtown Washington in the event a 100-year storm should hit the Potomac region, interior flooding – such as that resulting from heavy rainfall – is still a major risk. Even more, a significant weather event in the nation’s capital could have a spillover impact on other areas across the East Coast.
“Washington presents a unique scenario,” Knight said. “In addition to concerns over human safety and property, residents, emergency responders and policymakers must also consider how a major weather event in the capital region could impact government operations, national security, transportation systems, and the economy. For instance, a direct hit from a major hurricane could put military bases and Department of Defense facilities at risk. A major weather event in D.C. could also impact travel and the transport of goods, and force a government shutdown that could cause a ripple effect on the national economy.”
Such consequences only scratch the surface on why communities across the United States must build resilience, Knight said.
“Until the right measures and structural safeguards are in place, the odds a hurricane or summer storm could make a historical impact on the D.C. area – or another riverine or coastal community – will continue to rise,” she said.
View the TODAY Show’s, USA TODAY’s, WTOP’s, and ABC Washington’s coverage from the Glenn L. Martin Wind Tunnel.
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June 17, 2015 | <urn:uuid:a9e89f4b-fed2-46dd-a290-ab1517057d8c> | 2.71875 | 1,160 | News (Org.) | Science & Tech. | 39.124998 | 95,531,105 |
The dark reaction, also called the Calvin cycle as that is the actual mechanism of this reaction, is the second and final phase of photosynthesis. The final products of this stage are sugar molecules, which can be in the form of glucose or combined to create starch.
It is important to mention before getting too far into this discussion, that this process is called the dark reaction because it is light-independent. The name the “dark reaction” does not mean that this process happens at night. It actually happens at the same time as the light reaction. At night, the light reaction is unable to make the reactants required for this cycle so this process actually cannot occur during the night.
This reaction requires ATP and NADPH from the light reactions and CO2 from the atmosphere. The Calvin cycle occurs in the stroma of the chloroplast and is basically a series of reactions which result in the production of carbohydrates. The first reaction in this cycle is referred to as carbon fixation.
CO2 is needed to react with a starting material called RuBP, which is a 5 carbon molecule. This reaction is catalyzed by the enzyme Rubisco (RuBP Carboxylase/Oxygenase), which has a high affinity for carbon. It is important to note that Rubisco is actually capable of combining with both carbon and oxygen, but it is carbon that we want it to react with in this cycle.
This 6 carbon molecule is then almost instantaneously split into two three carbon molecules called 3-phosphoglycerate. The 6 carbon molecule created just before this is unstable and thus, splits. The products of the light reaction, NADPH and ATP are used to carry these two molecules through a series of reactions and produce two molecules of glyceraldehyde-3-phosphate (G3P). The energy from ATP and reducing power from NADPH drives this cycle.
Each turn of the cycle only adds a single carbon atom from CO2, meaning that this cycle needs to turn several times to produce glucose. Glucose can be formed when two molecules of 3-phosphoglycerate combine. However, these molecules also have to be recycled to keep the cycle moving.
Figure 1. This diagram provides a representation of the Calvin cycle. This diagram works with 6 carbon dioxide and 6 RuBP molecules so that it is able to illustrate one glucose molecule being formed. This diagram presents a rather simple diagram of this cycle (does not include the intermediate stages and molecules formed which have also not been discussed above). This image has been taken from http://www.studyblue.com/notes/note/n/life-102-final/deck/4788999.© BrainMass Inc. brainmass.com July 19, 2018, 3:32 pm ad1c9bdddf | <urn:uuid:bb436d02-362a-4c05-9fa3-2e07b14777e4> | 4.375 | 572 | Knowledge Article | Science & Tech. | 51.420446 | 95,531,122 |
Scientists a step closer to understanding 'natural antifreeze' molecules
Scientists have made an important step forward in their understanding of cryoprotectants – compounds that act as natural 'antifreeze' to protect drugs, food and tissues stored at sub-zero temperatures.
Researchers from the Universities of Leeds and Illinois, and Columbia University in New York, studied a particular type of cryoprotectants known as osmolytes. They found that small osmolyte molecules are better at protecting proteins than larger ones.
The findings, published in Proceedings of the National Academy of Sciences, could help scientists develop better storage techniques for a range of materials, including human reproductive tissue used in IVF.
Biological systems can usually only operate within a small range of temperatures. If they get too hot or too cold, the molecules within the system can become damaged (denatured), which affects their structure and stops them from functioning.
But certain species of fish, reptiles and amphibians can survive for months below freezing by entering into a kind of suspended animation. They are able to survive these extreme conditions thanks to osmolytes – small molecules within their blood that act like antifreeze –preventing damage to their vital organs.
These properties have made osmolytes attractive to scientists. They are used widely in the storage and testing of drugs and other pharmaceuticals; in food production; and to store human tissue like egg and sperm cells at very low temperatures (below ��ºC) for a long period of time.
"If you put something like human tissue straight in the freezer, ice crystals start to grow in the freezing water and solutes – solid particles dissolved in the water – get forced out into the remaining liquid.
This can result in unwanted high concentrations of solutes, such as salt, which can be very damaging to the tissue," said Dr Lorna Dougan from the University of Leeds, who led the study. "The addition of cryoprotectants, such as glycerol, lowers the freezing temperature of water and prevents crystallisation by producing a 'syrupy' semi-solid state. The challenge is to know which cryoprotectant molecule to use and how much of it is necessary.
"We want to get this right so that we recover as much of the biological material as possible after re-thawing. This has massive cost implications, particularly for the pharmaceutical industry because at present they lose a large proportion of their viable drug every time they freeze it."
Dr Dougan and her team tested a range of different osmolytes to find out which ones are most effective at protecting the 3D structure of a protein. They used an atomic force microscope to unravel a test protein in a range of different osmolyte environments to find out which ones were most protective. They discovered that smaller molecules, such as glycerol, are more effective than larger ones like sorbitol and sucrose.
Dr Dougan said: "We've been able to show that if you want to really stabilise a protein, it makes sense to use small protecting osmolytes. We hope to use this discovery and future research to develop a simple set of rules that will allow scientists and industry to use the best process parameters for their system and in doing so dramatically increase the amount of material they recover from the freeze-thaw cycle." | <urn:uuid:ed979014-d1ca-49b5-a505-9dbb22f79c7c> | 3.515625 | 695 | News Article | Science & Tech. | 25.709493 | 95,531,133 |
What is Epsilon Squared?
Epsilon Squared Formula
The formula is basically the same as that for omega squared, except that there is one less term in the denominator:
The first SS is the between sum of squares, df is the between degrees of freedom and MS is mean within sum of squares. The last SS is total sum of squares.
These values are obtained from ANOVA output, although epsilon squared itself will usually be calculated by hand. The result will differ very little from omega squared (Carroll and Nordholm, 1975) but will always be slightly larger (Okada, 2013).
Relationship to R2
The Dictionary of Statistics & Methodology (Vogt, 2005) defines epsilon squared as “another name for adjusted R2“. Frieman et. al state something similar: “Epsilon squared (ε2) is the adjusted R2 reported in many data analysis programs.” A glance at the two formulas for adjusted R2 and ε2 may cause you to think they are completely different, when in fact they are equivalent—at least, in SPSS. Adjusted r-squared is the term used for regression analysis calculations, while the equivalent formula is called epsilon-squared in ANOVA (Allen, 2017, p. 382).
In computer/hacker jargon, the term epsilon-squared means something else entirely. According to The Jargon File, it is an “insignificant amount”. For example, a single bolt compared to the cost of an entire space rocket is epsilon-squared.
Allen, R. (2017). Statistics and Experimental Design for Psychologists: A Model Comparison Approach. World Scientific Publishing Company.
Carroll and Nordholm, (1975). Sampling characteristics of Kelley’s ε2 and Hays w$2. Educational and Psychological Measurement. 35, 541-554.
Frieman et. al. (2017). Principles & Methods of Statistical Analysis.
Kelley, T. (1935) “An unbiased correlation ratio measure.” Proceedings of the National Academy of Sciences. 21(9). 554-559.
Mellinger, C. & Hanson, T. (2016). Quantitative Research Methods in Translation and Interpreting Studies. Taylor and Francis. Retrieved March 9, 2018 from: https://books.google.com/books?id=9TMlDwAAQBAJ
Okada, K. (2013). Is Omega Squared less biased? A comparison of three major effect size indices in one way ANOVA. Behaviormetrika. 40(2). 129-147.
Vogt, W.P. (2005). Dictionary of Statistics & Methodology: A Nontechnical Guide for the Social Sciences. SAGE.
If you prefer an online interactive environment to learn R and statistics, this free R Tutorial by Datacamp is a great way to get started. If you're are somewhat comfortable with R and are interested in going deeper into Statistics, try this Statistics with R track.Comments? Need to post a correction? Please post on our Facebook page. | <urn:uuid:e0e1b690-9053-4f35-a5b0-91a55f4651f7> | 3.53125 | 665 | Tutorial | Science & Tech. | 55.888679 | 95,531,148 |
Penetration depth is a measure of how deep light or any electromagnetic radiation can penetrate into a material. It is defined as the depth at which the intensity of the radiation inside the material falls to 1/e (about 37%) of its original value at (or more properly, just beneath) the surface.
When electromagnetic radiation is incident on the surface of a material, it may be (partly) reflected from that surface and there will be a field containing energy transmitted into the material. This electromagnetic field interacts with the atoms and electrons inside the material. Depending on the nature of the material, the electromagnetic field might travel very far into the material, or may die out very quickly. For a given material, penetration depth will generally be a function of wavelength.
According to Beer-Lambert law, the intensity of an electromagnetic wave inside a material falls off exponentially from the surface as
If denotes the penetration depth, we have
"Penetration depth" is one term that describes the decay of electromagnetic waves inside of a material. The above definition refers to the depth at which the intensity or power of the field decays to 1/e of its surface value. In many contexts one is concentrating on the field quantities themselves: the electric and magnetic fields in the case of electromagnetic waves. Since the power of a wave in a particular medium is proportional to the square of a field quantity, one may speak of a penetration depth at which the magnitude of the electric (or magnetic) field has decayed to 1/e of its surface value, and at which point the power of the wave has thereby decreased to or about 13% of its surface value:
Note that is identical to the skin depth, the latter term usually applying to metals in reference to the decay of electrical currents (which follow the decay in the electric or magnetic field due to a plane wave incident on a bulk conductor). The attenuation constant is also identical to the (negative) real part of the propagation constant, which may also be referred to as using a notation inconsistent with the above use. When referencing a source one must always be careful to note whether a number such as or refers to the decay of the field itself, or of the intensity (power) associated with that field. It can also be ambiguous as to whether a positive number describes attenuation (reduction of the field) or gain; this is usually obvious from the context.
The attenuation constant for an electromagnetic wave at normal incidence on a material is also proportional to the imaginary part of the material's refractive index n. Using the above definition of (based on intensity) the following relationship holds:
where denotes the complex index of refraction, is the radian frequency of the radiation, c is the speed of light in vacuum and is the wavelength. Note that is very much a function of frequency, as is its imaginary part which is often not mentioned (it is essentially zero for transparent dielectrics). The complex refractive index of metals is also infrequently mentioned but has the same significance, leading to a penetration depth (or skin depth ) accurately given by a formula which is valid up to microwave frequencies.
Relationships between these and other ways of specifying the decay of an electromagnetic field are further detailed in the article: Mathematical descriptions of opacity.
It should also be noted that we are only specifying the decay of the field which may be due to absorption of the electromagnetic energy in a lossy medium or may simply describe the penetration of the field in a medium where no loss occurs (or a combination of the two). For instance, a hypothetical substance may have a complex index of refraction . A wave will enter that medium without significant reflection and will be totally absorbed in the medium with a penetration depth (in field strength) of, where is the vacuum wavelength. A different hypothetical material with a complex index of refraction will also have a penetration depth of 16 wavelengths, however in this case the wave will be perfectly reflected from the material! No actual absorption of the radiation takes place, however the electric and magnetic fields extend well into the substance. In either case the penetration depth is found directly from the imaginary part of the material's refractive index as is detailed above. | <urn:uuid:183774c5-6bdc-47ba-801d-d1febfd31d18> | 3.578125 | 850 | Knowledge Article | Science & Tech. | 23.175453 | 95,531,149 |
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From Biology-Online Dictionary
(Science: zoology) An order of worms, having a long, round, and generally smooth body; the roundworms. They are mostly parasites. Called also Nematodea, and nematoda.
The trichina, stomach worm, and pinworm of man belong to this group. See also vinegar eel, under Vinegar, and gapeworm.
Origin: NL, fr. Gr, thread. | <urn:uuid:80ec0f3e-4939-4b4b-a502-d9418940e6ff> | 3 | 124 | Structured Data | Science & Tech. | 59.119152 | 95,531,153 |
Heidelberg chemists compare gold, silver and copper atoms in compounds with otherwise identical structures
Some fundamental properties of the coinage metal elements gold, silver and copper, such as chemical behaviour or colours, are already predetermined in their atoms. The unique properties of gold can be largely explained by Albert Einstein’s theory of relativity.
Chemists from Heidelberg University have been able to demonstrate this through their investigations of gold, silver and copper carbenes. They examined only single atoms of each metal in order to compare the three elements. The results of this research, led by Prof. Dr. Bernd Straub, were published in both the German and international editions of the journal “Angewandte Chemie” for applied and fundamental chemistry.
The properties of chemical elements are recurring periodically, since related elements possess the same number of electrons in the relevant outer shell and differ only due to additional inner electron shells. Copper, silver and gold belong to such a group of related elements.
“Comparing copper metal, silver metal and gold metal with their numerous neighbouring metal atoms has never been a problem, as pure metals have been around for millennia,” explains Prof. Straub, a lecturer and researcher at the Institute of Organic Chemistry. However, he and his team were able to ascertain the differences of single atoms – in an otherwise identical molecule with which the metal atoms interact very strongly with a carbon atom via double bonds.
The Heidelberg scientists started their investigations with gold carbenes, which comprise a usually unstable – because highly reactive – double bond between carbon and gold. However, using a chemical “trick”, Prof. Straub and his team found a way to obtain and to isolate a stable gold carbene complex for research purposes. In further steps they managed to prepare and characterise a copper carbene and a silver carbene with otherwise identical structure, even though both these compounds were much more sensitive and unstable than the gold carbene.
Nevertheless, these complexes enabled the scientists to make a detailed comparison of the three elements of the coinage metal group – copper, silver and gold – on the scale of a molecule. Through the crystallisation of the particularly unstable silver carbene, they were able to determine the bond length between silver and the doubly-bonded carbon via an x-ray structural analysis. They then compared this with the shorter, stronger bonding between gold and carbon.
From their observations the researchers conclude that the properties of gold are fundamentally determined by “relativistic effects”. These effects come into play in physics when a phenomenon can no longer be described as “classical”. In chemistry this applies to the properties of certain elements.
The relativistic effects derive from Albert Einstein‘s theory of relativity with the well-known formula E = mc2 by which Einstein established a connection between energy, mass and speed of light. “Of the stable elements, the predicted relativistic effects are most noticeable with gold,” says Prof. Straub. A well-known example is the striking difference in colour between yellow gold metal and colorless silver metal.
Bernd Straub explains that, due to the attraction of the 79-fold positively charged gold nucleus, negatively charged gold electrons achieve such high velocities close to the speed of light (c) that additional motion energy (E) cannot substantially increase their speed. Instead, these electrons increase their mass (m). This effect is seen in the outermost electron shell, which is active and thus responsible for chemical behaviour, colours and properties of coinage metals.
In the case of gold, this leads to a strengthening of its bonds. Gold compounds thereby have a better chance, for example, of activating a triple bond between two carbon atoms. The comparison between the coinage metal elements gold, silver and copper with the double-bond carbon in each case showed that the atomic behaviour of gold is more similar to copper than to silver, although silver is its direct neighbour in the periodic system.
The research findings of the Heidelberg chemists confirm that Einstein‘s theory of relativity does not just play a crucial role in astronomy and space travel with their huge distances. Prof. Straub also emphasises its significance in the world of electrons, atoms and molecules.
M.W. Hussong, W.T. Hoffmeister, F. Rominger, B.F. Straub: Copper and Silver Carbene Complexes without Heteroatom-Stabilization: Structure, Spectroscopy, and Relativistic Effects. Angewandte Chemie International Edition 2015, 54, 10331-10335, doi: 10.1002/anie.201504117
Prof. Dr. Bernd F. Straub
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To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
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Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
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6 July 2011
Ethane lakes in a red haze: Titan’s uncanny moonscape
See more: “Weather round-up for the solar system“
Skies like a bad day in LA, red-and-black rainbows, Mississippi-style river channels – Saturn’s largest moon is our prototype weird-world exoplanet
SUMMERTIME is on its way. A thick smog hangs in the air. Storms are on the move, bringing rare rains to dry areas, and elsewhere lakes are shrinking. Only this is not Earth. This is the view on Saturn’s largest moon, Titan, more than a billion kilometres away.
We knew very little about this strange world before NASA’s Cassini spacecraft arrived at Saturn seven years ago. Since then, the ringed planet has completed a quarter of an orbit around the sun and Titan has passed through its spring equinox. In that time, Cassini has swooped by Titan almost 80 times and has released the Huygens lander onto its surface.
Together they have penetrated the haze that hides Titan’s surface to reveal modest mountains, vast fields of sand dunes, rocks, and even streams, lakes and weather.
Titan looks surprisingly familiar, although it is a cold, dimly lit world made from unfamiliar materials, says planetary scientist Elizabeth Turtle of Johns Hopkins University Applied Physics Laboratory in Baltimore, Maryland. “The rocks are water ice and the lakes are methane and light hydrocarbons, yet we see processes very similar to what we see on Earth.”
So far, there are no recognisable signs of organic life. That’s not surprising: by terrestrial standards, Titan is a deep freeze with surface temperatures at a chilly -180°C. Yet Titan is very much alive in the sense that its atmosphere and surface are changing before our eyes. Clouds drift through the haze and rain falls from them to erode stream-like channels draining into shallow lakes. Vast dune fields that look as if they were lifted from the Sahara sprawl along Titan’s equator, yet the dark grains resemble ground asphalt rather than sand. It is a bizarrely different world that looks eerily like home. Or as planetary scientist Ralph Lorenz puts it: “our prototype weird-world exoplanet”.
By exploring Titan, we can hope to understand more about planets around other stars. NASA’s Kepler telescope has found over 1200 possible exoplanets and we would dearly love to find out what these worlds are like. So far our understanding of geological processes, such as how the landscape is sculpted by winds and waves, is based on empirical evidence from just one planet – our own. That means any explanation of the underlying processes either on other planets or on a changing Earth are beyond us. “If we can test theories on both Earth and Titan, we can be much more confident in extending these theories to other conditions,” says Lorenz, who is also at Johns Hopkins.
What an atmosphere
Titan was discovered in 1655 by Christiaan Huygens. At about 5150 kilometres across, it is slightly larger than the planet Mercury and a touch smaller than Jupiter’s largest moon Ganymede. But what sets it apart from other large moons is its atmosphere, discovered in 1944 by Gerard Kuiper. Wisps of gas surround some satellites, but Titan’s atmosphere is the real thing – and is many times thicker than Earth’s.
This atmosphere made Titan a uniquely tempting target when spacecraft began exploring the solar system. Pioneer 11 took the first snaps in September 1979 and Voyager 1 travelled within 22,000 kilometres of Titan a year later. The results were spectacular, but disappointing: a beautiful high-altitude blue haze hanging over a thick orange haze that obscured the surface. NASA and the European Space Agency soon began planning the Cassini mission to get a closer look.
Cassini finally arrived in 2004, after a seven-year journey from Earth, and released the Huygens lander. This transmitted images and data for 2.5 hours as it descended through Titan’s murky atmosphere and for 1.5 hours after landing. Cassini has continued to monitor Titan ever since, flying past as low as 880 kilometres above its surface. With each pass, Cassini reveals a little more about the only body in the solar system besides the Earth known to have liquid on its surface.
The picture we have built up is intriguing. Like Earth’s atmosphere, Titan’s is largely nitrogen plus one more-reactive compound and some trace gases (see diagram). Titan’s weaker gravity lets its atmosphere extend far higher than on the Earth, with the stratosphere starting at 40 kilometres and reaching up to a few hundred kilometres.
Standing on Titan, you would see a dense orange haze similar to a really bad smog day in Los Angeles. It comes from the same basic process, too – photochemical reactions in the air. LA’s smog is caused by sunlight driving chemical reactions between oxygen, nitrogen compounds and hydrocarbons in the lower atmosphere. On Titan the photochemistry starts at the top of the atmosphere, about 1000 kilometres up, where energetic ultraviolet photons from the sun and cosmic rays trigger reactions among methane and nitrogen molecules. That produces hydrocarbons and cyanide compounds, which drift downwards and react further to produce a poorly understood group of complex compounds called tholins.
Carrie Anderson, who is trying to pin down the composition of these compounds by reproducing them at NASA’s Goddard Space Flight Center, calls them “gunk”.
Tholins aggregate into aerosols that settle slowly into the lower atmosphere, forming a thick layer that blocks solar ultraviolet and affects air circulation and the weather. The particles continue growing and eventually settle on the surface, where they are stable in Titan’s nitrogen-methane atmosphere. Tholins may have rained down on the early Earth as well, but they haven’t been stable here since oxygen became common more than 2 billion years ago and destroyed them.
How Titan sustains such an atmosphere remains a mystery. Photochemical reactions would deplete the methane in Titan’s atmosphere within 15 million years, so something must be replacing the destroyed gas. Vents, geysers or volcanoes could be belching out methane from inside the moon, and Cassini’s radar has spotted landforms that might be icy volcanoes. “It seems unlikely the releases of methane are perfectly timed to match photochemical depletion,” says Lorenz. Surplus methane could have changed Titan’s climate, not least because methane can condense and fall as rain on this chilly world. Giant sporadic releases of methane could mean that Titan is a much wetter place from time to time.
Before Cassini, we expected Titan to be covered with large lakes. However radar observations have shown that lakes cover only a few per cent of the surface and are concentrated near the poles, making Titan much drier than Earth. Yet Cassini has also spotted channels leading into these wet areas, which look as though they were carved by rivers.
Still, Turtle has seen no evidence of year-round rivers, suggesting Titan might resemble the deserts of the US Southwest, where river channels are dry most of the year but carry water during rare rains. Or it could mean the moon was wetter in the past.
Even though we have not seen it directly, Cassini has given us tantalising evidence of rain. Last September, the orbiter studied the equatorial zone, where large sinuous channels wind near dune fields. On previous fly-bys, this region had been covered with clouds. This time, images showed that large areas near the dunes had darkened. A few weeks later, another fly-by revealed that much of the surface had returned to normal. The findings led Turtle’s group to report that methane rain – dubbed “April showers” by the team – had soaked the area and the fluid had evaporated or soaked into the ground (Science, vol 331, p 1414).
The fly-by showed that Titan had experienced its own version of April showers. Methane rain had soaked the surface
“Raindrops on Titan presumably look much like raindrops on Earth,” Turtle says. But with Titan’s weaker gravity, the drops might grow larger and fall more slowly. Many could evaporate as they pass through the dry lower atmosphere and never reach the surface.
If we were to visit Titan, though, rainy days would be very different from those on Earth. For a start, the thick haze blocks most sunlight from reaching the surface. Only longer, red wavelengths would illuminate the landscape. If sufficient sunlight reached falling droplets of methane to make a rainbow, it would appear as a series of red and dark bands.
Now the seasons are changing on Titan as Saturn continues its 29.5 year orbit around the sun. “We are seeing meteorological activity at low latitudes and we expect it to move to high latitudes,” says Turtle. Again the spotlight will be on Titan’s lakes.
The lakes pose their own puzzles, starting with how much liquid they contain. “It’s hard to constrain the depths of the lakes because we’re just seeing the surface,” says Turtle. A few clues come from sprawling Ontario Lacus in the south, which has shrunk several kilometres in some areas since Cassini’s arrival. Oded Aharonson‘s group at the California Institute of Technology in Pasadena estimates the lake level is dropping by about a metre every terrestrial year, suggesting part of the lake bed must be very flat.
What makes Titan’s equivalent of the water cycle so complex is the blend of hydrocarbons in the lakes. That too is something of a mystery. Cassini has identified ethane in Ontario Lacus, and methane is almost certainly present. Methane rain should fall on the lakes but it is vastly more volatile than ethane and propane, so it probably evaporates much faster from lakes, leaving the heavier hydrocarbons behind. Still, confirming this is difficult, says Turtle, “because there’s so much methane in the atmosphere and so many hydrocarbons coating everything”.
Perhaps the best estimate so far comes from Daniel Cordier of the University of Rennes 1 in France, whose computer model incorporates Cassini observations and chemical data to show that three-quarters of an average polar lake is ethane, with 10 per cent methane, 7 per cent propane and smaller amounts of hydrogen cyanide, butane, nitrogen and argon. “The chemical composition probably varies from one particular lake to another,” says Cordier, though his model is too simplistic to see such differences. That’s likely to mean lake-to-lake variations in properties like viscosity. Some might end up as tarry as the Great Salt Lake in Utah is salty.
The changing seasons could solve another mystery. Were you to stand on the shores of one of Titan’s lakes, you would see it was as calm as a millpond. “We haven’t seen any evidence of waves,” Turtle says. That’s puzzling because mixtures of methane and ethane should be less viscous than water, meaning that even light winds can whip up waves. Yet the lakes are eerily flat, to within millimetres.
Standing on the shores of Titan’s hydrocarbon lakes, you would see they are as calm as millponds
Last year, Lorenz calculated that wind speeds of less than 1 metre per second – calm by terrestrial standards – should be sufficient to produce detectable waves in an ethane lake. The fact that we haven’t seen any points either to viscous lakes containing heavier hydrocarbons, as Cordier suspects, or an almost windless Titan. Lorenz’s work also suggests that the wind speeds should pick up as the seasons change, so we may just need to wait for the answers.
The hydrocarbon lakes are part of a landscape that exhibits both the general principles of geology and the different ways they work on other worlds. On Earth, lakes and ponds are tied to aquifers, layers of permeable rock that can store water. So might hydrocarbons permeate Titan’s rock-ice, linking its methane-ethane lakes to “methanofers”?
Lakes near the north pole have not changed in years of observations, Turtle says. Those in the south, in contrast, show some evaporation at times, implying that they are sitting on impermeable layers. Perhaps the northern lakes do not drain away because they are in contact with larger reservoirs of ground methane.
Perhaps the most striking similarity between Earth and Titan was presented earlier this year at the Lunar and Planetary Science Conference in The Woodlands, Texas. Mike Malaska is an organic chemist whose day job is drug discovery for a small pharmaceutical company but whose passion has become exploring Titan’s surface. Malaska works as a volunteer for the Cassini team in his spare time and at the conference he described a winding channel flowing into a south Titan lake that follows a path very similar to a stretch of the lower Mississippi river – and thus might carry a comparably vast flow after a methane rain.
Even Titan’s rocks have that mix of sameness and difference. They are made of water ice, which on the frigid satellite should be about as resistant to erosion as terrestrial minerals. Pictures from Huygens show cobbles of ice that resemble water-worn rocks on a terrestrial stream bed.
The same goes for the sand dunes that cover about 20 per cent of Titan’s surface. They appear uncannily alike in size and shape to dune fields in the Sahara, Namibia and Saudi Arabia. “The dunes were a surprise to everyone,” says Jani Radebaugh of Brigham Young University in Provo, Utah. Dunes form on Earth when suitable winds scatter sand-sized grains – usually quartz, gypsum or basalt – across the surface, creating ridges that grow to enormous sizes. The grains need to be a particular size, but not a particular composition.
On Titan, the grains are composed of tholins from the hazy atmosphere, which according to models and observations of the dunes’ shape, are blown by strong winds when the sun is over the equator. Radebaugh thinks the compounds formed layers on the surface possibly in much the way that carbonates form limestone layers in shallow Earth seas. Methane rains then eroded these layers, forming sand-sized particles.
In the absence of any mission to bring back samples from Titan, Radebaugh says laboratory studies are needed to determine the particles’ interaction with methane-based fluids, how they create landforms, and to work out their composition.
The Cassini team hopes that many of Titan’s puzzles will be solved as Saturn journeys around the sun. “Hopefully the mission will extend to the northern summer solstice in 2017,” says Turtle. That would cover seasonal changes in climate, lakes and atmospheric circulation vital to understanding Titan as a whole.
And plans are already afoot for a follow-on mission called the Titan Mare Explorer (TiME), which NASA could launch in 2016. The probe is destined to splash down on one of the largest bodies of liquid so far identified on Titan, a 10,000-square-kilometre hydrocarbon sea called Ligeia Mare. It would spend three to six months cruising the northern lake, analysing its composition and exploring the vicinity.
By then we will have confirmed the existence of many more planets around other stars. Some of them will have thick atmospheres; all will be too distant for us to travel to any time soon. Yet thanks to what we’ll have learned from Titan, these strange worlds may not be so alien after all.
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Bizarre chemical discovery gives homeopathic hint | <urn:uuid:54ae0f6f-0856-456c-ba66-827e985c7292> | 3.484375 | 3,451 | Truncated | Science & Tech. | 44.88535 | 95,531,176 |
Distribution of dissolved gas in water and bubbles in ice upon movement of a crystallization front
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The distribution of dissolved gas in water upon increase in a crystallization front is considered. Optimal conditions are derived for water crystallization, under which the gas-bubble distribution in the ice formed will be the most homogeneous.
KeywordsCrystallization Statistical Physic Optimal Condition Water Crystallization Crystallization Front
Unable to display preview. Download preview PDF.
- 1.L. G. Kachurin and V. G. Morachevskii, Kinetics of Water Phase Transitions in the Atmosphere [in Russian], LGU (1965).Google Scholar
- 2.W. A. Murray and R. J. List, Glaciology,11, No. 63 (1972).Google Scholar
- 3.H. S. Carslaw and J. C. Jaeger, Conduction of Heat in Solids, 2nd ed., Oxford University Press (1959).Google Scholar
- 4.M. A. Lavrent'ev and B. V. Shabat, Methods in the Theory of Functions of a Complex Variable [in Russian], GIFML, Moscow (1958).Google Scholar | <urn:uuid:d2ed84eb-913f-4a88-a3b0-9b559a7e98fd> | 2.53125 | 257 | Academic Writing | Science & Tech. | 60.772769 | 95,531,185 |
Perimeter of a rectangle
If the perimeter of a rectangle is 114 meters and the length is twice the width plus 6 meters, what are the length and width?
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If water flows into the pool by two inlets, fill the whole for 18 hours. First inlet filled pool 10 hour longer than second. How long pool is filled with two inlets separately? | <urn:uuid:dcfaf2e4-55e2-438f-9074-bf15d56aac37> | 3.390625 | 774 | Tutorial | Science & Tech. | 87.557631 | 95,531,222 |
Creating the HTML Form
If you need a refresher on how to properly make an HTML form, check out the HTML Form Lesson before continuing on.
We first create an HTML form that will let our customer choose what they would like to purchase. This file should be saved as “order.html”
<html><body> <h4>Tizag Art Supply Order Form</h4> <form> <select> <option>Paint</option> <option>Brushes</option> <option>Erasers</option> </select> Quantity: <input type="text" /> <input type="submit" /> </form> </body></html>
Tizag Art Supply Order Form
Remember to review HTML Forms if you do not understand any of the above HTML code. Next we must alter our HTML form to specify the PHP page we wish to send this information to. Also, we set the method to “post”.
<html><body> <h4>Tizag Art Supply Order Form</h4> <form action="process.php" method="post"> <select name="item"> <option>Paint</option> <option>Brushes</option> <option>Erasers</option> </select> Quantity: <input name="quantity" type="text" /> <input type="submit" /> </form> </body></html>
Now that our “order.html” is complete, let us continue on and create the “process.php” file which will process the HTML form information.
PHP Form Processor
We want to get the “item” and “quantity” inputs that we have specified in our HTML form. Using an associative array (this term is explained in the array lesson), we can get this information from the $_POST associative array.
The proper way to get this information would be to create two new variables, $item and $quantity and set them equal to the values that have been “posted”. The name of this file is “process.php”.
<html><body> <?php $quantity = $_POST['quantity']; $item = $_POST['item']; echo "You ordered ". $quantity . " " . $item . ".<br />"; echo "Thank you for ordering from Tizag Art Supplies!"; ?> </body></html>
As you probably noticed, the name in $_POST[‘name‘] corresponds to the name that we specified in our HTML form.
Now try uploading the “order.html” and “process.php” files to a PHP enabled server and test them out. If someone selected the item brushes and specified a quantity of 6, then the following would be displayed on “process.php”:
You ordered 6 brushes. Thank you for ordering from Tizag Art Supplies!
PHP & HTML Form Review
A lot of things were going on in this example. Let us step through it to be sure you understand what was going on.
- We first created an HTML form “order.html” that had two input fields specified, “item” and “quantity”.
- We added two attributes to the form tag to point to “process.php” and set the method to “post”.
- We had “process.php” get the information that was posted by setting new variables equal to the values in the $_POST associative array.
- We used the PHP echo function to output the customers order.
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2006 January 4
Explanation: Fading sunlight, a young crescent Moon, and brilliant Venus shared the western sky in this view of 2005's final sunset from the top of Mount Haleakala, on Maui, Hawaii. Also known as the Sacred House of the Sun, Haleakala, is Maui's dormant volcano. At 10,000 feet the summit is an ideal site for astronomical observatories, and this scene also features the silhouette of the northern hemisphere Faulkes Telescope. Of particular interest to students the Faulkes Telescope is a 2-metre diameter instrument, dedicated to astronomy education, that can be remotely operated over the internet. The project is a joint effort between the Dill Faulkes Educational Trust and the University of Hawaii Institute for Astronomy. Of course on Haleakala, "Happy New Year" would be "Hauoli Makahiki hou" (how-oh-lee ma-ka-hee-key ho).
Authors & editors:
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: EUD at NASA / GSFC
& Michigan Tech. U. | <urn:uuid:a7257468-8f0b-4fac-bcaa-e997673b0937> | 3.171875 | 243 | Knowledge Article | Science & Tech. | 41.45456 | 95,531,267 |
When it comes to renewable energy, the benefits extend beyond just literally helping the environment. For example, over the span of increased installations of wind and solar power since 2007, it’s improved air quality everywhere. Based on an analysis report by Nature Energy, those advantages could have saved up to 12,700 lives in the United States.
A number of researchers evaluated the climate and benefits of wind and solar generation in a period between 2007 and 2015. Over that time, generation has grown from 35,000 gigawatt-hours to an enormous 227,000 gigawatt-hours, over a 73 percent increase in eight years. California used to be a renewable generation powerhouse, but especially in the solar industry their share has dropped compared to other regions from 87 percent to 63 percent.
Not only did emissions saved from sustainable energy generation produce up to $107.9 billion in the study period, but up to 12,200 people avoided an early death from wind generation itself. Anywhere from 100 to 500 people were saved thanks to solar energy. At the very least, the study suggests that over 3,000 people benefitted from better air quality.
Nearly a 10,000-people difference is a pretty large range, but it’s hard to exactly determine how many lives would be lost. Different locations had different results in terms of air benefits, and California had the smallest benefit with so much smog congesting their bigger urban areas. The Mid-Atlantic states -- Pennsylvania, Virginia, West Virginia, Maryland, and Delaware -- “saw the largest air quality and climate wind benefits” according to the report.
These figures were determined by how much emissions were avoided from not only carbon dioxide, but also sulfur dioxide, nitrogen oxides, and atmospheric particulate matter. The first three’s avoided emissions have ramped up considerably in wind and solar. For example, over 22.3 million metric tons of CO2 emissions were eliminated in 2007 compared to a whopping 147 million avoided in 2015.
That hasn’t been the same for particulate matter, which has gone up and down over the years. Tons of small inhalable particles that measure in at 2.5 micrometers or smaller can get into people’s lungs. The smaller these are, the further they can get into the system and create issues like irregular heartbeat, breathing issues, and heart attacks. Particles have gone down from wind generation since 2011, and finally solar energy saw a decrease from 2014 to 2015.
In good news, the overall air quality has improved from 2000 to 2016. According to the EPA, there’s been a 42 percent decrease in PM2.5 in the United States. Both the Ohio Valley and Southeast regions of the country have seen the most decrease with 48 percent.
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When localizing the text in your app, you may come across cases where your new languages are structured differently than you're used to. In this video, review how to use string placeholders and Android plural resources to support these differently structured languages.
- [Instructor] The first thing most people think of when localizing an app is translating the text. We've talked a bit about externalizing our strings already. Well let's take a look at some other things to consider when preparing these strings for translation. Often your text will need to be dynamic in response to something custom in your application. In our local news app let's click on one of these articles and we can see on this article page we have a string that says published on October 5, 2017. We might implement that by adding a string that says published on with a space at the end of it and then concatenate the date to the end of that string for display, but that structure isn't consistent across all languages.
For example, in Hindi the date would go at the front of the phrase. So we can add this flexibility with formatting place holders. So let's go into Android Studio and we'll open the article activity. So here we can see that we are setting the text on the article date text view. We can see that there are actually two different errors. One is the hard code to string error and one is the place holder error. So let's fix both of them. We'll open the strings file and it's easy to jump to it by using the shortcut Command + Shift + O and if you type in strings.xml you'll see all of your strings files and make sure to select your default strings file.
Now let's add a new string towards the bottom of the file here on line 22. We'll call it published on and we'll make the text published on and here we need our place holder. The place holder is percent one dollar sign S. So it's made up of two parts, the index and the format type. The index, which is the percent one part, it indicates the order of the arguments and this string since there's only one argument it may not make a lot of sense, but it's required.
It let's you change the order around in different languages in cases where you may need to do that. And the second part is the format type. We're passing a string in, so we're going to use S, but you could use F for floating point or D for an integer value. Back in the code to get the argument passed into the string we have to use the get string method. So we'll go into set text and we'll replace what we have here with get string, the resource identifier for the string that we just created, published on and then pass in the date as the second parameter to this get string method.
So I'm going to delete the hard coded string and leave the date formatting there and scroll all the way to the end to make sure we have our all of our parenthesis that we need. Now we don't see the lint error anymore. If we run the program and go back into the article page we can see the date still shows up as expected. You might also want to use a formatting place holder for inserting numbers. On the same article screen here we display the comment count for an article, but it's a little more complicated if there's only one comment you'd want to say one comment, and if there are more than one comments you'd want to say five comments with an s.
This is handled in android with plural strings. Now this pluralization rule I just mentioned of one comment versus multiple comments is not universal across all languages. In Chinese for example, there is not distinction between one or many. In other languages zero is a special case that must be handled separately. Some of these distinctions are isolated to languages that you may not support initially, so rely on your translators to help make the distinction of what should and shouldn't be supported.
In Android plural strings are a different resource from regular strings. In Android Studio let's go ahead and open up the plurals.xml file. You can find that in the resources directory and then under values. Right here next to the strings file is plurals.xml. I've gone through and added details for each of the options, but the ones you'll most likely want to focus on are one, here on line eight and other here on line 21. I've added the strings for the different comment options, so let's go ahead and implement this in our code.
So back in article activity.java here where we're loading the comment count we can see we're getting the article comment count and we're just appending comments to the end of it. So let's go ahead and create a new variable to make it a little easier to read. We'll create a string and we'll call it comment count. To get access to the plurals we have to get the resources object, which is available in our activity, so we'll call get resources and then the method is called get quantity string, and it takes three parameters.
The first is the reference to the plurals resource, which ours is called comments, and then the second is going to be the number that's used to select which plural value to provide. In our case it is the article comment count. So article data.get article comment count. Then it also takes in a third parameter and the third parameter is used for our formatting string. So we're going to pass the exact same thing in.
The first time we pass the comment count in is to select the string that's used to display and that's to distinguish between comment and comments. The second time we pass it in is used to replace our place holder so the number is added to the beginning of the string. Again, we'll pass in article data.get article comment count. So now we've created that string and we'll replace the set text method call instead of the concatenation with the comment count text that we added.
So let's go ahead and run the app again. We'll click on the first article and here we can see it still says 124 comments and if we go back and go to a different article, the dog park article, we can see that this article only has one comment. Both of these recommendations may see like overkill if you're just targeting one language, but setting up string place holders and plural strings ahead of time will make any future localization a lot easier.
- The localization process
- Basic internationalization
- Choosing target markets
- Preparing your app for internationalization
- Translating your app
- Testing and releasing your translated app | <urn:uuid:8ef487ff-4ed7-4f56-a831-7f647487606c> | 3.078125 | 1,376 | Tutorial | Software Dev. | 63.38553 | 95,531,324 |
What it does
When using the PyBuilder, every project needs to be initialized. After checking out the project, you need to
- Create a virtual environment.
- Activate the virtual environment.
- Install the pybuilder in the virtual environment.
- Install the project dependencies in the virtual environment.
- Run pyb to build and test your project.
This program is an attempt at making these routine operations dead simple and time-efficient. Note that virtual environments are always created with the --clear flag, meaning you can run pyb-init to reset your virtual environment, for example after changing a dependency.
sudo pip install pyb_init
Checkout from GitHub
pyb-init github user : project
pyb-init git GIT_URL
pyb-init svn SVN_URL
Initialization from local project
When in the project root, run
Customization of the generated environment
You can override the default name of the virtualenv with
Also, you can include your systems's site-packages in the virtualenv (for OS-packaged bindings like YUM, etc..) with the flag
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Stephen Hawking · Danger Quotes
The danger is that global warming may become self-sustaining, if it has not done so already. The melting of the Arctic and Antarctic ice caps reduces the fraction of solar energy reflected back into space, and so increases the temperature further. Climate change may kill off the Amazon and other rain forests, and so eliminate once one of the main ways in which carbon dioxide is removed from the atmosphere. The rise in sea temperature may trigger the release of large quantities of carbon dioxide, trapped as hydrides on the ocean floor. Both these phenomena would increase the greenhouse effect, and so global warming further. We have to reverse global warming urgently, if we still can.
As scientists, we understand the dangers of nuclear weapons and their devastating effects, and we are learning how human activities and technologies are affecting climate systems in ways that may forever change life on Earth. As citizens of the world, we have a duty to alert the public to the unnecessary risks that we live with every day, and to the perils we foresee if governments and societies do not take action now to render nuclear weapons obsolete and to prevent further climate change...There’s a realization that we are changing our climate for the worse. That would have catastrophic effects. Although the threat is not as dire as that of nuclear weapons right now, in the long term we are looking at a serious threat.
At a press conference for the Bulletin of the Atomic Scientists (2007-01-17)
More Danger Quotes...
Stephen William Hawking, CH, CBE, FRS (born 1942-01-08) is a British theoretical physicist.
» British Quotes
» Quotes by Physicists
Sources by Stephen Hawking
A Brief History of Time
The Beginning of Time
Newton's Principia, 300 Years of Gravitation
The Notebooks of Leonardo da Vinci
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Neuroscientist David Linden notes that there is a tendency to be awed by the abilities of the human brain in his brain engineering speech. Though evolution has managed to create some amazing feats geared towards our survival—for instance, the pleasure circuits of our brain are adapted to let us enjoy eating, drinking and copulation, and linking these pleasure circuits to social cognition functions promote group cohesion.
However, Linden is quick to mention that the brain is not the most effectively constructed. In fact, he refers to the evolution process itself as a "tinkerer" rather than an engineer. This means that it focuses on solving problems as they come, rather than looking at all possible contingencies for the most effective composition. The brain is ultimately more of a mess than one might initially think, especially considering the fact that we possess two visual and two audio systems (unconscious and conscious.) However, this does not mean that it does not function well; it merely means that not everything is necessarily adaptive or useful, and that our brains are receptive to cultural and behavioral impact.
Insufficient Brain Engineering
More Stats +/-
The Neuroscience of Love
The Pleasure of Uncertainty
Where Creativity Comes From
The Process of Feeling
Researching Human Behavior
David Linden Keynotes
Keynotes by David Linden discuss how the human brain and body react pleasurably to uncertain and...
The David Linden Brain Engineering Speech Explains Our Messy Nature
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Pathways & interactions
RNA-directed RNA polymerase, negative-strand RNA virus (IPR007099)
Short name: RNA-dir_pol_NSvirus
Overlapping homologous superfamilies
RNA-directed RNA polymerase (RdRp) (EC:18.104.22.168) is an essential protein encoded in the genomes of all RNA containing viruses with no DNA stage [PMID: 2759231, PMID: 8709232]. It catalyses synthesis of the RNA strand complementary to a given RNA template, but the precise molecular mechanism remains unclear. The postulated RNA replication process is a two-step mechanism. First, the initiation step of RNA synthesis begins at or near the 3' end of the RNA template by means of a primer-independent (de novo) mechanism. The de novo initiation consists in the addition of a nucleotide tri-phosphate (NTP) to the 3'-OH of the first initiating NTP. During the following so-called elongation phase, this nucleotidyl transfer reaction is repeated with subsequent NTPs to generate the complementary RNA product [PMID: 11531403].
All the RNA-directed RNA polymerases, and many DNA-directed polymerases, employ a fold whose organisation has been likened to the shape of a right hand with three subdomains termed fingers, palm and thumb [PMID: 9309225]. Only the catalytic palm subdomain, composed of a four-stranded antiparallel beta-sheet with two alpha-helices, is well conserved among all of these enzymes. In RdRp, the palm subdomain comprises three well conserved motifs (A, B and C). Motif A (D-x(4,5)-D) and motif C (GDD) are spatially juxtaposed; the Asp residues of these motifs are implied in the binding of Mg2+ and/or Mn2+. The Asn residue of motif B is involved in selection of ribonucleoside triphosphates over dNTPs and thus determines whether RNA is synthesised rather than DNA [PMID: 10827187]. The domain organisation [PMID: 9878607] and the 3D structure of the catalytic centre of a wide range of RdPp's, even those with a low overall sequence homology, are conserved. The catalytic centre is formed by several motifs containing a number of conserved amino acid residues.
There are 4 superfamilies of viruses that cover all RNA containing viruses with no DNA stage:
- Viruses containing positive-strand RNA or double-strand RNA, except retroviruses and Birnaviridae: viral RNA-directed RNA polymerases including all positive-strand RNA viruses with no DNA stage, double-strand RNA viruses, and the Cystoviridae, Reoviridae, Hypoviridae, Partitiviridae, Totiviridae families.
- Mononegavirales (negative-strand RNA viruses with non-segmented genomes).
- Negative-strand RNA viruses with segmented genomes, i.e. Orthomyxoviruses (including influenza A, B, and C viruses, Thogotoviruses, and the infectious salmon anemia virus), Arenaviruses, Bunyaviruses, Hantaviruses, Nairoviruses, Phleboviruses, Tenuiviruses and Tospoviruses.
- Birnaviridae family of dsRNA viruses.
- All positive-strand RNA eukaryotic viruses with no DNA stage.
- All RNA-containing bacteriophages -there are two families of RNA-containing bacteriophages: Leviviridae (positive ssRNA phages) and Cystoviridae (dsRNA phages).
- Reoviridae family of dsRNA viruses.
This entry corresponds to a relatively conserved segment of 147 - 180 aa of RdRp or its catalytic subunit. The proteins in this family are: RNA polymerase PB1 subunits of Orthomyxoviruses and RNA polymerases (L proteins) of Arenaviruses, Bunyaviruses, Hantaviruses, Nairoviruses, Phleboviruses, Tenuiviruses and Tospoviruses.
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The figure A is, of course, a square. Figure B is an oblong, or a rectangle. Figure C is a rhombus. Figure D is a trapezium (also called a trapeze or trapezoid). And figure E is a parallelogram, not defined here.
The only figure defined here that Euclid actually uses is the square. The other names of figures may have been common at the time of Euclid’s writing, or they may have been left over from earlier authors’ versions of the Elements, or they may have been added later.
Euclid makes much use of parallelogram, or parallelogrammic area, which he does not define, but clearly means quadrilateral with parallel opposite sides. Parallelograms include rhombi and rhomboids as special cases. And rather than oblong, he uses the term rectangle, or rectangular parallelogram, which includes both squares and oblongs.
Squares and oblongs are defined to be right-angled. Of course, that is intended to mean that all four angles are right angles. Sometimes these definitions are too brief, but the intended meaning can easily be determined from the way the definitions are used. In particular, proposition I.46 constructs a square, and all four angles are constructed to be right, not just one of them. | <urn:uuid:6e8cb3e3-fbaa-4328-902d-c661f310b988> | 4.4375 | 282 | Academic Writing | Science & Tech. | 44.566294 | 95,531,429 |
Josie Wales, Anti-Media
In the wake of Bitcoin’s meteoric rise in popularity, interest in the dynamics of Bitcoin and other cryptocurrencies has skyrocketed over the past year. With bank-based blockchain projects poised to revolutionize the world of financial services, researchers continue to study the new technology to better understand the inner workings of the blockchain, as well its economic, social, and technological implications.
One such researcher from Stanford University recently uncovered a parallel between cryptocurrency transactions and the structure of swirling liquid that may help develop more advanced digital security, help validate precise procedures used in drug development, and even further our understanding of physical processes in nature.
In a study published recently in PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES, Stanford applied physics doctoral student William Gilpin explains how swirling liquids like coffee follow the same principles as cryptocurrency transactions. Cryptocurrency transactions are encrypted through a complex mathematical function called a cryptographic hash. Hash functions work by “mathematically transform[ing] digital information into a unique output that disguises the input. Hash functions are deliberately designed to be complex, but they also remain consistent so that the same input always produces the same output. However, two similar inputs will likely produce very different outputs.”
Gilpin said he noticed “similarities between the way hash functions work and the physical laws involved with stirring a liquid” and decided to explore it during a winter break.
Focusing on a principle called chaotic mixing, Gilpin found that the equations in mixing a fluid were almost identical to the properties of a hash function. “I wasn’t expecting it to perform that well,” Gilpin said. “When it looked like it satisfied every property of a hash function I started getting really excited. It suggests that there’s something more fundamental going on with how chaotic math is acting.”
In addition to helping develop more secure ways to protect information, this connection could also be used to improve drug development methods that require injecting various fluids at specific points in time, according to Gilpin. “If you don’t form the correct arrangement when you’re done, then you know that one of your processes didn’t go right,” he said. “The chaotic property ensures that you’re not going to accidentally get a final product that looks correct.”
The findings also indicate that cryptographic computations occur not only in the digital world but also in nature. According to Gilpin, “Something as ordinary as a fluid is still performing computations. It’s not something only humans tell computers to do. It’s something that nature does and it shows up in the structure of how things form.”
While Gilpin is not himself a computer scientist or drug developer, he’s excited about the doors this discovery will open in other fields. “Having an actual physical model and showing that this is a naturally occurring process might open up new ways to think about those functions,” he said.
Josie Wales, journalist for Anti-Media, is a writer, public speaker, Youtube personality, and activist from Philadelphia. She is also a tech writer for d10e.co, and formerly worked as editor and contributing writer at The Free Thought Project. Josie covers disruptive technology, artificial intelligence, innovation, tech solutions, and digital privacy issues for Anti-Media. Contact Josie: email@example.com. Support her work on Patreon: patreon.com/JosieWales. | <urn:uuid:0f8d9a91-c40a-4951-856f-09e59a377bc7> | 2.921875 | 739 | Personal Blog | Science & Tech. | 29.21065 | 95,531,445 |
Better Bugs to Make Plastics
OPX Biotechnologies uses genetic engineering to speed the development of organisms that make chemicals and fuel.
A startup that has successfully engineered bacteria to make common industrial chemicals is now using its technology to engineer organisms to make renewable fuel.
OPX Biotechnologies, based in Boulder, Colorado, says its strains of E. coli can be used to convert sugar to acrylic acid–a key component of paints, diapers, and adhesives–at lower costs than making it from petroleum. The bacteria-based process produces 75 percent fewer carbon-dioxide emissions than making the same amount from oil, and a single commercial plant using the process could reduce petroleum consumption by over 500,000 barrels per year.
The technology has been demonstrated in a pilot plant with a 200-liter fermentation tank, and the company plans to build a 20,000 liter system starting next year. Then it plans to build a commercial plant in 2014 that can produce 100 million pounds of acrylic. So far the company has raised $22.4 million of venture capital. The company is also working on a process that employs bacteria to convert carbon dioxide and hydrogen into diesel fuel. The U.S. Department of Energy’s Advanced Research Projects Agency for Energy (ARPA-E) recently gave the company a $6 million grant to demonstrate the technology in a pilot plant within three years.
The company is one of dozens of startups that have sprung up to make chemicals from plant matter rather than petroleum. It’s something researchers have been trying to do for decades, but only recently have they had any success with commercial-scale production. For example, in 2007, DuPont started commercial production of propanediol (used for plastics and cosmetics) made from corn sugar.
OPX’s approach to engineering strains of microorganisms is faster and cheaper than conventional methods, says CEO Charles Eggert. The company has developed a novel way of generating mutations that lets it track which genes are responsible for performance changes. Rather than hoping that all of the best changes are combined at random in a single strain, which is the case with the conventional approach, the OPX researchers use this detailed information to select genetic changes from a variety of randomly created strains and combine them into one.
Commercializing the technology will be challenging. The company still needs to produce acrylic acid at costs at or below the costs for conventional petroleum-based acrylic acid. Eggert says this is possible based on the performance of OPX’s organisms, but costs are often greater than expected. For one thing, it’s difficult for bio-based approaches to produce a product with the 99.99 percent purity levels that industrial customers require, says Robert Kirschbaum, vice president of open innovation at Netherlands-based DSM, a major producer of chemicals, including acrylic acid. If the chemical is not pure enough, a company must buy expensive purification equipment, which throws off its cost estimates.
For its ARPA-E diesel project, OPX is using its technology to engineer a bacteria, cupriavidus necator, to produce fatty acids to make biodiesel. This could be mixed with petroleum-based diesel for use in vehicles. OPX could use carbon dioxide emitted from power plants and hydrogen from a variety of sources, including natural gas. The goal of the ARPA-E project is to use hydrogen generated from renewable sources, such as water splitting using electricity from solar panels.
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Vertices of RT
Show that the points P1 (5,0), P2 (2,1) & P3 (4,7) are the vertices of a right triangle.
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A group of researchers from The Scripps Research Institute has identified a small synthetic molecule that can induce a cell to undergo dedifferentiation - to move backwards developmentally from its current state to form its own precursor cell.
This compound, named reversine, causes cells which are normally programmed to form muscles to undergo reverse differentiation - retreat along their differentiation pathway and turn into precursor cells.
These precursor cells are multipotent; that is, they have the potential to become different cell types. Thus, reversine represents a potentially useful tool for generating unlimited supply of such precursors, which subsequently can be converted to other cell types, such as bone or cartilage.
"This [type of approach] has the potential to make stem cell research more practical," says Sheng Ding, Ph.D. "This will allow you to derive stem-like cells from your own mature cells, avoiding the technical and ethical issues associated with embryonic stem cells."
Jason Bardi | EurekAlert!
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
Pollen taxi for bacteria
18.07.2018 | Technische Universität München
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
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Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Barbara is moving across the Isthmus of Tehuantepec today, May 30. Barbara could regenerate over the Bay of Campeche, on the Gulf of Mexico side of Mexico, and satellite imagery is watching Barbara closely. The Bay of Campeche is surrounded on three sides by the Mexican states of Campeche, Veracruz and Tabasco and is part of the Gulf of Mexico.
The MODIS instrument aboard NASA’s Aqua satellite captured this visible image of Hurricane Barbara as it was making landfall in southwestern Mexico. The image was taken at 19:30 UTC (3:30 p.m. EDT). Credit: NASA Goddard MODIS Rapid Response Team
At 2 p.m. EDT on May 29, Barbara became a hurricane with maximum sustained winds near 75 mph. Just three hours later Barbara was already moving over land. It brought heavy rainfall to eastern Oaxaca and Western Chiapas, Mexico.
The MODIS instrument aboard NASA’s Aqua satellite captured a visible image of Hurricane Barbara as it was making landfall in southwestern Mexico. The image was taken at 19:30 UTC (3:30 p.m. EDT). The image showed a large “tail” of thunderstorms that extended into the eastern Pacific Ocean.
By 8 p.m. EDT Barbara weakened back to tropical storm status as maximum sustained winds dropped to 60 mph. At 11 p.m. EDT, Barbara, still a tropical storm, although weaker was dropping a lot of rain. It was located near 17.1 north and 93.8 west, about 50 miles (85 km) west-northwest of Tuxtla Gutierrez, Mexico.
The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA’s Aqua satellite captured infrared images of Barbara’s cloud top temperatures on May 29 and May 30. The images showed that the interaction with landfall had a large toll on the organization and uplift of air within the storm. In an image from May 29 at 19:23 UTC (3:23 p.m. EDT) Barbara contained a large area of powerful thunderstorms, where cloud top temperatures were as cold as -63F (-52C). Those storms had the potential for heavy rainfall. After Barbara made landfall, AIRS captured another infrared image that showed how the friction of Barbara’s land interaction drastically reduced the uplift and thunderstorm development as cloud top temperatures warmed. The AIRS image, taken on May 30 at 07:35 UTC (3:35 a.m. EDT) showed fragmented strong thunderstorms around the center of circulation, with the largest area over the Gulf of Campeche.
By 5 a.m. EDT on May 30, Barbara weakened to a tropical depression with maximum sustained winds near 35 mph (55 kph). It was centered near 17.8 north and 93.9 west, about 40 miles (60 km) southeast of Coatzacoalcos, Mexico. Barbara is moving to the north at 8 mph (13 kph) and has a minimum central pressure of 1000 millibars. At that time, there were no warnings or watches in effect.
Barbara continues to be a big rainmaker over land. The National Hurricane Center (NHC) expects Barbara to produce total rain accumulations of 6 to 10 inches with isolated maximum amounts of 20 inches possible over portions of southeastern Mexico. The NHC reports that Arriaga, located in the State of Chiapas recorded a rainfall total of 16.02 inches (407 mm) in 18 hours from 11 a.m. EDT on May 29 to 5 a.m. EDT, May 30.
The Independent.ie reported that two people were killed as a result of the storm. A 26 year old Mexican resident was killed in an attempt to cross a rain swelled river and a 61-year-old U.S. man who was surfing at a Salina Cruz beach drowned during the storm.
The National Hurricane Center expects Barbara to keep dropping large amounts of rain over portions of southeastern Mexico today, May 30 as it heads for the Bay of Campeche. Barbara is expected to drop between 6 and 10 inches of rainfall with isolated maximum amounts up to 20 inches today, so inland flooding and mudslides are possible.Text credit: Rob Gutro
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A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
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Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
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Astronomers have found that a planet outside our solar system, which is similar to Saturn in mass and exceeds the size of Jupiter by 20 percent, has an atmosphere free of clouds. The hot gas giant, WASP-96b, periodically transits a Sun-like star 980 light years away in the southern constellation Phoenix.
Using the European Southern Observatory’s Very Large Telescope in Chile, the team studied the atmosphere of WASP-96b when the planet passed in front of its host star. This enabled the team to measure the decrease of starlight caused by the planet and its atmosphere, and thereby determine the planet’s atmospheric composition. “We’ve been looking at more than twenty exoplanet transit spectra. WASP-96b is the only exoplanet that appears to be entirely cloud-free and shows such a clear sodium signature, making the planet a benchmark for characterisation,” said the lead author of the study, Nikolay Nikolov from the University of Exeter in Britain.
Just as an individual’s fingerprints are unique, atoms and molecules have a unique spectral characteristic that can be used to detect their presence in celestial objects. The spectrum of WASP-96b shows the complete fingerprint of sodium, which can only be observed for an atmosphere free of clouds, according to the study published in the journal Nature.
It has long been predicted that sodium exists in the atmospheres of hot gas-giant exoplanets, and in a cloud-free atmosphere, it would produce spectra that are similar in shape to the profile of a camping tent. “Until now, sodium was revealed either as a very narrow peak or found to be completely missing. This is because the characteristic ‘tent-shaped’ profile can only be produced deep in the atmosphere of the planet and for most planet clouds appear to get in the way,” Nikolov added.
Clouds and hazes are known to exist in some of the hottest and coldest solar system planets and exoplanets. The presence or absence of clouds and their ability to block light plays an important role in the overall energy budget of planetary atmospheres. “It is difficult to predict which of these hot atmospheres will have thick clouds. By seeing the full range of possible atmospheres, from very cloudy to nearly cloud-free like WASP-96b, we’ll gain a better understanding of what these clouds are made of,” explains study co-author Jonathan Fortney, Professor at University of California, Santa Cruz. | <urn:uuid:9ad03188-0489-4b2f-96b6-db8e00464bfc> | 3.625 | 524 | News Article | Science & Tech. | 36.077468 | 95,531,540 |
Washington: New images taken from NASA's Chandra X-ray Observatory show a spectacular jet that emanates from a black hole in the centre of the galaxy and extends across 300,000 years toward a brilliant hotspot and a counter jet pointing in the opposite direction.
The Pictor A galaxy is located nearly 500 million light years from Earth and contains a supermassive black hole at its centre.
A huge amount of gravitational energy is released as material swirls towards the event horizon, the point of no return for infalling material.
This energy produces an enormous beam, or jet, of particles travelling at nearly the speed of light into intergalactic space.
To obtain images of this jet, scientists used Chandra observatory at various times over 15 years.
The jet in Pictor displays continuous X-ray emission over a distance of 300,000 light years.
By comparison, the entire Milky Way is about 100,000 light years in diameter.
Because of its relative proximity and Chandra’s ability to make detailed X-ray images, scientists can look at detailed features in the jet and test ideas of how the X-ray emission is produced.
In addition to the prominent jet seen pointing to the right in the image, researchers report evidence for another jet pointing in the opposite direction, known as a "counterjet".
While tentative evidence for this counterjet had been previously reported, these new Chandra data confirm its existence.
The detailed properties of the jet and counterjet observed with Chandra show that their X-ray emission likely comes from electrons spiraling around magnetic field lines, a process called synchrotron emission.
In this case, the electrons must be continuously re-accelerated as they move out along the jet. How this occurs is not well understood.
A paper describing these results is forthcoming in the journal Monthly Notices of the Royal Astronomical Society.
Updated Date: Feb 03, 2016 23:01 PM | <urn:uuid:d6ac0f9e-73bd-4556-b599-0dd5138347e9> | 3.640625 | 394 | News Article | Science & Tech. | 38.375839 | 95,531,555 |
Two NASA satellites provided data on clouds, rainfall and the diameter of the eye of Super Typhoon Vongfong as it turned north in the Northwestern Pacific Ocean.
Typhoon Vongfong formed on October 2, 2014 southeast of Guam. Typhoon Phanfone, that recently pummeled Japan, formed near the same area in the western Pacific Ocean.
On Oct. 8 at 02:15 UTC (Oct. 7 at 10:15 p.m. EDT), NASA's Terra satellite captured this view of the wide circular eye in Super Typhoon Vongfong in the Philippine Sea.
Image Credit: NASA Goddard MODIS Rapid Response Team
Vongfong had wind speeds of about 120 knots (138 mph) when the Tropical Rainfall Measuring Mission or TRMM satellite flew above the intensifying typhoon's eye on October 7, 2014 at 0800 UTC (4 a.m. EDT).
TRMM's Precipitation Radar (PR) showed that powerful storms in Vongfong's eye wall were producing very heavy rainfall. TRMM's Microwave Imager (TMI) show that multiple rain bands spiraling into Vongfong were also dropping rain over a large area.
On Oct. 8 at 02:15 UTC (Oct. 7 at 10:15 p.m. EDT), the MODIS instrument aboard NASA's Terra satellite captured a visible image of Super Typhoon Vongfong's wide cloud extend and the storm's wide circular eye.
On Oct. 8 at 1500 UTC (11 a.m. EDT), Vongfong had maximum sustained winds near 145 knots (167 mph/268.5 kph) making it a Category 5 Super Typhoon on the Saffir-Simpson Scale. It was centered near 18.7 north and 130.7 east.
It was centered about 510 nautical miles (586 miles/944.5 kph) south-southeast of Kadena Air Base, Okinawa, Japan. Vongfong was moving to the north at 7 knots (8 mph/13 kph). It was creating extremely rough seas in the Philippine Sea, with wave heights to 50 feet (15.2 meters).
According to the U.S. Kadena Airbase, on Oct. 8, a combined Japanese-U.S. Air Force rescue team recovered the body of the third Airman who had been swept out to sea on Oct. 5 from Typhoon Phanfone.
The Joint Typhoon Warning Center predicts that Vongfong is predicted to weaken slightly while moving toward the islands of southern Japan.
Rob Gutro/Hal Pierce
NASA's Goddard Space Flight Center
Rob Gutro | Eurek Alert!
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering | <urn:uuid:e116ca19-a5d6-47b3-b010-755f6bd0cbd7> | 3.21875 | 1,183 | Content Listing | Science & Tech. | 56.22537 | 95,531,556 |
Physicist Art Hobson has offered a solution, within the framework of standard quantum physics, to the long-running debate about the nature of quantum measurement.
In an article published August 8 by Physical Review A, a journal of the American Physical Society, Hobson argues that the phenomenon known as “nonlocality” is key to understanding the measurement problem illustrated by “Schrodinger’s cat.”
In 1935, Nobel Laureate Erwin Schrodinger used the example of a cat in a closed box to illustrate the central paradox of quantum physics: microscopic particles such as electrons, photons or atoms can exist in two quantum states at once. These states are known as “superpositions.”
“A measurement in quantum physics means using some sort of large-scale macroscopic device, such as a Geiger counter, to learn something about the quantum state of a microscopic system, such as an atom or a single photon,” Hobson said. “Quantum theory seems to imply that if you connect the microscopic system to a large-scale measuring device that distinguishes between the two distinct states of the microscopic system, then the Geiger counter will be also ‘entangled’ into a superposition of existing in two simultaneous states. However, this is something that we never observe and is not acceptable.”
Using Schrodinger’s illustration, Hobson said the cat plays the role of the Geiger counter that is connected to a radioactive nucleus in order to determine the decayed or undecayed state of the nucleus. A “live cat” would be a macroscopic signal of an undecayed nucleus and a “dead cat” would be the macroscopic signal of a decayed nucleus. Quantum theory seems to say that the cat should therefore be entangled into a superposition of being both dead and alive, he said.
Instead, Hobson writes in his article that the cat’s quantum state is “entangled” with the atom’s state, implying that there is an important “nonlocal relation,” or instantaneous action-at-a-distance, between the two. According to nonlocality, if any two entangled objects are sent in opposite directions and the state of one of them is altered, the second instantly alters its state in response no matter how far apart the two may be. Hobson cites direct experimental evidence supporting his analysis, from experiments performed in 1990 involving nonlocal observation of entangled pairs of photons.
“The strange thing is that the action happens instantly, with no time for light or an electromagnetic signal or radio signal to communicate between the two,” Hobson said. “It is a single object that is behaving as a single object but it is in two different places. It doesn’t matter what the distance is between them.
That phenomenon must be taken into account to resolve the measurement problem, he said. That means with Schrodinger’s cat, the cat is no longer predicted to be both dead and alive. It is instead dead if the nucleus decays, and alive if the nucleus does not decay, just as one would expect.
According to Hobson, since 1978, three previous published analyses have suggested similar solutions to the measurement problem, but the earlier solutions were little noticed at the time and the debate continued, “leading to confusion and even to pseudoscientific claims about the implications of quantum physics,” he said.
“It’s important to sort out the foundations of quantum physics,” Hobson said. “This theory is more than a century old now, and these ideas have been out there but they haven’t been noticed or taken seriously enough. It is my hope that this resolution of the measurement problem will now be accepted by the quantum foundations community.”
Contact:Art Hobson, professor emeritus, physics
Chris Branam | Newswise
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
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18.07.2018 | Life Sciences
18.07.2018 | Health and Medicine | <urn:uuid:c4e1b4b3-3d4c-4cec-9d74-636f0df347e3> | 3.5 | 1,455 | Content Listing | Science & Tech. | 39.594996 | 95,531,570 |
Flex is a programming language developed on adobe technology
to enhance the users capability in building rich internet applications. This
latest adobe technology possesses all flash features. Flex is embedded with two
languages MXML and Action Script respectively. Among all known scripting
languages Action Script is one of them that comes along with Flex SDK(software
development kit). MXML is a tag based language while Action Script is a flash
language and developers pro to oop's (object oriented programming) will face no
problem with this flash language.
Server the compilation of flex source file is adobe's Application server which is a J2EE application.
Flex coding is done with an XML based language known as MXML and like Flash applications, Flex codes too are compiled into a file having SWF format called ShockWave Flash files. These SWF files are executed with stand-alone Adobe's Flash Players, and can also be directly executed in browsers that have Adobe Flash Player Plug-in installed.
For developing Flex applications, Adobe has launched Flex builder that works in Eclipse environment. Flex 3 builder is the latest and can be freely downloaded from Adobe's official website. But building Flex applications on Flex builder in eclipse environment is a cumbersome job to perform, one reason is that using eclipse with flex builder plugin will make it very slow, also lot of time is been taken in compilation. To get rid of this problem there is another way to compile Flex application which works on Apache Ant technology. Apache's this technology is used to make a build.xml file that will be used later to call the flex compiler in deploying the flex application. You will get more to know after going through the tutorials presented below.
Flex coding involves two different languages MXML and ActionScript respectively.
MXML is an extended form of XMLand is a tag based language, and therefore it is called an XML-based markup language. Program files coded with mxml language possess '.mxml' extensions. MXML used along with ActionScript provide tags to devise GUI (graphical user interface) component and is also used to get access to data on servers. MXML facilitates its users with its data binding services. HTML and MXML both provide tags but the difference is that MXML consists of several new tags like TabNavigators and Accordions and many more that also enable users to get any web service connection. A MXML file is converted into a SWF file that runs on a Flash Player or on a browser which has Adobe Flash Player Plug-in installed in it. | <urn:uuid:cc9db9b6-cc77-40b8-bd48-b77c26969e09> | 2.96875 | 517 | Knowledge Article | Software Dev. | 44.420652 | 95,531,577 |
All the planets of the Solar system revolve around the Sun in a common plane and are oriented relative to themselves it almost the same. Only Uranus stands out in this series, rotating almost on its side: its axis declined by as much as 98 degrees.
Hard to believe that it happened “by itself”, and astronomers have long been suggesting that this situation is an ice giant came after one or several collisions with other large bodies.
The details of that distant catastrophe opened the computer simulation conducted recently by Jacob Kegerreis (Jacob Kegerreis) from the British Durham University and his colleagues. The supercomputer has allowed details to shortchange more than 50 scripts for impact and to consider options leading to the desired result — the same orientation and speed as that of the present Uranium. This researchers write in an article published in The Astrophysical Journal.
The work confirmed previous calculations about the size of the mystical body: apparently, it was exceptionally large — at least twice heavier than Earth. The collision occurred about four billion years ago, in the young Solar system. The main blow fell on a tangent and changed the rotation of Uranus, but allowed him to retain at least 90 percent of its atmosphere.
He left other traces — for example, in the form of rings and the many satellites of the giant planets. Their plane of rotation is also tilted relative to the plane of the Solar system because they formed from the material trapped in orbit after the collision.
Distant, “irregular” moons of Uranus, showing other variants of the orbits, could be captured after the event. In addition, such a blow could transfer a lot of energy into the bowels of the planet, creating in them the melted sections of ice and rock.
This, in turn, can explain the specific features of the magnetosphere of Uranus: it is strongly deflected from the axis of rotation that is offset from its geometric center by about one-third of the radius of the planet and generally asymmetrical.
This anomaly could also occur long after the collision. | <urn:uuid:121c0888-f9bb-4e67-8ab5-5d88b9e19476> | 3.890625 | 423 | News Article | Science & Tech. | 36.209414 | 95,531,581 |
Species Detail - Manx Shearwater (Puffinus puffinus) - Species information displayed is based on all datasets.
Terrestrial Map - 10kmDistribution of the number of records recorded within each 10km grid square (ITM).
Marine Map - 50kmDistribution of the number of records recorded within each 50km grid square (WGS84).
Protected Species: Wildlife Acts || Threatened Species: Birds of Conservation Concern || Threatened Species: Birds of Conservation Concern >> Birds of Conservation Concern - Amber List
1 January (recorded in 2000)
31 December (recorded in 2012)
National Biodiversity Data Centre, Ireland, Manx Shearwater (Puffinus puffinus), accessed 21 July 2018, <https://maps.biodiversityireland.ie/Species/10030> | <urn:uuid:5b0b48bf-3005-4571-8afe-c1f28ea64d42> | 2.75 | 172 | Structured Data | Science & Tech. | 27.255263 | 95,531,593 |
MLZ is a cooperation between:> Technische Universität München> Helmholtz-Zentrum Geesthacht> Forschungszentrum Jülich
Dr. Jitae Park at the thermal three axes spectrometer PUMA. © Volker Lannert / DAAD
Transporting electricity without losses is the promise of superconducting materials. Two research teams have studied the new class of iron-based superconductors at the instrument PUMA the Heinz Maier-Leibnitz centre and independently came to the same surprising result: The superconducting Cooper pairs change their symmetry.
Iron-based superconductors are a complete mystery for researchers: As iron is actually a magnetic material, which should prevent the superconductivity. Considering the electrons as tiny compass needles, all are in parallel in the magnetized iron. However, for conventional superconductivity, the electrons must be coupled antiparallel with spherical symmetry (phase preserved order) for the formation of the superconducting Cooper pairs. This seems to be different with iron-based superconductors. Therefore, they are also named “unconventional superconductors”.
Scattered neutrons off from an unconventional superconductor often carry the information about the structure of the superconducting electron pair (Cooper pair). Here, researchers always observed in the iron-containing superconductors a peculiar excitation of spins briefly below the transition temperature at which the material becomes superconducting. This so-called magnetic resonant mode indicates a phase reversed alignment of the electron compass needles, supporting that the spin excitations are a sort of “glue” for the Cooper pairs.
With the collaboration of TUM scientist Dr. Jitae Park on three-axes spectrometer PUMA, however, the two scientific teams from Japan and China led by Dr. Chul-ho Lee at Advanced Industrial Science and Technology and Porf. Jun Zhao at Fudan University observed a transition from phase-reversed to phase-preserved Cooper pair formation. This reversal of the signs obviously depends on the degree of doping of the iron-selenide and iron-arsenide superconductors under investigation: If the superconductor had more than 50% sulfur in the iron-selenides and 80% of potassium in the iron-arsenides added, the mode suddenly disappears, indicating that the electron pairs changed back to phase-preserved symmetry.
“Our findings suggest that the iron-based superconductors are much more complicated than previously thought,” says TUM scientist Jitae Park. Further measurements with neutrons are therefore already planned.
Suppression of spin-exciton state in hole overdoped iron-based superconductors
C. H. Lee, K. Kihou, J.T. Park, K. Horigane, K. Fujita, F. Waßer, N. Qureshi, Y.Sidis, J.Akimitsu, M. Braden
Scientific Reports 6, Article number: 23424 (2016), DOI: 10.1038/srep23424
Transition from Sign-reversed to Sign-preserved Cooper-pairing Symmetry in Sulfur-doped Iron Selenide Superconductors
Qisi Wang, J. T. Park, Yu Feng, Yao Shen, Yiqing Hao, Bingying Pan, J. W. Lynn, A. Ivanov, Songxue Chi, M. Matsuda, Huibo Cao, R. J. Birgeneau, D. V. Efremov, and Jun Zhao
Phys. Rev. Lett. 116, 197004 | <urn:uuid:957e6dee-df65-47b8-ba79-a6d6555de933> | 3.046875 | 774 | News (Org.) | Science & Tech. | 35.454593 | 95,531,594 |
Cutting-edge technology and science of the NSF-funded WISSARD project make discovery possible
B-roll from the WISSARD project is available by contacting Dena Headlee, firstname.lastname@example.org / (703) 292-7739.
In a finding that has implications for life in other extreme environments, both on Earth and elsewhere in the solar system, researchers funded by the National Science Foundation (NSF) this week published a paper confirming that the waters and sediments of a lake that lies 800 meters (2,600 feet) beneath the surface of the West Antarctic ice sheet support "viable microbial ecosystems."
Given that more than 400 subglacial lakes and numerous rivers and streams are thought to exist beneath the Antarctic ice sheet, such ecosystems may be widespread and may influence the chemical and biological composition of the Southern Ocean, the vast and biologically productive sea that encircles the continent.
According to Brent C. Christner, the paper's lead author and a researcher with the NSF-funded Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project, "Hidden beneath a half-mile of ice in Antarctica is an unexplored part of our biosphere. WISSARD has provided a glimpse of the nature of microbial life that may lurk under more than 5 million square miles of ice sheet."
Analysis of the samples taken from subglacial Lake Whillans, the researchers indicate, show that the water contains a diverse microbial community, many members of which can mine rocks for energy and use carbon dioxide as their source of carbon.
Added John Priscu, a WISSARD scientist at Montana State University, Bozeman and a co-author on the paper, the Antarctic subglacial environment is our planet's largest wetland, one dominated completely by microorganisms.
The WISSARD findings are published in the Aug. 21 issue of the journal Nature by scientists and students affiliated with WISSARD, which is a collaboration involving researchers at numerous institutions across the United States.
Christner is a professor of biology at Louisiana State University (LSU). Other co-authors on the paper include students and researchers from LSU; the University of Venice in Italy; New York University; the Scripps Institution of Oceanography; St. Olaf College in Minnesota; the University of Tennessee; and Aberystwyth University in the United Kingdom.
NSF, which manages the U.S. Antarctic Program through its Division of Polar Programs, provided more than $10 million in grants as part of NSF's American Recovery and Reinvestment Act of 2009 portfolio to support the WISSARD science and development of related technologies.
NASA's Cryospheric Sciences Program, the National Oceanic and Atmospheric Administration and the private Gordon and Betty Moore Foundation also provided support for the project.
The WISSARD team made scientific and engineering history in late January of 2013 when they used clean hot-water drilling technology to access subglacial Lake Whillans. This permitted the retrieval of pristine water and sediment samples that had been isolated from direct contact with the atmosphere for many thousands of years.
The interdisciplinary WISSARD research team included groups of experts in the following areas of science: life in icy environments, led by Priscu; glacial geology, led by Ross Powell, of Northern Illinois University; and glacial hydrology, led by Slawek Tulaczyk, of the University of California, Santa Cruz.
Definitive evidence of life in subglacial lakes
The realization that a vast aquatic system of rivers and lakes exists beneath the ice in Antarctica has spurred investigations to examine the effect on ice-sheet stability and the habitability of environments at the bed. The latest WISSARD announcement is the first to provide definitive evidence that a functional microbial ecosystem exists beneath the Antarctic ice sheet, confirming more than a decade of speculation about life in this environment.
Using various methods, including airborne radar surveys, scientists have built a knowledge base about Antarctica's subglacial hydrological system over the past 40 years. The largest of the subglacial lakes, subglacial Lake Vostok in East Antarctica, is one of the largest lakes on our planet in terms of volume and depth and has been isolated beneath the ice sheet for more than 10 million years.
Samples of microbes from Lake Vostok have been collected indirectly by examining ice collected above the liquid part of the Lake- ice that refroze--accreted--on the bottom of the ice sheet.
These samples, which were described in 1999 by Priscu, the chief scientist of the WISSARD project, and David Karl of the University of Hawaii, presented the first evidence for life beneath the huge Antarctic ice sheet.
However, the drilling techniques used to retrieve the Vostok samples and the low amount of microbial biomass present in the samples had called into question previous studies that concluded the lake supports a living ecosystem.
The WISSARD team drilled into subglacial Lake Whillans using a clean hot-water drill and incorporated rigorous measures to avoid the introduction of foreign material into the lake.
The approach to drilling was guided by recommendations in the 2007 National Research Council-sponsored report, "Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship," aimed to protect these unique environments from contamination.
A team of engineers and technicians directed by Frank Rack of the University of Nebraska-Lincoln, designed and fabricated the specialized hot-water drill that was fitted with a filtration and germicidal UV system to prevent contamination of the subglacial environment and to recover clean samples for microbial analyses. In addition, the numerous customized scientific samplers and instruments used for this project were also carefully cleaned before being lowered into the borehole through the ice and into the lake.
A major concern that drove the clean-drilling techniques and protocols is that it is still unclear how interconnected the subglacial aquatic system is. Researchers did not want to risk contaminating the entire system through their sampling of one body of water.
The newly published paper also raises a separate issue of the connectivity of Lake Whillans to the wider global ecosystem, noting that the lake is part of network of three major reservoirs beneath the Whillans Ice Stream that regulate the transportation of water to a subglacial estuary--an area where fresh and salt water mix--which links the subglacial aquatic system to the ocean beneath the Ross Ice Shelf.
"Given the prevalence of subglacial water in Antarctica," the researchers write, "our data...lead us to contend that aquatic microbial systems are common features of the subsurface environment that exists beneath the ... Antarctic ice sheet."
Peter West, NSF, (703) 292-7530, email@example.com
Dawn Jenkins, Louisiana State University, (225) 578-2935, firstname.lastname@example.org
Evelyn Boswell, Montana State University, (406) 994-5135, email@example.com
Whitney Heins, University of Tennessee, Knoxville, (865) 974-5460, firstname.lastname@example.org
James Devitt, New York University, (212) 998-6808, email@example.com
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2014, its budget is $7.2 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly.
Peter West | Eurek Alert!
Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center
NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences | <urn:uuid:b77114c9-a2c2-4f70-8702-e9358aec81f1> | 3 | 2,196 | Content Listing | Science & Tech. | 33.472657 | 95,531,615 |
News & Blogs
Polar Vortex Hype Has Returned With Arctic Blast on the Way
Published: December 13, 2016
The term "polar vortex" wasn't born during the winter of 2014, but that's certainly when it became an internet star.
For the last three winters, virtually every forecast that brought cold weather into the United States was met with one question: "Is this the polar vortex?" Now, as the North prepares for multiple rounds of frigid weather, the polar vortex is back in the news.
It's true that the upcoming round of cold weather is associated with the polar vortex, but it's important to note what this phenomenon is, as well as what it isn't.
What It Is: An Upper-Atmospheric Area of Low Pressure
Our weather takes place in the atmospheric layer known as the troposphere, stretching anywhere from 4 to 12 miles above the ground. One layer above that is the stratosphere, which is where the polar vortex mostly resides.
There are actually two polar vortices – one each at, or around, the North and South Poles. In the respective hemisphere's colder months, increased temperature differences between the mid-latitudes and the poles create a stronger vortex.
But if you're a cold-weather lover, a strong polar vortex actually keeps colder air locked in closer to the pole. In order for the arctic air to surge southward and into the U.S. or Europe, the stratosphere must warm, weakening and elongating the polar vortex.
As weather.com meteorologists Jon Erdman and Linda Lam wrote in a previous article on this topic, if you want the colder air to stay away, root for a strong polar vortex.
What It Is Not: Any Kind of Storm, Nor a Storm System
Just because your area is getting hit by a potent winter storm does not mean that the storm itself is the "polar vortex." This phenomenon is a permanent feature of our atmosphere; it doesn't quite behave like a storm system.
In other words, the polar vortex might play some role in helping to push extremely cold air southward in the coming days, but it won't be responsible for spawning a nasty winter storm. Remember, the polar vortex isn't found in the layer of the atmosphere where weather occurs, so while the different layers interact, storm systems aren't formed in the stratosphere.
Additionally, as mentioned earlier, the polar vortex isn't a newcomer to meteorology. This is a phenomenon that scientists have known about since before the Civil War, according to Stu Ostro, senior meteorologist at The Weather Channel.
"Global warming did not create polar vortexes, though the changing climate might be changing the nature of them," Ostro wrote in early 2014. "Nor did humans create the term this week ... it's been an accepted scientific one for at least 75 years."
MORE: Winter Storm Caly
The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM. | <urn:uuid:db5e5c0d-bdda-438d-9f9f-0fa3f667950a> | 2.6875 | 640 | News Article | Science & Tech. | 53.007681 | 95,531,616 |
A few days ago I read an article I saw on Twitter discussing how analysing the time it takes your application to do stuff can lead to the discovery of security flaws. The actual flaw seems rather obvious once explained, too obvious infact, so I decided to test it out in Ruby. My results are documented below.
So whats the flaw?
One of the important rules of security is to never let anyone know more than they need to about your system. The article focuses on the use of hashes which are used for authentication, called HMACs. These are typically generated in order to sign requests in order to verify their authenticity and integrity.
Hashes are a predefined length, SHA-1 for example returns hashes of 160 bits, or 20 bytes. The human-friendly hexadecimal notation is commonly used for hash representation. Each byte is converted into a hexadecimal nibble (two characters) which returns a string of 40 characters. Rather than converting hashes back into binary format, comparison methods typically compare them character by character.
def are_equal?(str1, str2) # not valid if lengths are different return false unless str1.length == str2.length # check each character str1.each_index |i| return false unless str1[i] == str2[i] end # yay true end
For a hash of, say, 20 bytes (SHA1), this will take less than 200μs on modern computers. The flaw is that the execution time varies depending on how many characters match. Let’s say the initial length check (line 3) takes 10μs, and then each comparison (line 7) takes 5μs. For matching hashes the function will take 110μs to execute, however for hashes where only the first 5 characters match it will take 35μs to execute. Now we have the information.
Meh, so what?
Information is power, or so they say. In this case it is a security breach. By generating a group of hashes where the first byte is 0 – 255, one of them will take slightly longer to execute. By taking a large number of samples, it is possible to reliably use this method to work out what the value of the byte is. This can then be done for the rest of the bytes in the hash. After this you are in.
In my experimentation with this in Ruby I found that taking 500 samples, and then taking the median execution time for each sample gave accurate results. According to the original article it is even possible to reliably do this over the internet, assuming the number of samples is high enough. I am not entirely convinced by this however, as the latency produced by the internet can vary wildly by hundreds of milliseconds for each request. I don’t see how it is possibly to tell a difference of a few microseconds in this case.
$ ping www.google.com PING www.l.google.com (22.214.171.124): 56 data bytes 64 bytes from 126.96.36.199: icmp_seq=0 ttl=53 time=275.568 ms 64 bytes from 188.8.131.52: icmp_seq=2 ttl=53 time=177.634 ms 64 bytes from 184.108.40.206: icmp_seq=3 ttl=53 time=270.396 ms 64 bytes from 220.127.116.11: icmp_seq=4 ttl=53 time=343.046 ms 64 bytes from 18.104.22.168: icmp_seq=5 ttl=53 time=206.094 ms 64 bytes from 22.214.171.124: icmp_seq=6 ttl=53 time=275.967 ms 64 bytes from 126.96.36.199: icmp_seq=7 ttl=53 time=348.216 ms 64 bytes from 188.8.131.52: icmp_seq=8 ttl=53 time=226.734 ms 64 bytes from 184.108.40.206: icmp_seq=9 ttl=53 time=288.783 ms 64 bytes from 220.127.116.11: icmp_seq=10 ttl=53 time=342.466 ms ^C --- www.l.google.com ping statistics --- 10 packets transmitted, 10 packets received, 0% packet loss round-trip min/avg/max/stddev = 177.634/275.490/348.216/55.956 ms
Back to Ruby
Fortunately, Ruby does things differently. The string comparison method in Ruby is not time dependent. I decided to look in the source after I only got successful results when implementing the comparison method above. In Ruby the lexicographical string comparison method is called (str1 <==> str2, which returns an integer), and then this is checked to see whether it is 0, and the strings match. An example of this is shown below:
def are_equal?(str1, str2) # not valid if lengths are different return false unless str1.length == str2.length # check each character result = 0 str1.each_index |i| result |= str1[i] ^ str2[i] end # check equal return result == 0 end
This sets a flag in result whenever the characters don’t match, and at the end this is checked to ensure no flags have been set and the strings match.
So if you ever need to implement your own comparison function (why I don’t know), make sure that you aren’t revealing information that can lead to a security flaw. If you use a prebuilt on make sure it is up to scratch.
Bed time now I think as it is 3:41am. Drinking a can of Relentless isn’t a good idea before going to bed. | <urn:uuid:544e7d68-50c4-41b5-94bf-80c07f4cda7b> | 2.609375 | 1,236 | Personal Blog | Software Dev. | 85.106558 | 95,531,626 |
The electron transport chain is comprised of a series of enzymatic reactions within the inner membrane of the mitochondria, which are cell organelles that release and store energy for all physiological needs.
As electrons are passed through the chain by a series of oxidation-reduction reactions, energy is released, creating a gradient of hydrogen ions, or protons, across the membrane. The proton gradient provides energy to make ATP, which is used in oxidative phosphorylation.
Schematic representation of the electron transfer chain via chemiosmotic reactions. Image Credit: Ellepigrafica / Shutterstock
The reactions of the electron transport chain are carried out by a series of membrane proteins and organic molecules. They are arranged in four complexes. In eukaryotes, the electron transport chain is located in the inner mitochondrial membrane. In prokaryotes, it is located within the plasma membrane.
Electrons move through the electron transport chain from a higher to lower energy state. Energy release moves protons through channels in the membrane proteins, moving them into the inner membrane space. This leads to a buildup of positively charged protons, which creates an electrical potential across the membrane.
The reactions of the electron transport chain involve several large membrane protein complexes within the inner mitochondrial membrane. Some are described below.
The NADH Dehydrogenase Complex
The NADH dehydrogenase complex (Complex I) contains more than 40 polypeptides. It transfers electrons from NADH to coenzyme Q10. The reaction begins when NADH binds to Complex I, transferring two electrons to the flavin mononucleotide (FMN) prosthetic group, resulting in the formation of FMNH2. The electrons are then transferred through iron-sulfur clusters to coenzyme Q10. The change in redox state of the protein induces a conformational change, causing the four hydrogen ions to be pumped into the inner membrane space. Four protons are thus transported across the membrane in the reaction.
Succinate Dehydrogenase (Complex II)
Succinate dehydrogenase, also known as succinate-CoQ reductase, receives electrons into the quinone pool from succinate and transfers them to to Q. Complex II has four subunits. Complex II operates parallel to Complex I. However, no protons are transported into the intermembrane space. This enzyme also takes part in the tricarboxylic acid (citric acid) cycle as well.
The Cytochrome b-c1 Complex
The cytochrome b-c1 complex (Complex III), has 11 polypeptide chains and functions as a dimer, and is also known as coenzyme Q: cytochrome c-oxidoreductase or cytochrome c reductase. Three heme groups are found within each monomer, bound to cytochromes and an iron-sulfur protein. The function of the b-c1 complex is via a Q-cycle mechanism. It catalyzes the reduction of cytochrome c by the oxidation of coenzyme Q while pumping 4 protons from the mitochondrial matrix to the intermembrane space. Mutations of Complex III are associated with exercise intolerance and some multisystem disorders.
Cytochrome c Oxidase
Cytochrome c oxidase is the last step in the electron transport chain. It functions as s dimer, with each monomer containing 13 different polypeptide chains, including two cytochromes and two copper atoms. It accepts two electrons from two cytochrome c molecules and passes them four at a time to oxygen. Mutations of cytochrome c oxidase can lead to severe metabolic disorders. The cytochrome oxidase reaction uses about 90 percent of the oxygen taken up by most cells.
Cytochrome c oxidase, subunit Vb, a subunit of mitochondrial cytochrome c oxidase complex, an oligomeric enzymatic complex which is a component of the respiratory chain complex. 3d rendering. Image Credit: ibreakstock / Shutterstock Uncoupling
Electron transport can be uncoupled from ATP synthesis through the use of certain agents or some natural processes. Some specialized fat cells, known as brown fat, uncouple the electron transport chain in order to dissipate the energy as heat. This is accomplished through a transport protein that moves protons down the electrochemical gradient, bypassing ATP synthase. The cells oxidize their fat stores rapidly, producing heat. Hibernating animals and newborn human babies have brown fat.
Reviewed by Liji Thomas, MD. | <urn:uuid:9d3e944b-ca9c-48bb-b7b1-93941ea99148> | 3.625 | 954 | Knowledge Article | Science & Tech. | 28.358801 | 95,531,647 |
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Edited By: C Cockell and AR Blaustein
221 pages, Figs, tabs
Much has been written about the effects of increased UV radiation caused by stratospheric ozone depletion on the weather, but there has been a dearth of publications on the role of UV on ecosystems as a whole. Now that much more is known about the effects of UV radiation at the organism level, we are gaining an understanding of how this impacts on specific ecosystems. From microbial to plant ecosystems, the book examines how changes in UV radiation, caused by anthropogenic ozone depletion, as well as changes in radiation levels throughout the evolution of life on Earth, can alter species composition and interspecies competitiveness. Two foci of the book are the evolutionary aspects of the effects of UV and also the various synergistic interactions of UV radiation with other environmental factors. Because our knowledge of UV effects on whole ecosystems is still at a relatively early stage, an important part of each chapter is an overview of future research directions and indications of where new data and knowledge are needed.
1. Introduction - From Molecules to Ecosystems (C. COCKELL & A. BLAUSTEIN) * 2. Changes in the Physical Environment (S. MADRONITCH, M. BLUMTHALER, A. WEBB) * 3. UV Radiation and Evolution (C. COCKELL & F. GARCIA-PICHEL) * 4. UV Radiation and Aquatic Microbial Ecosystems (D. HADER) * 5. UV Radiation and Terrestrial Microbial Ecosystems (W. VINCENT) * 6. UV Radiation and Plant Ecosystems (M. CALDWELL) * 7. UV Radiation and Amphibians (A. BLAUSTEIN) * 8. UV Radiation and Coral Communities (A. SHICK & B. GREGORY) * 9. UV Radiation and Fish (T. SIEBECK) * 10. Artificial Ecosystems (C. COCKELL, M. TEVINI, M. CALDWELL) * Index.
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Recently there was some research done on Alzheimer’s disease using a game that collated data from a vast number of people. It was revealed that if the research had been done in a clinical, controlled trial it would have taken over 2000 years to collect the same amount of data. This is one of the best and most informative study’s ever done using citizen science, where “regular people” (non-scientists) collect the data and are actively involved.
Unsurprisingly this led to a lot of hype and lots of people calling for more citizen science. All very admirable we can agree but it is not without its problems.
Citizen science is not easy. The Alzheimer study was so good because it had been set it up with citizen science in mind and designed specifically for this purpose. This is a very important point and it led to vast numbers of people being able to do something relatively simple to help. The medical world seems to have a better grasp on this than the world of conservation where citizen science is often dismissed for being poor quality and some key journals are allegedly refusing to publish papers based on citizen science derived data. Some think this is academic snobbery whereas others argue that often the projects are poorly run leading to errors which then cannot be published.
I follow a lot of marine science quite closely and regularly see citizen science crop up in one guise or another. Likely this is due to a lack of funding in this area which means researchers cannot afford full scale studies and must adapt. This is fine, but not all projects are being carried out in a useful way because the experimenters are not designing the project in the knowledge that it will be “normal” people who are doing the data collection. In some cases researchers are only offering advice to groups and then the groups do everything themselves, including publishing the results. The results are not published academically but are made publicly available and are then leading to people having incorrect ideas on the health of marine systems, particularly when the results make local or national news before anyone checks the facts. The purpose of academic publications is to have everything peer reviewed before publication to ensure that the details are correct, to skip this step really calls into question how scientific the project is and how much trust can be placed in its findings.
Marine and coastal science is often an exceedingly difficult area to get data from, seabird surveys for example are 70% accurate at best, sometimes as low as 30% and this leads to a huge issues with data analysis. Many people on this website are students and recent graduates who are all too familiar with statistical analysis and are aware of the degree of confidence required in your results prior to publication.
If you are unfamiliar then try this example. You count 5000 animals in 2015, alter conditions and count 5500 animals in 2016. The population has gone up by 500 and proves whatever you have changed has worked, right?
As you may have guessed that is not necessarily the case. To make that claim you would need to prove that the change wasn’t due to different people counting, different weather, time of year, and a vast, vast, number of other factors. In the case of seabirds if the very best studies are only counting 7 out of every 10 birds then there is clearly huge scope for error, error that needs to be statistically controlled for. But that is only to prove the population change, to prove that what you did caused the population change is a huge leap requiring compelling evidence. This level of analysis needs to be done in all research and yet it is missing in a great deal of citizen science. By no means is that the fault of the citizens, rather the motivation of the researcher(s) or the design of the project is the issue.
The purpose of this is not to shame the groups involved. It is unlikely that anyone is deliberately setting out to mislead, although there have been rare occasions when citizen science projects were created to “prove” certain things in order to influence decisions (a claim that can be levelled at academic research as well) . Some of the time it seems the projects are either without academic support at all or are not a priority for researchers which undermines the amount of work being put it.
Citizen science is not the problem, the problem is that it needs to be recognised as real research and treated as such. Researchers need to commit to their groups, provide any necessary training and design the experiment in such a way as to minimise data collection errors. This is not necessarily more difficult or easier than a fully academic project but it does require a different approach. If citizen science is going to make the same sort of positive contribution to conservation that it can make in other fields then it must be an all or nothing situation where it is done properly or not at all. Given that people are clearly willing to help then designing a project that takes advantage of this is surely the way forward.
There is a good summary of the issues, particularly in the comments section, in the Nature link below.
As always, let me know what you think in the comments below.
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NASA's Prototype Lunar Greenhouse For Mars And Moon
NASA's researchers are working hard to develop an inflatable greenhouse, called the Prototype Lunar Greenhouse, for crops as well as air revitalization and water recycling.
(NASA's inflatable greenhouse)
The prototype involves an inflatable, deployable greenhouse to support plant and crop production for nutrition, air revitalization, water recycling and waste recycling. The process is called a bioregenerative life support system...
NASA scientists and engineers are developing systems to harness resources such as water that should be available in certain areas of the lunar or Martian surface to support missions lasting for months or years.
"We're mimicking what the plants would have if they were on Earth and make use of these processes for life support," said Dr. Gene Giacomelli, director of the Controlled Environment Agriculture Center at the University of Arizona. "The entire system of the lunar greenhouse does represent, in a small way, the biological systems that are here on Earth."
A professor in the University of Arizona's Agricultural and Biosystems Engineering Department, Giacomelli explains the next big step is to use additional lunar greenhouse units for specialized testing to ensure the system being developed will adequately support a crew of astronauts working on the moon or Mars.
"We will develop computer models to simulate what we're doing to automatically control the environment and provide a constant level of oxygen," he said.
Once a good idea, always a good idea. In his 1951 story Asteroid of Fear, Raymond Z. Gallun describes in detail an inflatable garden for space:
Now he started unrolling great bolts of a transparent, wire-strengthened plastic. Patching with an adhesive where explosion-rents had to be repaired, he cut hundred-yard strips, and, with Rose's help, laid them edge to edge and fastened them together to make a continuous sheet. Next, all around its perimeter, he dug a shallow trench. The edges of the plastic were then attached to massive metal rails, which he buried in the trench.
"Sealed to the ground along all the sides, Honey," he growled to Rose. "Next we fit in the airlock cabinet, at one corner. Then we've got to see if we can get up enough air to inflate the whole business. That's the tough part—the way things are...."
After the massive airlock was in place, they attached their electrolysis apparatus to the small atomic battery, which had been used to run the well-driller. The well was in the area covered by the sheet of plastic, which was now propped up here and there with long pieces of board from the great box. Over their heads, the tough, clear material sagged like a tent-roof which has not yet been run up all the way on its poles.
Technovelgy readers also recall the martian saw grass from engineer/sf writer George O. Smith's 1942 classic QRM - Interplanetary, which uses the idea of plant revitalization of air for astronauts.
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Enhancing Protected Area Mangement and supporting climate change adaptation of climatically vulnerable ecosystems of India
As of: July 2018
Objective and activities
A study funded by BMU provided data to identify some of the most critical issues and sites for enhanced climate change adaptation, where it was apparent that climate impacts rendered communities and ecosystems more vulnerable unless certain practices are modified. However, more detailed studies are needed to further refine strategies, and to identify and prioritise additional vulnerable areas and communities. A feasibility study and a preliminary climate vulnerability assessment were therefore financed, as well as a first implementation of pilots on a minor scale in already identified sectors and regions. Based on the results of the study, planned interventions can be adjusted and further proposals for adequate investment measures were formulated.
State of implementation/results
- Project completed
- Study with three components compiled: Vulnerability analysis of population and ecosystems; derivation of possible investment measures; derivation of pilot measures
- Study results made an important contribution to the preparation of a climate adaptation programme (GIZ and KfW) in the same region, financed by the German Federal Ministry for Economic Cooperation and Development (BMZ); information is available to the governments of the two states Sikkim and Arunachal Pradesh in north-eastern India in the development of adaptation strategies to climate change. | <urn:uuid:9869eed4-d188-4134-8035-2d8afe09ee9d> | 2.671875 | 270 | Knowledge Article | Science & Tech. | -27.295973 | 95,531,712 |
Scientists said Monday they had discovered fragments of the meteor that spectacularly plunged over Russia’s Ural Mountains creating a shockwave that injured 1,200 people and damaged thousands of homes.
The giant piece of space rock streaked over the city of Chelyabinsk in central Russia on Friday with the force of 30 of the nuclear bombs dropped on the Japanese city of Hiroshima during World War II.
It exploded a few dozen miles (kilometres) above Earth but its pieces were widely believed to have scattered over large swathes of the industrial region.
Recovery workers scouring a small lake where at least some of the fragments were believed to have fallen were unable to discover anything in their initial search.
But members of the Russian Academy of Sciences that conducted chemical tests on some unusual rocks on Sunday said the pieces had come from outer space.
“We confirm that the particles of a substance found by our expedition near Lake Chebarkul really do have the composition of a meteorite,” RIA Novsosti quoted Russian Academy of Sciences member Viktor Grokhovsky as saying late Sunday.
Grokhovsky’s Urals Federal University separately posted a statement on its website on Monday that featured a photograph of a person holding a tiny piece of porous black rock between his index finger and thumb.
“This meteorite belongs to the class of regular chondrites,” the university statement said.
Grokhovsky said the rock in question was composed in part of metallic iron as well as chrysolite and sulfite.
Its iron content was estimated at 10 percent.
“Most likely, (the find) will be called Meteorite Chebarkul,” the Russian university said.
The meteor’s shockwave blew out the windows of nearly 5,000 buildings and left 40 people — including three children — recovering in hospital Sunday with cuts and more serious injuries.
About 24,000 emergency workers and volunteers were busy replacing smashed windows over the weekend in time for the resumption of school and work.
But the elusive meteorites — meteor fragments that have hit Earth — have generated interest as well.
Russian space debris hunters have posted ads on websites offering as much as 300,000 rubles ($10,000) for an authentic piece of the latest space rock to hit the planet.
Chelyabinsk authorities responded by cordoning off the area around the lake and not allowing any media or independent researchers hunting for meteorites near the hole that developed in its thick sheet of ice.
Grokhovsky said the tiny rock’s find came in the snow not far away from the lake. He also expressed confidence that a much larger meteorite was buried in its waters.
The lake “is still cordoned off, but it is quite clear that a meteorite is buried there,” the scientist said.
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MW-2 2018...22nd April
MW-3 2018...3rd May
MW-3 Part 2... MW-4 2018 Quantum...20th May
Annual Summary ....2017
Importance of 200 jet streams...The Initial Weather maker...the King:....27th December 2017
A rare and unusual phenomena few days ago...Pink Auroras !...25th November 2017
von Karman Vortices....26th October 2017
Why the Yellow Colour before a ThunderStorm ?...13th October 2017
Secrets of Weather Forecasting Models....Exposed !...27th April 2017
10 years Celebrations of vagaries....17th July 2016
The Crucial 2016 Monsoon....3rd June 2016
Historical High for India..51c on 19th May 2016
World Water Day...22nd March 2016
More first time snow in New Regions...Kuwait and Thailand...30th January 2016
El Nino 2015/2016...Event of the Century...28th January 2016
Hopes Rise if El Nino Eases: ...23rd february 2016
Wither Global Warming... 2014 v/s 2015 Antartic Ice Extent...11th January 2015
There's a Heat Wave in the North Pole..Storm hit the Pole ...2nd january 2016
Achievment of 1 Million Hits...15th October 2015
Weather Events of 2013....
El Nino La Nina and Enso..Simplified 2nd Febraury 2014
SWM Withdrawal note..article of 19th August 2013
What is a drought Year ?....article of 27th March 2013
Indian Monsoon: What’s brewing in the Pacific is more likely a Modokai than a normal El Niño
Indian Monsoon: What’s brewing in the Pacific is more likely a Modokai than a normal El Niño...Article written by Rajan and Vagaries.....17th July 2012
Is India Really Water Starved ?.....July 2012
Importance of Monsoon Forecast for India..March 19th 2012
North Pole Pics.....taken from aircraft over the North Pole on 5th April 2012.
MW-1 2016...10th April
MW-3 2015...30th April
MW-3 Add...2nd May 2015
MW-1 to MW-6 2015
MW-1 2014 10th April
MW-1 2013 ..10th April
MW-3 Add...2013...30th April
MW-4 Part I 2013...6th May
MW-5 ..2013...17th May
MW-6 2013..24th May
NEM Notes 2010
NEM Notes 2011
Direct Links to Previous Articles written in 2009 by the author on :Global Warming"..if it exists !
Ice cover of Artic (Jan 2016) shown in a Satellite image..Though this winter was "Above Normal"..This Image and Recent Events speak in differently.. 2nd March 2016
What is the Rationale behind GW ?...March 2013
Global Warming..Note on...Dec 2009
Global Warming -2...Dec 2009
Global Warming -3..Dec 2009
Global Warming -4 ..Dec 2009
Global Warming - 5 Dec -2013
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What is a Drought Year ? With 7.6% Deficient (All India), would 2012 be termed as a drought Year ?..27th March 2013 (comments on that page)
Droughts in India has resulted in tens of millions of deaths over the course of the 18th, 19th, and 20th centuries. Indian agriculture is heavily dependent on the Monsoons in India: a favorable southwest summer monsoon is critical in securing water for irrigating Indian crops.
Some of the major drought-prone regions are southern and eastern Maharashtra, northern Karnataka, Andhra Pradesh, Orissa, Gujarat, Bengal, Bihar and Rajasthan.
But why has this been repeatedly happening since the last 200 years? 200 years is a long enough period given to overcome the situation and prevent the people's suffering by providing adequate means and inter regional water storage and transfer.
And knowing the weather, it is almost natural, that either of the above mentioned regions is bound to get below normal deficient rainfall in any year. Do we literally have to wait for a surplus rainfall in each and every region of the country. If yes, than thats poor management and governance of water resources.
We should be capable with providing the shortfall by the excess available in some other region. Nature's bounty is always merciful on us, but are we ever ready?
Do we know how to store and preserve water, rather than just let it drain in the two seas on either side. Most of the SWM rains drain off in the seas.
Is India really water starved ? This article ( July 2012) published in Vagaries is most apt and suited for the topic under discussion....and the article ended with ..otherwise .....Otherwise we see the same old story in parts of the country today.
Then what is a drought Year ? Was 2012 a drought Year ?
Out of the total 36 meteorological subdivisions, 23 subdivisions constituting 67.3% of the total area of the country received excess/normal season rainfall and the remaining 13 subdivisions (32.7% of the total area of the country) received deficient season rainfall.
To really analyse the "drought" situation this year, let us take into consideration of the five Peninsula states... TN, Kerala, Gujarat, Maharashtra and Karnataka, which, the officials tell us are the worst effected...
Karnataka: End Season, Coastal Karnatak was 0%, N.I.Karnataka was -36% and S.I.Karnataka was -23%.
Average deficiency for the state: -19.6%.
Maharashtra: End Season: Konkan -3%, Madhya Maharashtra -25%, Marathwada -33% and Vidharbha +8%.
Average State deficiency: -17.6%
Gujarat: Saurashtra and Kutch:-34%, Gujarat Region: -28%.
Average State deficiency: -31%.
Tamil Nadu State Deficiency: -23%. And Kerala -24%.
It can be noticed, from the above figures and map, that the drought regions are all "linked " to each other North/South. Providing and implementing the waters from the coastal regions to the interiors would have been a boon and would have mitigated the losses.
The severest amongst them is Gujarat. However, Gujarat has somewhat marginally lessened the woes by diverting the river waters to water starved Saurashtra and Kutch. Remember, Saurashtra by itself is deficient by -43% !
Maharashtra reservoirs are showing levels as follows as per latest levels available..
Konkan Reservoirs 55%full (last year at this date 49%), Marathwada 10% (24%), Nagpur 37% (35%), Pune 35% (39%).
Overall Maharastra Reservoirs: 32% (36% in 2012 and 50% in 2011).
Situation is manageable and could be kept under control.
Now, in the modern day and era, we have to consider the average of all the regions. The overall Monsoon performance is taken considering India as a whole..Excess and deficient regions. Any developing and established nation like ours would have considered the excess rains that its coastal/mountainous belt gets, to divert the huge amounts of water to its interiors.
The coastal regions of Maharashtra and Karnataka get between 2000-6000 mms, and a few places even boast of over 7500-8000 mms as normal..now that's a fantastic amount of rain by any standards.
Maharashtra has Mahableshwar with five rivers running and originating from there, and from Nasik district the state has the Godavri river, running through the water starved regions of Marathwada !
The State has ample scope to put things in perspective, by irrigating the "normally" low rainfall regions. The state would never complain of a water scarcity !!
July 17th 2012 from Rajan'Take:
Indian Monsoon: What’s brewing in the Pacific is more likely a Modokai than a normal El Niño
Just when it looked as if a traditional El Niño was getting its sea legs, the event is now looking a bit less canonical. This prompted the following analysis. This post is jointly written by Rajan Alexander who administers the blog, Rajan’s Take: Climate Change and Rajesh Kapadia who administers the blog, Vagaries of the Weather.
The Indian press has been going gaga, spreading hysteria about the supposedly El Niño effect messing up the current monsoon. After June whetted their appetites of gloom with very poor rains, their prophecy of doom has now hit a huge speed break with the apparent monsoon revival seen so far this month.Bob Tisdale is perhaps one of the world’s best known authorities on sea-surface temperatures and related oceanic climate phenomena. In his blog he observed that an analysis of historical data suggests that the (summer) El Niño usually crossed its threshold values by late May. This year, it did so only by June second week. Since theoretically there is a time lag of at least 3 months for any El Niño effect to significantly impact the monsoon, this delay could give the current monsoon season a reprieve of sort.Going by the current rate of El-Nino development, the earliest it can impact the monsoon is most likely by beginning of September, a month which accounts for less than 16% of total rainfall of the South West Monsoon (SWM). This also raises hope that August rainfall may have a fair chance of recording “near” normal rainfall viz. around 93-95% of Long Period Average (LPA).Comparison of the evolutions of El Niño eventsBob Tisdale’s latest post compared the current El Niño’s evolution with others historically. The following are his findings:1. NINO3.4 sea surface temperature anomalies (a commonly used ENSO index) have been above the +0.5 deg C threshold of an El Niño for 4 weeks. While it’s far from an “official” El Niño, it appears that it’s likely to become one.
The first thing that stands out in the graph is how there really is nothing typical about the evolution of El Niño events. Five started from ENSO-neutral conditions; that is, with NINO3.4 sea surface temperature anomalies between -0.5 and +0.5 deg C.
Five, including the current one, started from La Niña conditions, with the NINO3.4 sea surface temperatures cooler than -0.5 deg C. And there’s the outlier, the 1987/88 portion of the 2-year 1986/87/88 El Niño.Other than having the coolest NINO3.4 sea surface temperature anomalies at one point, there’s nothing remarkable about the evolution of the NINO3.4 sea surface temperature anomalies this year.
2. The graph below compares the evolution of the El Niño events that started from La Niña conditions. This year’s NINO3.4 sea surface temperature anomalies had been tracking along at the pace of the most recent El Niño, the one that occurred in 2009/10, until recently. Over the past two weeks, NINO3.4 sea surface temperature anomalies have been cooling.
3. NINO3.4 sea surface temperature anomalies appear as though they’re being suppressed by the cooler-than-normal waters being circulated southward from the North Pacific, which should be feedback from the back-to-back La Niña events.It will be interesting to see how long the cooler waters from the North Pacific can suppress the central sea surface temperatures in the east-central equatorial Pacific.
4. The NINO1+2 region is in the eastern tropical Pacific, just south of the equator. The coordinates are 10S-0, 90W-80W. This year the NINO1+2 sea surface temperature anomalies warmed before the NINO3.4 region, but they also have been cooling.
5. There’s still a pocket of elevated anomalies at depth in the eastern equatorial Pacific, and there’s a long way to go before the peak of the ENSO season.
El Niño Modokai
Till recently, it was thought that the El Niño had only one mode - a periodic warming in the eastern tropical Pacific that occurs along the coast of South America. In 2004, it was discovered to have also a second mode that occurs around 12% of the time.A Japanese team led by T. Yamagata (that included a prominent Indian climatologist, Dr Venkata Ratnam) noticed the 2004 El Niño was warming more strongly in the Central Pacific region and accordingly stumbled on the discovery of its second mode by sheer accident. They called such an El Nino as Modokai, which is a classical Japanese word which means“similar but different”. The phenomenon is also known as a Pseudo or Central Pacific (CP) El Niño. It was then adopted by K Ashok and colleagues in a 2007 Journal of Geophysical Research paper to refer to central-Pacific–weighted El Niños more generally. Its basic signature is as follows:1. Weakening of equatorial easterlies related to weakened zonal sea2. Surface temperature gradient lead to more flattening of the thermocline.The US, CPC-International Research Institute in a press note said average sea sub-surface temperatures persisted in thefar eastern Pacific and had recently spread westwards. This has taken place in the eastern half of the equatorial Pacific but recent values of upper ocean heat anomalies continue to reflect ENSO neutral conditions. Equatorial sea surface temperatures (SST) are greater than 0.5°C above average across the eastern Pacific Ocean though the atmospheric circulation over the tropical Pacific reflects cool-to-neutral ENSO conditions.So there we have sort of a confirmation that the Niño is moving westwards instead of the typical eastward direction.
Further - just when it looked as if a traditional El Niño was getting its sea legs, the event is now looking a bit less canonical. Just take a look at last week’s US-CFS v2 forecasts for Niño regions 1+2 from where it could be observed that the warmest anomalies have been centred in the eastern portion of the ENSO monitoring area.
However, as also seen in the forecast, there is now more of a potential for the temperatures to be much lower. One explanation is that the Niño maybe dying off!! The only other explanation is that the heat is merely transferring westwards - a fact validated through the latest SST departures. The western bias to this summer’s warming pattern is what brings to suspect an El Niño Modoki development rather than a typical El Niño.
The question is that if the heat transfer is taking place westward instead of eastward as typically, are we seeing an El Niño Modoki developing instead of a normal El Niño as commonly assumed? This is not easy to answer as Niño regions 1+2 also appears now to be cooling off along with NINO3.4 SSTs. However such cooling could be temporary and not unusual.So what’s an El Niño Modokai?But before we can understand El Niño Modokai variant we need to have to understand El Niño itself. It is part of the El Niño-Southern Oscillation (ENSO) that alternately gives us warm El Niños and cool La Niñas.An ENSO is a physical oscillation of ocean waters from side to side of the tropical Pacific Ocean. It is kept going by trade winds that push the water westwards along the north and south equatorial currents. Between these two currents is the equatorial counter current and the water piled up in the western Pacific eventually comes back east via that counter current. It does so periodically as a massive wave, observable as a Kelvin wave, because the oscillation is caused by wave resonance and the resonance period is determined by the dimensions of the ocean basin.As and when an El Niño wave reaches South America at the equator it splashes ashore and spreads out. This creates a large area of warm water, the air above gets warm, an updraft forms that interferes with trade winds, and global temperature rises by half a degree Celsius. But any wave that runs ashore must also pull back. As the El Niño wave retreats water level behind it drops half a meter or more, cold water from below wells up to fill the space, and a La Niña gets started.But in the case of Modokai, only 20% of the time a La Niña emerges. More often, the Niño dips below the La Niña threshold, but do not remain there long enough to be considered an official La Niña. So if an El Niño Modokai is indeed confirmed this year, it is most likely next year we should be having an ENSO neutral year, rather than a La Niña year. This means, if the El Niño factor is considered as the prime one, we can expect 2013 monsoon season to be within the normal-above average range.Modokai is but a chaotic variation of a typical El Niño pattern, absent the current gyres that usually form at the eastern terminus. This unique warming in the central equatorial Pacific associated with a horse-shoe pattern is flanked by a colder sea surface temperature anomaly (SSTA) on both sides along the equator. This year, as seen in the above graph, there is a lot of cold water circulating from Alaska down the west coast of Canada, the US and Mexico. This cold water is mixing with equatorial Pacific waters and keeping SSTs in equatorial Pacific down.The real difference between the normal El Niño and El Niño Modokai isn’t their locale within the Pacific, it is the mode of energy release and it’s spreading out. The former is predominantly a localised event at the sea surface, because a huge spike in humidity which traps emerging energy and spreads it globally via the resulting winds.Whereas El Niño Modokai is more a global emission of energy from the ocean, resulting in a general humidity increase worldwide rather than a localised blanket of water vapour around a localised emission event, followed by rapid heat loss to space once the warm air is spread out. That is why lower tropospheric temperatures can be expected to remain high as long as 4-6 months after the Pacific event petered out.So from this month to maybe first quarter next year, global temperatures maybe expected to spike moderately and maybe the last hurrah for global warmists. Once the event is over, global lower tropospheric temperatures can be expected to fall very fast, particularly once the NH winter kicks in. Due to the loss of humidity over the cold land masses; the 2014 northern hemisphere winter could be expected to be extremely cold.El Nino Modokai’s Effect on WeatherIn a paper by Venkata Ratnam et al entitled “Pacific Ocean Origin for the 2009 Indian Summer Monsoon Failure”; effect the following were postulated as effects of El Niño Modokai on weather:
During the boreal (northern hemisphere) summer season rainfall anomalies during the June-September season of the seven positive El Niño Modoki years 1986, 1990, 1991, 1992, 1994, 2002, and 2004. Statistically significant surplus rainfall anomalies are seen in the central equatorial Pacific region flanked on both sides by the negative rainfall anomalies in the equatorial western and eastern Pacific.The atmospheric condition associated with the western pole located in the equatorial western Pacific is strongly suspected of influencing rainfall from Indonesia, Malaysia, Singapore etc, with the teleconnection extending northwest up to south India and also Sri Lanka.The teleconnection associated with the positive rainfall anomaly in the central pole (equatorial central Pacific) seems to extend westward via the Philippines, Myanmar to northern eastern India.In the East Asian region, southern Japan suffers droughts during these years owing to the Pacific-Japan pattern [cf. Nitta, 1987]. The deficit rainfall in the western Pacific region is seen to extend southward to southeastern Australia, influencing a significant part of eastern Australia. The negative rainfall anomalies over the equatorial eastern Pacific extend over western coast of North America.The result in the Pacific Ocean is less wind shear and therefore more hurricanes/cyclones - the warmer water is also a necessary factor. The result in the Atlantic Ocean is more wind shear and fewer hurricanes/cyclones.El Niño Modokai Index (EMI)
The Japan Agency for Marine-Earth Science & Technology (Jamstec) developed an El Niño Modokai Index (EMI) as above. The index currently shows that the EMI is still weakly negative but expected to turn weakly positive by this month end or during August.
An El Nino Modoki event is called ‘typical’ when its amplitude of the index is equal to or greater than 0.7α, where α is the seasonal standard deviation. This means even if what is developing is indeed an El Nino Modoki though presently mistakenly assumed an El Niño , this could be confirmed at the earliest only by end of September or October though we could possibly have the first preliminary indication by August end.Past Impact of El Niño Modokai (summer) on Indian Monsoon
Seasonal rainfall wise, there seem to be alot of variation within El Niño Modokai years ranging 769.9 (87%) to 1,001 mm (113%) of rainfall of Long Period Average (LPA). The average however is 845 mm or 95% of LPA.
Instead of around 175 mm average rainfall for June, this year the country received 115.5 mm or a 29% deficiency. If this year is indeed an El Niño Modokai year, then this should be a new record low relegating 1986 to second place.With June rainfall poor, does it mean rainfall would get progressively worse? Let’s look at 1992, presently occupying the bottom rung with a 27% rainfall deficiency in June. At the end of the season it still managed to reduce the deficiency to 6% overall. So it is possible that July-September rains to be normal even if June rains fail.However, this is a simplistic analysis. The performance of the monsoon will depend on other variables such the behaviour of the Indian Ocean Dipole (IOD); Madden Julian Oscillation (MJO), summer temperatures, snow cover, Mascaerne Highs, etc. Nevertheless let’s use the same technique to understand what possible impact El Niño Modoki could have in relation spatial distribution of rainfall as demonstrated historically.
We find that North India, both east and west, relatively tend to suffer a higher rainfall deficiency as compared to the Southern Peninsular with Central India coming out practically unscathed.ConclusionWhat we can conclude with high confidence is that with the El Niño crossing threshold values two weeks later than normal, this is likely to be a positive development in relation to rainfall for rest of the monsoon season.Should the El Niño be of the Modokai variant, then its adverse impact on rainfall is most likely to be relatively weaker than those of a normal El Niño.It is too early to confirm the development of an El Niño Modikai this season. We should have better idea by mid August but an official confirmation would be possible only after the monsoon season ends. | <urn:uuid:d865258c-4c7b-4836-87f5-a9be37ff25e5> | 2.84375 | 4,960 | Content Listing | Science & Tech. | 60.57052 | 95,531,784 |
It's Not a Game
Putting a computer on Jeopardy! warps the public understanding of what artificial intelligence is and how science is done.
Watching the computer system known as Watson defeat the top two human Jeopardy! players of all time was fun in the short term. This demonstration of IBM’s software, however, was a bad idea in the longer term. It presented a misleading picture to the public of what is known about machine and human intelligence, and more seriously, it advanced a flawed approach to science that stands to benefit the enemies of science.
There’s a crucial distinction to make right away. My purpose is not to criticize the work done by the team that created Watson. Nor do I want to critique their professional publications or their interactions with colleagues in the field of computer science. Instead, I am concerned with the nature of the pop spectacle hatched by IBM.
Why was there a public spectacle at all? Certainly it’s worthwhile to share the joy and excitement of science with the public, as NASA often does. But there were no other Mars rovers to compare with the NASA rovers when they landed, and there is a whole world of research related to artificial intelligence. By putting its system on TV and personifying that system with a name and a computer-generated voice, IBM separated it from its context, suggesting—falsely—the existence of a sui generis entity.
Contrast IBM’s theatrics with the introduction of Wolfram Alpha, a “knowledge engine” for the Web that physicist Stephen Wolfram released in 2009 (see “Search Me,” July/August 2009). Although the early rhetoric around Alpha was a touch extreme, sometimes exaggerating its natural-language competence, the method of introduction was vastly more honest. Wolfram Research didn’t resort to stage magic: Alpha was made available online for people to try. Stephen Wolfram encouraged people to use his technology and compare the results with those generated by search engines like Google. Alpha proved honestly that it was something fresh, different, and useful. Comparison with what came before is crucial to progress in science and technology.
- IBM’s Watson on Jeopardy! February 14–16, 2011
But Watson was presented on TV as an entity instead of a technology, and people are inclined to treat entities charitably. You are more likely to give a “he” the benefit of a doubt, while you judge an “it” for what it can do as a tool. Watson avoided any such comparative judgment, and the public wasn’t given a window into what would happen in that kind of empirical process. Stephen Wolfram himself, however, went to the trouble of writing a blog post comparing Watson with everyday search engines. He entered the text of Jeopardy! clues into those search engines and found that in many cases, the first document they returned contained the answer. Identifying a page that contains the answer is not the same thing as being able to give the answer on Jeopardy!, but this little experiment does indicate that Watson’s abilities were less extraordinary than one might have gathered from watching the broadcast.
Wouldn’t it have been better to open the legitimate process of science to the public instead of staging a fake version? An example of how to do this was the DARPA-sponsored “Grand Challenge” to create self-driving cars. By pitting technologies against each other, DARPA informed the public well and offered a glimpse into the state of the art. The contest also made for great TV. Competitors were motivated. The process worked.
The Jeopardy! show in itself, by contrast, was not informative. There are a multitude of open questions about how human language works and how brains think. But when machines are pitted against people, an unstated assertion is inevitably propagated: that human thinking and machine “intelligence” are already known to be at least comparable. Of course, this is not true.
In the case of Jeopardy!, the game’s design isolates a specific skill: guessing words on the basis of hints. We know that being able to guess an unstated word from its context is part of language competency, but we don’t know how important that skill is in relation to the whole phenomenon of human language. We don’t fully know what would be required to re-create that phenomenon. Even if it had been stated (in fine print, as it were) that the task of competing at Jeopardy! shouldn’t be confused with complete mastery of human language, the extravaganza would have left the impression that scientists are on a rapid, inexorable march toward conquering language and meaning—as if a machine that can respond like a person in a particular context must be doing something similar to what the human brain does.
Much of what computer scientists were actually doing in this case, however, was teaching the software to identify statistical correlations in giant databases of text. For example, the terms “Massachusetts,” “university,” “technology,” and “magazine” will often be found in documents that also contain the term “Technology Review.” That correlation can be calculated on the fly to answer a Jeopardy! question; similar methods have proved useful for search engines and automated help lines. But beyond such applications, we don’t know where this particular line of research will lead, because recognizing correlations is not the same as understanding meaning; a sufficiently large statistical simulation of semantics is not the same thing as semantics. Similarly, you could use correlations and extrapolations to predict the next number in a given numeric sequence, but you need deeper analysis and mathematical proof to get it right every time. Goodstein sequences are sequences of numbers that seem to always go up—until eventually they revert and fall to zero. A prediction based on statistical analysis of the early phase of such a sequence would get the rest of the sequence wrong. Correlations can simulate understanding without really delivering it.
Ultimately, does the Watson show really matter? Why not let IBM’s PR people enjoy a day in the sun? Here’s why not: there is a special danger when science is presented to the public in a sloppy way. Technical communities must exhibit exemplary behavior, because we are losing public legitimacy in the United States. Denying global climate change remains respectable in politics; many high-school biology teachers still don’t fully accept evolution.
Unfortunately, the theatrics of the Jeopardy! contest play the same trick with neuroscience that “intelligent design” does with evolution. The facts are cast to make it seem as though they imply a metaphysical idea: in this case, that we are making machines come alive in our image.
Indeed, that is a quasi-religious idea for some technical people. There’s a great deal of talk about computers inheriting the earth, perhaps in a “singularity” event—and perhaps even granting humans everlasting life in a virtual world, if we are to believe Ray Kurzweil.
But even if we quarantine overtly techno-religious ideas, the Watson-on-Jeopardy! scheme projects an alchemical agenda. We say, “Look, an artificial intelligence is visible in the machine’s correlations.” A promoter of intelligent design says, “Look, a divine intelligence is visible in the correlations derived from sources like fossils and DNA.”
When we do it, how can we complain that others do it? If scientists desire respect from the public, we should expect to be emulated, and we should be careful about what methods we present for emulation.
Jaron Lanier is a computer scientist, writer, and musician. His most recent book is You Are Not a Gadget (Knopf, 2010). He is a partner architect at Microsoft Research and the innovator in residence at the Annenberg School of USC. His name has been used in a Jeopardy! clue.
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Rare meteorite that lit up Arizona sky receives tribal name
PHOENIX — A rare meteorite that crashed into Native American land after lighting up the skies over Arizona last year has been given a tribal name.
Arizona State University said the meteorite’s full name is Dishchii’bikoh Ts’iłsǫǫsé Tsee, which is Apache for Cibecue Star Rock. The meteorite was found near the town of Cibecue, which is on Apache land in eastern Arizona.
About 15 pieces of the rock were recovered less than a month after they fell to Earth by a team of ASU researchers. It is thought the pieces came from a meteor about the size of a Volkswagen Beetle that entered the atmosphere moving about 40,000 mph.
The meteorite was one of only 50 of its type that have been found in the world. Dishchii’bikoh is the first in North America.
Though the meteorite is a chondrite — the most common type of meteor — it does have some unusual features.
“In one respect it’s an ordinary chondrite, but when we looked at the structure there’s aspects we’ve never seen before. This is where the future scientific analysis will take place,” Laurence Garvie, research professor and curator of the Center for Meteorite Studies in the School of Earth and Space Exploration, said in a press release.
Garvie said the identification and naming processes took about one year to complete.
“It’s something the public knows almost nothing about,” he said. “It’s a lot of work. It’s not just me eyeballing it saying, ‘It’s a whatever.’ It’s hours of work here and hours of work on microscopes and hours of work looking through boring Excel spreadsheets.”
“Then you have to write a report and then you have to submit it to the nomenclature committee and then, assuming everything is OK, you have to publish your findings. So it’s a long, long process.”
The meteorite belongs to the tribe, but it has agreed to allow it to be curated in perpetuity at ASU’s Tempe campus.
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When it comes to trying to model the properties and behavior of systems of atoms, scientists use two fundamentally different pictures of reality, one of which is called 'statistical' and the other 'dynamical'. The two approaches have at times been at odds, but scientists announced a way to reconcile the two pictures.
Researchers have successfully demonstrated charge transport between Nitrogen-Vacancy color centers in diamond. The team developed a novel multi-color scanning microscopy technique to visualize the charge transport.
Engineers discover that samarium nickelate shows promise for active photonic devices - SmNiO3 could potentially transform optoelectronic technologies, including smart windows, infrared camouflage, and optical communications.
Scientists have developed a simple and effective method for the formation of robust covalent ONTs from simple molecules. This method is expected to be useful in generating a range of nanotube-based materials with desirable properties.
Researchers have discovered a type of drug delivery system that may offer new hope for patients with a rare, ultimately fatal genetic disorder - and make what might become a terrible choice a little easier.
Scientists have engineered a novel nanoscale drug delivery vehicle which can be tuned to release a range of cargos. The drug delivery system consists of self-assembled DNA nanopores embedded in nanometre-sized 'bubbles' known as polymersomes. | <urn:uuid:41d6e91c-85c9-4efb-aa23-53ca5925fdf5> | 2.71875 | 277 | Content Listing | Science & Tech. | 8.933981 | 95,531,841 |
Primates can influence seed dispersal and spatial genetic kinship structure of plants that serve as their food source. This is the result of a cooperation project of behavioral ecologist Eckhard W. Heymann from the German Primate Center (DPZ) with plant geneticists Birgit Ziegenhagen and Ronald Bialozyt from the Philipps-University Marburg. This study was funded by the German Research Foundation (Bialozyt et al., Trees, 2014).
At the DPZ-field station Estación Biológica Quebrada Blanco in the Peruvian Amazonian lowlands, scientists studied how feeding, sleeping, and ranging habits of two species of New World monkeys affect the dispersal of the neotropical legume tree Parkia panurensis.
Moustached tamarins (Saguinus mystax) contribute crucially to the seed dispersal of the neotropical tree Parkia panurensis. Photo: Julia Diegmann
For this, the researchers observed a group of Brown-mantled tamarins (Saguinus nigrifrons) and Moustached tamarins (Saguinus mystax), who jointly moved through home ranges in search of edible plants which included Parkia trees.
Fruits from these trees are pods that contain 16 to 23 seeds, each of which is surrounded by edible gum. The monkeys feed on the gum content of the pods and at the same time swallow the Parkia seeds which are later defecated intact in a different area.
During behavioral observations, researchers recorded the food intake of tamarins as well as the location of the Parkia trees that they visited. In addition, they collected faecal samples of the tamarins that contained seeds. “With the help of genetic analyses of the DNA found in the seed coat, which is of maternal origin, we could make an exact assignment of the corresponding “mother tree” for the seeds”, says Eckhard W. Heymann from the DPZ. "This allowed us to determine how far Parkia seeds were dispersed by the monkeys."
In order to analyze the effect of seed dispersal by monkeys on a spatial genetic level, the scientists examined three different developmental stages of the trees. In addition to the seeds that contain the plant embryo, they collected leaves from young and mature Parkia trees in the home range of tamarins. “With the help of analysis from microsatellites, short repeated DNA sequences, we were able to identify genetic similarities of individual trees”, says Heymann.
The analysis of the spatial genetic structure of the Parkia population revealed a significant genetic relationship of the plant embryos and young trees within a radius of 300 meters, which coincides with the distance within which most seeds are dispersed by the tamarins. For mature trees, the relationship was reduced to a radius of only up to 100 meters.
"In tropical rain forests, the seeds of 80 to 90 percent of trees and lianas are dispersed by animals. In addition to primates, birds and bats are the major animal groups that are responsible for seed dispersal”, says behavioral ecologist Heymann. “For the plants, transport of their seeds is extremely important. As sedentary organisms, this is the only way that their offspring - the embryos contained in the seeds - can reach appropriate sites for germination and growth. Furthermore, this reduces the density-dependent mortality which occurs when the seeds fall under the mother plants,” says Eckhard W. Heymann. Fruit-eating primates such as tamarins are therefore invaluable to the natural regeneration and diversity of ecosystems in which they live.
Bialozyt, R., Lüttmann, K., Michalczyk, I.M., Saboya, P.P.P., Ziegenhagen, B., Heymann, E.W. (2014): Primate seed dispersal leaves spatial genetic imprint throughout subsequent life stages of the Neotropical tree Parkia panurensis. Trees DOI 10.1007/s00468-014-1061-7 (open access)
Prof. Dr. Eckhard W. Heymann
Tel: +49 551 3851-123
Dr. Susanne Diederich (Communication Department)
Tel: +49 551 3851-359
http://link.springer.com/article/10.1007%2Fs00468-014-1061-7#page-1 - Link to the original publication
Dr. Susanne Diederich | idw - Informationsdienst Wissenschaft
Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides
16.07.2018 | Tokyo Institute of Technology
The secret sulfate code that lets the bad Tau in
16.07.2018 | American Society for Biochemistry and Molecular Biology
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Discovery marks culmination of decades-long search for elusive particles
Physicists in Syracuse University's College of Arts and Sciences have confirmed the existence of two rare pentaquark states. Their discovery, which has taken place at the CERN Large Hadron Collider (LHC) in Geneva, Switzerland, is said to have major implications for the study of the structure of matter.
It also puts to rest a 51-year-old mystery, in which American physicist Murray Gell-Mann famously posited the existence of fundamental subatomic constituents called quarks, which form particles such as protons. In 1964, he said that, in addition to a constituent with three quarks, there could be one with four quarks and an anti-quark, known as a "pentaquark." Until now, the search for pentaquarks has been fruitless.
"The statistical evidence of these new pentatquark states is beyond question," says Sheldon Stone, Distinguished Professor of Physics, who helped engineer the discovery. "Although some positive evidence was reported around 10 years ago, those results have been thoroughly debunked. Since then, the LHCb [Large Hadron Collider beauty] collaboration has been particularly deliberate in its study."
In addition to Stone, the research team includes other physicists with ties to Syracuse: Tomasz Skwarnicki, professor of physics; Nathan Jurik G'16, a Ph.D. student; and Liming Zhang, a former University research associate who is now an associate professor at Tsinghua University in Beijing, China.
Liming, in fact, is presenting the findings at a LHCb workshop on Wednesday, July 22, at CERN.
Stone credits Gell-Mann, a Nobel Prize-winning scientist who spent much of his career at Caltech, for postulating the existence of quarks, which are fractionally charged objects that make up matter. "He predicted that strongly interacting particles [hadrons] are formed from quark-antiquark pairs [mesons] or from three quarks [baryons]," Stone says. "This classification scheme, which has grown to encompass hadrons with four and five quarks, underscores the Standard Model, which explains the physical make-up of the Universe."
Stone says that, while his team's discovery is remarkable, it still begs many questions. One of them is the issue of how quarks bind together. The traditional answer has been a residual nuclear force, approximately 10 million times stronger than the chemical binding in atoms.
But not all bindings are created equal, Skwarnicki says. "Quarks may be tightly bound or loosely bound in a meson-baryon molecule," he explains. "The color-neutral meson and baryon feel a residual strong force [that is] similar to the one binding nucleons to form nuclei."
Adds Stone: "The theory of strong interactions is the only strongly coupled theory we have. It is particularly important for us to understand, as it not only describes normal matter, but also serves as a precursor for future theories."
The discovery is the latest in a string of successes for Syracuse's Department of Physics, which made international headlines last year, when Skwarnicki helped prove the existence of a meson named Z(4430), with two quarks and two antiquarks.
Much of this cutting-edge work occurs at CERN, where Stone oversees more than a dozen Syracuse researchers. CERN houses four multinational experiments, each with its own detector for collecting data from the LHC particle accelerator.
Rob Enslin | EurekAlert!
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
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16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences | <urn:uuid:ec1a52eb-0f20-416b-8c9b-28ed434cd9f6> | 2.90625 | 1,384 | Content Listing | Science & Tech. | 39.40993 | 95,531,875 |
BERLIN – Scientists have used a laser to tickle atoms of antimatter and make them shine, a key step toward answering one of the great riddles of the universe.
Theory predicts that the Big Bang produced equal amounts of matter and antimatter. Since they cancel each other out, scientists have been trying to find out why a relatively small amount of matter remained – allowing the stars, planets and ultimately life as we know it to come about – and antimatter vanished.
It took researchers at the European Organization for Nuclear Research, or CERN, decades to figure out how to create an antimatter version of the most basic atom – hydrogen – and trap it for long enough to perform tests.
In a paper published online Monday by the journal Nature, they reported the first cautious result from an experiment with antihydrogen. It turns out that when it’s stimulated with a laser, antihydrogen appears to produce light on the same ultraviolet frequency as its nemesis in the world of matter, hydrogen.
Adding energy – in this case with a laser – to atoms to see what light they absorb and emit is known as spectroscopy. It is a commonly used tool in physics, chemistry and even astronomy, to determine the atomic composition of substances in a lab or even far-away galaxies. The results can be presented as rainbow-like panels or as graphs showing the distribution of certain colors.
“What we have is one color,” said Jeffrey Hangst, a leading member of the team working on the ALPHA experiment at CERN , which is located on the Swiss-French border. “But it’s kind of the most fundamental one because it’s the one that we can measure most accurately.”
Hangst and his colleagues now plan to refine the experiment, using techniques developed for hydrogen over the past 200 years, to map in precise detail the atomic spectrum of antihydrogen.
“All we’ve done so far is find the top of the hill, now we want to measure the shape of the hill,” he told the Associated Press.
Guido Drexlin, a physicist at the Karlsruhe Institute of Technology who wasn’t involved in the study, said scientists had been eagerly awaiting the results of the CERN experiment for years. “They are on a good track,” he said.
Successfully discovering a difference between matter and antimatter would be worthy of a Nobel Prize, said Drexlin. “The differences between matter and antimatter are extremely subtle,” he said. “There is a slight preference for matter and we would like to know why.”
Hangst, who is also at Aarhus University in Denmark, said the team at CERN is working on new experiments, including one that looks at how antihydrogen is affected by gravity.
“We’re going to make a machine that’s vertical, and then we’re going to trap antihydrogen and drop it,” he said.
One of the great hurdles for researchers is the fact that producing antihydrogen is still a painstaking process that yields just over a dozen atoms each time.
But Hangst said the team has come a long way since it proposed the experiment some 20 years ago, including in the eyes of some peers.
“There was a time when this was kind of the lunatic fringe of physics,” he said. | <urn:uuid:93b9be5d-adc5-4299-bf5b-02c2c044acce> | 3.5 | 717 | News Article | Science & Tech. | 43.38795 | 95,531,885 |
Full Text Available Coal is the main source of energy. In China and Vietnam, coal resources are very rich, but the exploration level is relatively low. This is mainly caused by the complicated geological structure, the low efficiency, the related damage, and other bad situations. To this end, we need to make use of some advanced technologies to guarantee the resource exploration is implemented smoothly and orderly. Numerous studies show that remote sensing technology is an effective way in coal exploration and measurement. In this paper, we try to measure the distribution and reserves of open-air coal area through satellite imagery. The satellite picture of open-air coal mining region in Quang Ninh Province of Vietnam was collected as the experimental data. Firstly, the ENVI software is used to eliminate satellite imagery spectral interference. Then, the image classification model is established by the improved ELM algorithm. Finally, the effectiveness of the improved ELM algorithm is verified by using MATLAB simulations. The results show that the accuracies of the testing set reach 96.5%. And it reaches 83% of the image discernment precision compared with the same image from Google.
Xu, Lingzhe; Yang, Shihai
Astronomers are ever dreaming of sites with best seeing on the Earth surface for celestial observation, and the Antarctica is one of a few such sites only left owing to the global air pollution. However, Antarctica region is largely unaccessible for human being due to lacking of fundamental living conditions, travel facilities and effective ways of communication. Worst of all, the popular internet source as a general way of communication scarcely exists there. Facing such a dilemma and as a solution remote control and data transmission for telescopes through iridium satellite communication has been put forward for the Chinese network Antarctic Schmidt Telescopes 3 (AST3), which is currently under all round research and development. This paper presents iridium satellite-based remote control application adapted to telescope control. The pioneer work in China involves hardware and software configuration utilizing techniques for reliable and secure communication, which is outlined in the paper too.
Pour, Amin Beiranvand; Park, Yongcheol; Park, Tae-Yoon S.; Hong, Jong Kuk; Hashim, Mazlan; Woo, Jusun; Ayoobi, Iman
Satellite remote sensing imagery is especially useful for geological investigations in Antarctica because of its remoteness and extreme environmental conditions that constrain direct geological survey. The highest percentage of exposed rocks and soils in Antarctica occurs in Northern Victoria Land (NVL). Exposed Rocks in NVL were part of the paleo-Pacific margin of East Gondwana during the Paleozoic time. This investigation provides a satellite-based remote sensing approach for regional geological mapping in the NVL, Antarctica. Landsat-8 and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) datasets were used to extract lithological-structural and mineralogical information. Several spectral-band ratio indices were developed using Landsat-8 and ASTER bands and proposed for Antarctic environments to map spectral signatures of snow/ice, iron oxide/hydroxide minerals, Al-OH-bearing and Fe, Mg-OH and CO3 mineral zones, and quartz-rich felsic and mafic-to-ultramafic lithological units. The spectral-band ratio indices were tested and implemented to Level 1 terrain-corrected (L1T) products of Landsat-8 and ASTER datasets covering the NVL. The surface distribution of the mineral assemblages was mapped using the spectral-band ratio indices and verified by geological expeditions and laboratory analysis. Resultant image maps derived from spectral-band ratio indices that developed in this study are fairly accurate and correspond well with existing geological maps of the NVL. The spectral-band ratio indices developed in this study are especially useful for geological investigations in inaccessible locations and poorly exposed lithological units in Antarctica environments.
Kahn, Ralph A.
Aerosols are solid or liquid particles suspended in the air, and those observed by satellite remote sensing are typically between about 0.05 and 10 microns in size. (Note that in traditional aerosol science, the term "aerosol" refers to both the particles and the medium in which they reside, whereas for remote sensing, the term commonly refers to the particles only. In this article, we adopt the remote-sensing definition.) They originate from a great diversity of sources, such as wildfires, volcanoes, soils and desert sands, breaking waves, natural biological activity, agricultural burning, cement production, and fossil fuel combustion. They typically remain in the atmosphere from several days to a week or more, and some travel great distances before returning to Earth's surface via gravitational settling or washout by precipitation. Many aerosol sources exhibit strong seasonal variability, and most experience inter-annual fluctuations. As such, the frequent, global coverage that space-based aerosol remote-sensing instruments can provide is making increasingly important contributions to regional and larger-scale aerosol studies.
Hasager, Charlotte Bay; Badger, Merete; Astrup, Poul
Satellite remote sensing of ocean surface winds are presented with focus on wind energy applications. The history on operational and research-based satellite ocean wind mapping is briefly described for passive microwave, scatterometer and synthetic aperture radar (SAR). Currently 6 GW installed...
Hasager, Charlotte Bay
the uncertainty on the model results on the offshore wind resource, it is necessary to compare model results with observations. Observations from ground-based wind lidar and satellite remote sensing are the two main technologies that can provide new types of offshore wind data at relatively low cost....... The advantages of microwave satellite remote sensing are 1) horizontal spatial coverage, 2) long data archives and 3) high spatial detail both in the coastal zone and of far-field wind farm wake. Passive microwave ocean wind speed data are available since 1987 with up to 6 observations per day with near...
Blake, R.; Liou-Mark, J.
The U.S. remains in grave danger of losing its global competitive edge in STEM. To find solutions to this problem, the Obama Administration proposed two new national initiatives: the Educate to Innovate Initiative and the $100 million government/private industry initiative to train 100,000 STEM teachers and graduate 1 million additional STEM students over the next decade. To assist in ameliorating the national STEM plight, the New York City College of Technology has designed its NSF Research Experience for Undergraduate (REU) program in satellite and ground-based remote sensing to target underrepresented minority students. Since the inception of the program in 2008, a total of 45 undergraduate students of which 38 (84%) are considered underrepresented minorities in STEM have finished or are continuing with their research or are pursuing their STEM endeavors. The program is comprised of the three primary components. The first component, Structured Learning Environments: Preparation and Mentorship, provides the REU Scholars with the skill sets necessary for proficiency in satellite and ground-based remote sensing research. The students are offered mini-courses in Geographic Information Systems, MATLAB, and Remote Sensing. They also participate in workshops on the Ethics of Research. Each REU student is a member of a team that consists of faculty mentors, post doctorate/graduate students, and high school students. The second component, Student Support and Safety Nets, provides undergraduates a learning environment that supports them in becoming successful researchers. Special networking and Brown Bag sessions, and an annual picnic with research scientists are organized so that REU Scholars are provided with opportunities to expand their professional community. Graduate school support is provided by offering free Graduate Record Examination preparation courses and workshops on the graduate school application process. Additionally, students are supported by college
Lu, Y C; Tian, Q J; Lyu, C G; Fu, W X; Han, W C
An optical remote sensing model has been established based on two-beam interference theory to estimate marine oil slick thickness. Extinction coefficient and normalized reflectance of oil are two important parts in this model. Extinction coefficient is an important inherent optical property and will not vary with the background reflectance changed. Normalized reflectance can be used to eliminate the background differences between in situ measured spectra and remotely sensing image. Therefore, marine oil slick thickness and area can be estimated and mapped based on optical remotely sensing image and extinction coefficient
Welle, P.; Ravanbakhsh, S.; Póczos, B.; Mauter, M.
Human-induced salinization of agricultural soils is a growing problem which now affects an estimated 76 million hectares and causes billions of dollars of lost agricultural revenues annually. While there are indications that soil salinization is increasing in extent, current assessments of global salinity levels are outdated and rely heavily on expert opinion due to the prohibitive cost of a worldwide sampling campaign. A more practical alternative to field sampling may be earth observation through remote sensing, which takes advantage of the distinct spectral signature of salts in order to estimate soil conductivity. Recent efforts to map salinity using remote sensing have been met with limited success due to tractability issues of managing the computational load associated with large amounts of satellite data. In this study, we use Google Earth Engine to create composite satellite soil datasets, which combine data from multiple sources and sensors. These composite datasets contain pixel-level surface reflectance values for dates in which the algorithm is most confident that the surface contains bare soil. We leverage the detailed soil maps created and updated by the United States Geological Survey as label data and apply machine learning regression techniques such as Gaussian processes to learn a smooth mapping from surface reflection to noisy estimates of salinity. We also explore a semi-supervised approach using deep generative convolutional networks to leverage the abundance of unlabeled satellite images in producing better estimates for salinity values where we have relatively fewer measurements across the globe. The general method results in two significant contributions: (1) an algorithm that can be used to predict levels of soil salinity in regions without detailed soil maps and (2) a general framework that serves as an example for how remote sensing can be paired with extensive label data to generate methods for prediction of physical phenomenon.
Full Text Available Precision agriculture is a way to manage the crop yield resources like water, fertilizers, soil, seeds in order to increase production, quality, gain and reduce squander products so that the existing system become eco-friendly. The main target of precision agriculture is to match resources and execution according to the crop and climate to ameliorate the effects of Praxis. Global Positioning System, Geographic Information System, Remote sensing technologies and various sensors are used in Precision farming for identifying the variability in field and using different methods to deal with them. Satellite based remote sensing is used to study the variability in crop and ground but suffer from various disadvantageous such as prohibited use, high price, less revisiting them, poor resolution due to great height, Unmanned Aerial Vehicle (UAV is other alternative option for application in precision farming. UAV overcomes the drawback of the ground based system, i.e. inaccessibility to muddy and very dense regions. Hovering at a peak of 500 meter - 1000 meter is good enough to offer various advantageous in image acquisition such as high spatial and temporal resolution, full flexibility, low cost. Recent studies of application of UAV in precision farming indicate advanced designing of UAV, enhancement in georeferencing and the mosaicking of image, analysis and extraction of information required for supplying a true end product to farmers. This paper also discusses the various platforms of UAV used in farming applications, its technical constraints, seclusion rites, reliability and safety.
Sorek-Hamer, Meytar; Just, Allan C; Kloog, Itai
Particulate matter air pollution is a ubiquitous exposure linked with multiple adverse health outcomes for children and across the life course. The recent development of satellite-based remote-sensing models for air pollution enables the quantification of these risks and addresses many limitations of previous air pollution research strategies. We review the recent literature on the applications of satellite remote sensing in air quality research, with a focus on their use in epidemiological studies. Aerosol optical depth (AOD) is a focus of this review and a significant number of studies show that ground-level particulate matter can be estimated from columnar AOD. Satellite measurements have been found to be an important source of data for particulate matter model-based exposure estimates, and recently have been used in health studies to increase the spatial breadth and temporal resolution of these estimates. It is suggested that satellite-based models improve our understanding of the spatial characteristics of air quality. Although the adoption of satellite-based measures of air quality in health studies is in its infancy, it is rapidly growing. Nevertheless, further investigation is still needed in order to have a better understanding of the AOD contribution to these prediction models in order to use them with higher accuracy in epidemiological studies.
Löwe, Peter; Wächter, Joachim
The Boxing Day Tsunami killed 240,000 people and inundated the affected shorelines with waves reaching heights up to 30m. Tsunami Early Warning Capabilities have improved in the meantime by continuing development of modular Tsunami Early Warning Systems (TEWS). However, recent tsunami events, like the Chile 2010 and the Honshu 2011 tsunami demonstrate that the key challenge for TEWS research still lies in the timely issuing of reliable early warning messages to areas at risk, but also to other stakeholders professionally involved in the unfolding event. Until now remote sensing products for Tsunami events, including crisis maps and change detection products, are exclusively linked to those phases of the disaster life cycle, which follow after the early warning stage: Response, recovery and mitigation. The International Charter for Space and Major Disasters has been initiated by the European Space Agency (ESA) and the Centre National d'Etudes Spatiales (CNES) in 1999. It coordinates a voluntary group of governmental space agencies and industry partners, to provide rapid crisis imaging and mapping to disaster and relief organisations to mitigate the effects of disasters on human life, property and the environment. The efficiency of this approach has been demonstrated in the field of Tsunami early warning by Charter activations following the Boxing Day Tsunami 2004, the Chile Tsunami 2010 and the Honshu Tsunami 2011. Traditional single-satellite operations allow at best bimonthly repeat rates over a given Area of Interest (AOI). This allows a lot of time for image acquisition campaign planning between imaging windows for the same AOI. The advent of constellations of identical remote sensing satellites in the early 21st century resulted both in daily AOI revisit capabilities and drastically reduced time frames for acquisition planning. However, the image acquisition planning for optical remote sensing satellite constellations is constrained by orbital and communication
Including an introduction and historical overview of the field, this comprehensive synthesis of the major biophysical applications of satellite remote sensing includes in-depth discussion of satellite-sourced biophysical metrics such as leaf area index.
Chern, Jeng-Shing; Ling, Jer; Weng, Shui-Lin
FORMOSAT-2 is Taiwan's first remote sensing satellite (RSS). It was launched on 20 May 2004 with five-year mission life and a very unique mission orbit at 891 km altitude. This orbit gives FORMOSAT-2 the daily revisit feature and the capability of imaging the Arctic and Antarctic regions due to the high enough altitude. For more than three years, FORMOSAT-2 has performed outstanding jobs and its global effectiveness is evidenced in many fields such as public education in Taiwan, Earth science and ecological niche research, preservation of the world heritages, contribution to the International Charter: space and major disasters, observation of suspected North Korea and Iranian nuclear facilities, and scientific observation of the atmospheric transient luminous events (TLEs). In order to continue the provision of earth observation images from space, the National Space Organization (NSPO) of Taiwan started to work on the second RSS from 2005. This second RSS will also be Taiwan's first indigenous satellite. Both the bus platform and remote sensing instrument (RSI) shall be designed and manufactured by NSPO and the Instrument Technology Research Center (ITRC) under the supervision of the National Applied Research Laboratories (NARL). Its onboard computer (OBC) shall use Taiwan's indigenous LEON-3 central processing unit (CPU). In order to achieve cost effective design, the commercial off the shelf (COTS) components shall be widely used. NSPO shall impose the up-screening/qualification and validation/verification processes to ensure their normal functions for proper operations in the severe space environments.
Full Text Available This paper will assess the most recently available open access high-resolution optical satellite data (0.3 m–0.6 m and its detection of buried ancient features versus ground based remote sensing tools. It also discusses the importance of CORONA satellite data to evaluate landscape changes over the past 50 years surrounding sites. The study concentrates on Egypt’s Nile Delta, which is threatened by rising sea and water tables and urbanization. Many ancient coastal sites will be lost in the next few decades, thus this paper emphasizes the need to map them before they disappear. It shows that high resolution satellites can sometimes provide the same general picture on ancient sites in the Egyptian Nile Delta as ground based remote sensing, with relatively sandier sedimentary and degrading tell environments, during periods of rainfall, and higher groundwater conditions. Research results also suggest potential solutions for rapid mapping of threatened Delta sites, and urge a collaborative global effort to maps them before they disappear.
Andrew A. Tronin
Full Text Available A wide range of satellite methods is applied now in seismology. The first applications of satellite data for earthquake exploration were initiated in the ‘70s, when active faults were mapped on satellite images. It was a pure and simple extrapolation of airphoto geological interpretation methods into space. The modern embodiment of this method is alignment analysis. Time series of alignments on the Earth's surface are investigated before and after the earthquake. A further application of satellite data in seismology is related with geophysical methods. Electromagnetic methods have about the same long history of application for seismology. Stable statistical estimations of ionosphere-lithosphere relation were obtained based on satellite ionozonds. The most successful current project "DEMETER" shows impressive results. Satellite thermal infra-red data were applied for earthquake research in the next step. Numerous results have confirmed previous observations of thermal anomalies on the Earth's surface prior to earthquakes. A modern trend is the application of the outgoing long-wave radiation for earthquake research. In ‘80s a new technology—satellite radar interferometry—opened a new page. Spectacular pictures of co-seismic deformations were presented. Current researches are moving in the direction of pre-earthquake deformation detection. GPS technology is also widely used in seismology both for ionosphere sounding and for ground movement detection. Satellite gravimetry has demonstrated its first very impressive results on the example of the catastrophic Indonesian earthquake in 2004. Relatively new applications of remote sensing for seismology as atmospheric sounding, gas observations, and cloud analysis are considered as possible candidates for applications.
Faundeen, John L.; Kelly, Francis P.; Holm, Thomas M.; Nolt, Jenna E.
The National Satellite Land Remote Sensing Data Archive (NSLRSDA) resides at the U.S. Geological Survey's (USGS) Earth Resources Observation and Science (EROS) Center. Through the Land Remote Sensing Policy Act of 1992, the U.S. Congress directed the Department of the Interior (DOI) to establish a permanent Government archive containing satellite remote sensing data of the Earth's land surface and to make this data easily accessible and readily available. This unique DOI/USGS archive provides a comprehensive, permanent, and impartial observational record of the planet's land surface obtained throughout more than five decades of satellite remote sensing. Satellite-derived data and information products are primary sources used to detect and understand changes such as deforestation, desertification, agricultural crop vigor, water quality, invasive plant species, and certain natural hazards such as flood extent and wildfire scars.
Raju, P. L. N.; Gupta, P. K.
One of the prime activities of Indian Space Research Organisation's (ISRO) Space Program is providing satellite communication services, viz., television broadcasting, mobile communication, cyclone disaster warning and rescue operations etc. so as to improve their economic conditions, disseminate technical / scientific knowledge to improve the agriculture production and education for rural people of India. ISRO, along with National Aeronautical and Space Administration (NASA) conducted experimental satellite communication project i.e. Satellite Instructional Television Experiment (SITE) using NASA's Advanced Telecommunication Satellite (i.e. ATS 6) with an objective to educate poor people of India via satellite broadcasting in 1975 and 1976, covering more than 2600 villages in six states of India and territories. Over the years India built communication satellites indigenously to meet the communication requirements of India. This has further lead to launch of an exclusive satellite from ISRO for educational purposes i.e. EDUSAT in 2004 through which rich audio-video content is transmitted / received, recreating virtual classes through interactivity. Indian Institute of Remote Sensing (IIRS) established in 1966, a premier institute in south East Asia in disseminating Remote Sensing (RS) and Geographical Information System (GIS), mainly focusing on contact based programs. But expanded the scope with satellite based Distance Learning Programs for Universities, utilizing the dedicated communication satellite i.e. EDUSAT in 2007. IIRS conducted successfully eight Distance Learning Programs in the last five years and training more than 6000 students mainly at postgraduate level from more than 60 universities /Institutions spread across India. IIRS obtained feedback and improved the programs on the continuous basis. Expanded the scope of IIRS outreach program to train user departments tailor made in any of the applications of Remote Sensing and Geoinformation, capacity
Two above-ground forest biomass estimation techniques were evaluated for the United States Territory of Puerto Rico using predictor variables acquired from satellite based remotely sensed data and ground data from the U.S. Department of Agriculture Forest Inventory Analysis (FIA)...
Zhang Wanliang; Liu Dechang
This paper has discussed the latest development of satellite remote sensing in sensor resolutions, satellite motion models, load forms, data processing and its application. The authors consider that sensor resolutions of satellite remote sensing have increased largely. Valid integration of multisensors is a new idea and technology of satellite remote sensing in the 21st century, and post-remote sensing application technology is the important part of deeply applying remote sensing information and has great practical significance. (authors)
Gogoi, Mukunda M.; Babu, S. Suresh
In view of the increasing anthropogenic presence and influence of aerosols in the northern polar regions, long-term continuous measurements of aerosol optical parameters have been investigated over the Svalbard region of Norwegian Arctic (Ny-Ålesund, 79°N, 12°E, 8 m ASL). This study has shown a consistent enhancement in the aerosol scattering and absorption coefficients during spring. The relative dominance of absorbing aerosols is more near the surface (lower single scattering albedo), compared to that at the higher altitude. This is indicative of the presence of local anthropogenic activities. In addition, long-range transported biomass burning aerosols (inferred from the spectral variation of absorption coefficient) also contribute significantly to the higher aerosol absorption in the Arctic spring. Aerosol optical depth (AOD) estimates from ground based Microtop sun-photometer measurements reveals that the columnar abundance of aerosols reaches the peak during spring season. Comparison of AODs between ground based and satellite remote sensing indicates that deep blue algorithm of Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals over Arctic snow surfaces overestimate the columnar AOD.
Hansell, Richard Allen, Jr.
The radiative effects of dust aerosol on our climate system have yet to be fully understood and remain a topic of contemporary research. To investigate these effects, detection/retrieval methods for dust events over major dust outbreak and transport areas have been developed using satellite and ground-based approaches. To this end, both the shortwave and longwave surface radiative forcing of dust aerosol were investigated. The ground-based remote sensing approach uses the Atmospheric Emitted Radiance Interferometer brightness temperature spectra to detect mineral dust events and to retrieve their properties. Taking advantage of the high spectral resolution of the AERI instrument, absorptive differences in prescribed thermal IR window sub-band channels were exploited to differentiate dust from cirrus clouds. AERI data collected during the UAE2 at Al-Ain UAE was employed for dust retrieval. Assuming a specified dust composition model a priori and using the light scattering programs of T-matrix and the finite difference time domain methods for oblate spheroids and hexagonal plates, respectively, dust optical depths have been retrieved and compared to those inferred from a collocated and coincident AERONET sun-photometer dataset. The retrieved optical depths were then used to determine the dust longwave surface forcing during the UAE2. Likewise, dust shortwave surface forcing is investigated employing a differential technique from previous field studies. The satellite-based approach uses MODIS thermal infrared brightness temperature window data for the simultaneous detection/separation of mineral dust and cirrus clouds. Based on the spectral variability of dust emissivity at the 3.75, 8.6, 11 and 12 mum wavelengths, the D*-parameter, BTD-slope and BTD3-11 tests are combined to identify dust and cirrus. MODIS data for the three dust-laden scenes have been analyzed to demonstrate the effectiveness of this detection/separation method. Detected daytime dust and cloud
Udelhoven, Thomas; Schlerf, Martin; Segl, Karl; Mallick, Kaniska; Bossung, Christian; Retzlaff, Rebecca; Rock, Gilles; Fischer, Peter; Müller, Andreas; Storch, Tobias; Eisele, Andreas; Weise, Dennis; Hupfer, Werner; Knigge, Thiemo
This paper describes the concept of the hyperspectral Earth-observing thermal infrared (TIR) satellite mission HiTeSEM (High-resolution Temperature and Spectral Emissivity Mapping). The scientific goal is to measure specific key variables from the biosphere, hydrosphere, pedosphere, and geosphere related to two global problems of significant societal relevance: food security and human health. The key variables comprise land and sea surface radiation temperature and emissivity, surface moisture, thermal inertia, evapotranspiration, soil minerals and grain size components, soil organic carbon, plant physiological variables, and heat fluxes. The retrieval of this information requires a TIR imaging system with adequate spatial and spectral resolutions and with day-night following observation capability. Another challenge is the monitoring of temporally high dynamic features like energy fluxes, which require adequate revisit time. The suggested solution is a sensor pointing concept to allow high revisit times for selected target regions (1-5 days at off-nadir). At the same time, global observations in the nadir direction are guaranteed with a lower temporal repeat cycle (>1 month). To account for the demand of a high spatial resolution for complex targets, it is suggested to combine in one optic (1) a hyperspectral TIR system with ~75 bands at 7.2-12.5 µm (instrument NEDT 0.05 K-0.1 K) and a ground sampling distance (GSD) of 60 m, and (2) a panchromatic high-resolution TIR-imager with two channels (8.0-10.25 µm and 10.25-12.5 µm) and a GSD of 20 m. The identified science case requires a good correlation of the instrument orbit with Sentinel-2 (maximum delay of 1-3 days) to combine data from the visible and near infrared (VNIR), the shortwave infrared (SWIR) and TIR spectral regions and to refine parameter retrieval.
Full Text Available This paper describes the concept of the hyperspectral Earth-observing thermal infrared (TIR satellite mission HiTeSEM (High-resolution Temperature and Spectral Emissivity Mapping. The scientific goal is to measure specific key variables from the biosphere, hydrosphere, pedosphere, and geosphere related to two global problems of significant societal relevance: food security and human health. The key variables comprise land and sea surface radiation temperature and emissivity, surface moisture, thermal inertia, evapotranspiration, soil minerals and grain size components, soil organic carbon, plant physiological variables, and heat fluxes. The retrieval of this information requires a TIR imaging system with adequate spatial and spectral resolutions and with day-night following observation capability. Another challenge is the monitoring of temporally high dynamic features like energy fluxes, which require adequate revisit time. The suggested solution is a sensor pointing concept to allow high revisit times for selected target regions (1–5 days at off-nadir. At the same time, global observations in the nadir direction are guaranteed with a lower temporal repeat cycle (>1 month. To account for the demand of a high spatial resolution for complex targets, it is suggested to combine in one optic (1 a hyperspectral TIR system with ~75 bands at 7.2–12.5 µm (instrument NEDT 0.05 K–0.1 K and a ground sampling distance (GSD of 60 m, and (2 a panchromatic high-resolution TIR-imager with two channels (8.0–10.25 µm and 10.25–12.5 µm and a GSD of 20 m. The identified science case requires a good correlation of the instrument orbit with Sentinel-2 (maximum delay of 1–3 days to combine data from the visible and near infrared (VNIR, the shortwave infrared (SWIR and TIR spectral regions and to refine parameter retrieval.
Karale, Yogita; Mohite, Jayant; Jagyasi, Bhushan
In this paper, we envision the use of satellite images coupled with GIS to obtain location specific crop type information in order to disseminate crop specific advises to the farmers. In our ongoing mKRISHI R project, the accurate information about the field level crop type and acreage will help in the agro-advisory services and supply chain planning and management. The key contribution of this paper is the field level crop classification using multi temporal images of Landsat-8 acquired during November 2013 to April 2014. The study area chosen is Vani, Maharashtra, India, from where the field level ground truth information for various crops such as grape, wheat, onion, soybean, tomato, along with fodder and fallow fields has been collected using the mobile application. The ground truth information includes crop type, crop stage and GPS location for 104 farms in the study area with approximate area of 42 hectares. The seven multi-temporal images of the Landsat-8 were used to compute the vegetation indices namely: Normalized Difference Vegetation Index (NDVI), Simple Ratio (SR) and Difference Vegetation Index (DVI) for the study area. The vegetation indices values of the pixels within a field were then averaged to obtain the field level vegetation indices. For each crop, binary classification has been carried out using the feed forward neural network operating on the field level vegetation indices. The classification accuracy for the individual crop was in the range of 74.5% to 97.5% and the overall classification accuracy was found to be 88.49%.
P. L. N. Raju
Full Text Available One of the prime activities of Indian Space Research Organisation's (ISRO Space Program is providing satellite communication services, viz., television broadcasting, mobile communication, cyclone disaster warning and rescue operations etc. so as to improve their economic conditions, disseminate technical / scientific knowledge to improve the agriculture production and education for rural people of India. ISRO, along with National Aeronautical and Space Administration (NASA conducted experimental satellite communication project i.e. Satellite Instructional Television Experiment (SITE using NASA’s Advanced Telecommunication Satellite (i.e. ATS 6 with an objective to educate poor people of India via satellite broadcasting in 1975 and 1976, covering more than 2600 villages in six states of India and territories. Over the years India built communication satellites indigenously to meet the communication requirements of India. This has further lead to launch of an exclusive satellite from ISRO for educational purposes i.e. EDUSAT in 2004 through which rich audio-video content is transmitted / received, recreating virtual classes through interactivity. Indian Institute of Remote Sensing (IIRS established in 1966, a premier institute in south East Asia in disseminating Remote Sensing (RS and Geographical Information System (GIS, mainly focusing on contact based programs. But expanded the scope with satellite based Distance Learning Programs for Universities, utilizing the dedicated communication satellite i.e. EDUSAT in 2007. IIRS conducted successfully eight Distance Learning Programs in the last five years and training more than 6000 students mainly at postgraduate level from more than 60 universities /Institutions spread across India. IIRS obtained feedback and improved the programs on the continuous basis. Expanded the scope of IIRS outreach program to train user departments tailor made in any of the applications of Remote Sensing and
Tariq, Salman; Zia, ul-Haq; Ali, Muhammad
Due to increase in population and economic development, the mega-cities are facing increased haze events which are causing important effects on the regional environment and climate. In order to understand these effects, we require an in-depth knowledge of optical and physical properties of aerosols in intense haze conditions. In this paper an effort has been made to analyze the microphysical and optical properties of aerosols during intense haze event over mega-city of Lahore by using remote sensing data obtained from satellites (Terra/Aqua Moderate-resolution Imaging Spectroradiometer (MODIS) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)) and ground based instrument (AErosol RObotic NETwork (AERONET)) during 6-14 October 2013. The instantaneous highest value of Aerosol Optical Depth (AOD) is observed to be 3.70 on 9 October 2013 followed by 3.12 on 8 October 2013. The primary cause of such high values is large scale crop residue burning and urban-industrial emissions in the study region. AERONET observations show daily mean AOD of 2.36 which is eight times higher than the observed values on normal day. The observed fine mode volume concentration is more than 1.5 times greater than the coarse mode volume concentration on the high aerosol burden day. We also find high values (~0.95) of Single Scattering Albedo (SSA) on 9 October 2013. Scatter-plot between AOD (500 nm) and Angstrom exponent (440-870 nm) reveals that biomass burning/urban-industrial aerosols are the dominant aerosol type on the heavy aerosol loading day over Lahore. MODIS fire activity image suggests that the areas in the southeast of Lahore across the border with India are dominated by biomass burning activities. A Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model backward trajectory showed that the winds at 1000 m above the ground are responsible for transport from southeast region of biomass burning to Lahore. CALIPSO derived sub-types of
Faundeen, John L.; Longhenry, Ryan
The National Satellite Land Remote Sensing Data Archive is managed on behalf of the Secretary of the Interior by the U.S. Geological Survey’s Earth Resources Observation and Science Center. The Land Remote Sensing Policy Act of 1992 (51 U.S.C. §601) directed the U.S. Department of the Interior to establish a permanent global archive consisting of imagery over land areas obtained from satellites orbiting the Earth. The law also directed the U.S. Department of the Interior, delegated to the U.S. Geological Survey, to ensure proper storage and preservation of imagery, and timely access for all parties. Since 2008, these images have been available at no cost to the user.
Raju, P. L. N.; Gupta, P. K.; Roy, P. S.
Geoinformatics is a highly specialized discipline that deals with Remote Sensing, Geographical Information System (GIS), Global Positioning System (GPS) and field surveys for assessing, quantification, development and management of resources, planning and infrastructure development, utility services etc. Indian Institute of Remote Sensing (IIRS), a premier institute and one of its kinds has played a key role for capacity Building in this specialized area since its inception in 1966. Realizing the large demand, IIRS has started outreach program in basics of Remote Sensing, GIS and GPS for universities and institutions. EDUSAT (Educational Satellite) is the communication satellite built and launched by ISRO in 2004 exclusively for serving the educational sector to meet the demand for an interactive satellite based distance education system for the country. IIRS has used EDUSAT (shifted to INSAT 4 CR recently due to termination of services from EDUSAT) for its distance learning program to impart basic training in Remote Sensing, GIS and GPS, catering to the universities spread across India. The EDUSAT based training is following similar to e-learning method but has advantage of live interaction sessions between teacher and the students when the lecture is delivered using EDUSAT satellite communication. Because of its good quality reception the interactions are not constrained due to bandwidth problems of Internet. National Natural Resource Management System, Department of Space, Government of India, under Standing Committee in Training and Technology funded this unique program to conduct the basic training in Geoinformatics. IIRS conducts 6 weeks basic training course on "Remote Sensing, GIS and GPS" regularly since the year 2007. The course duration is spread over the period of 3 months beginning with the start of the academic year (1st semester) i.e., July to December every year, for university students. IIRS has utilized EDUSAT satellite for conducting 4 six weeks
Tao Zhangsheng; Zhao Yingjun
Based on the application status of satellite remote sensing technology to nuclear safeguards, advantage of satellite remote sensing technology is analyzed, main types of satellite image used in nuclear safeguards are elaborated and the main application of satellite images is regarded to detect, verify and monitor nuclear activities; verify additional protocol declaration and design information, support performing complementary access inspections; investigate alleged undeclared activities based on open source or the third party information. Application examples of satellite image in nuclear safeguards to analyze nuclear facilities by other countries, the ability of remote sensing technology in nuclear safeguards is discussed. (authors)
Valderrama-Landeros, L; Flores-de-Santiago, F; Kovacs, J M; Flores-Verdugo, F
Optimizing the classification accuracy of a mangrove forest is of utmost importance for conservation practitioners. Mangrove forest mapping using satellite-based remote sensing techniques is by far the most common method of classification currently used given the logistical difficulties of field endeavors in these forested wetlands. However, there is now an abundance of options from which to choose in regards to satellite sensors, which has led to substantially different estimations of mangrove forest location and extent with particular concern for degraded systems. The objective of this study was to assess the accuracy of mangrove forest classification using different remotely sensed data sources (i.e., Landsat-8, SPOT-5, Sentinel-2, and WorldView-2) for a system located along the Pacific coast of Mexico. Specifically, we examined a stressed semiarid mangrove forest which offers a variety of conditions such as dead areas, degraded stands, healthy mangroves, and very dense mangrove island formations. The results indicated that Landsat-8 (30 m per pixel) had the lowest overall accuracy at 64% and that WorldView-2 (1.6 m per pixel) had the highest at 93%. Moreover, the SPOT-5 and the Sentinel-2 classifications (10 m per pixel) were very similar having accuracies of 75 and 78%, respectively. In comparison to WorldView-2, the other sensors overestimated the extent of Laguncularia racemosa and underestimated the extent of Rhizophora mangle. When considering such type of sensors, the higher spatial resolution can be particularly important in mapping small mangrove islands that often occur in degraded mangrove systems.
Mapping water use and drought with satellite remote sensing. Martha C. Anderson, Bill Kustas, Feng Gao, Kate Semmens. USDA-Agricultural Research Service Hydrology and Remote Sensing Laboratory, Beltsville, MD. Chris Hain NOAA-NESDIS
Cheng, Yufeng; Jin, Shuying; Wang, Mi; Zhu, Ying; Dong, Zhipeng
The linear array push broom imaging mode is widely used for high resolution optical satellites (HROS). Using double-cameras attached by a high-rigidity support along with push broom imaging is one method to enlarge the field of view while ensuring high resolution. High accuracy image mosaicking is the key factor of the geometrical quality of complete stitched satellite imagery. This paper proposes a high accuracy image mosaicking approach based on the big virtual camera (BVC) in the double-camera system on the GaoFen2 optical remote sensing satellite (GF2). A big virtual camera can be built according to the rigorous imaging model of a single camera; then, each single image strip obtained by each TDI-CCD detector can be re-projected to the virtual detector of the big virtual camera coordinate system using forward-projection and backward-projection to obtain the corresponding single virtual image. After an on-orbit calibration and relative orientation, the complete final virtual image can be obtained by stitching the single virtual images together based on their coordinate information on the big virtual detector image plane. The paper subtly uses the concept of the big virtual camera to obtain a stitched image and the corresponding high accuracy rational function model (RFM) for concurrent post processing. Experiments verified that the proposed method can achieve seamless mosaicking while maintaining the geometric accuracy.
Tramutoli, V; Di Bello, G [Potenza Univ., Potenza (Italy). Dipt. di Ingegneria e Fisica dell' Ambiente; Pergola, N; Piscitelli, S [Consiglio Nazionale delle Ricerche, Istituto di Metodologie Avanzate di Analisi Ambientale, Potenza (Italy)
Several satellite techniques have been recently proposed to remotely map seismically active zones and to monitor geophysical phenomena possibly associated with earthquakes. Even if questionable in terms of their effective applicability, all these techniques highlight as the major problem, still to be overcome, the high number of natural factors (independent of any seismic activity) whose variable contributions to the investigated signal can be so high as to completely mask (or simulate) the space-time anomaly possibly associated to the seismic event under study. A robust approach (RAT) has recently been proposed (and successfully applied in the field of the monitoring of the major environmental risks) which, better than other methods, seems suitable for recognising space-time anomalies in the satellite observation field also in the presence of highly variable contributions from atmospheric (transmittance), surface (emissivity and morphology) and observational (time/season, but also solar and satellite zenithal angles) conditions. This work presents the first preliminary results, based on several years of NOA A/AVHRR observations, regarding its extension to satellite monitoring of thermal anomalies possibly associated to seismically active areas of Southern Italy. The main merits of this approach are its robustness against the possibility of false events detection (specially important for this kind of applications) as well as its intrinsic exportability not only to different geographic areas but also to different satellite instrumental packages.
Full Text Available Several satellite techniques have been recently proposed to remotely map seismically active zones and to monitor geophysical phenomena possibly associated with earthquakes. Even if questionable in terms of their effective applicability, all these techniques highlight as the major problem, still to be overcome, the high number of natural factors (independent of any seismic activity whose variable contributions to the investigated signal can be so high as to completely mask (or simulate the space-time anomaly possibly associated to the seismic event under study. A robust approach (RAT has recently been proposed (and successfully applied in the field of the monitoring of the major environmental risks which, better than other methods, seems suitable for recognising space-time anomalies in the satellite observational field also in the presence of highly variable contributions from atmospheric (transmittance, surface (emissivity and morphology and observational (time/season, but also solar and satellite zenithal angles conditions.This work presents the first preliminary results, based on several years of NOAA/AVHRR observations, regarding its extension to satellite monitoring of thermal anomalies possibly associated to seismically active areas of Southern Italy. The main merits of this approach are its robustness against the possibility of false events detection (specially important for this kind of applications as well as its intrinsic exportability not only to different geographic areas but also to different satellite instrumental packages.
Full Text Available In arid zones, the shortage of bee forage is critical and usually compels beekeepers to move their colonies in search of better forages. Identifying and mapping the spatiotemporal distribution of the bee forages over given area is important for better management of bee colonies. In this study honey bee plants in the target areas were inventoried following, ground inventory work supported with GIS applications. The study was conducted on 85 large plots of 50 × 50 m each. At each plot, data on species name, height, base diameter, crown height, crown diameter has been taken for each plant with their respective geographical positions. The data were stored, and processed using Trimble GPS supported with ArcGIS10 software program. The data were used to estimate the relative frequency, density, abundance and species diversity, species important value index and apicultural value of the species. In addition, Remotely Sensed Satellite Image of the area was obtained and processed using Hopfield Artificial Neural Network techniques. During the study, 182 species from 49 plant families were identified as bee forages of the target area. From the total number of species; shrubs, herbs and trees were accounting for 61%, 27.67%, and 11.53% respectively. Of which Ziziphus spina-christi, Acacia tortilis, Acacia origina, Acacia asak, Lavandula dentata, and Hypoestes forskaolii were the major nectar source plants of the area in their degree of importance. The average vegetation cover values of the study areas were low (<30% with low Shannon’s species diversity indices (H′ of 0.5–1.52 for different sites. Based on the eco-climatological factors and the variations in their flowering period, these major bee forage species were found to form eight distinct spatiotemporal categories which allow beekeepers to migrate their colonies to exploit the resources at different seasons and place. The Remote Sensed Satellite Image analysis confirmed the spatial
DTC) algorithm for classification of remotely sensed satellite data (Landsat TM) using open source support. The decision tree is constructed by recursively partitioning the spectral distribution of the training dataset using WEKA, open source ...
Kanniah, Kasturi Devi; Lim, Hui Qi; Kaskaoutis, Dimitris G.; Cracknell, Arthur P.
Spatio-temporal variation and trends in atmospheric aerosols as well as their impact on solar radiation and clouds are crucial for regional and global climate change assessment. These topics are not so well-documented over Malaysia, the fact that it receives considerable amounts of pollutants from both local and trans-boundary sources. The present study aims to analyse the spatio-temporal evolution and decadal trend of Aerosol Optical Depth (AOD) from Terra and Aqua MODIS sensors, to identify different types and origin of aerosols and explore the link between aerosols and solar radiation. AOD and fine-mode fraction (FMF) products from MODIS, AOD and Ångström Exponent (AE) values from AERONET stations along with ground-based PM10 measurements and solar radiation recordings at selected sites in Peninsular Malaysia are used for this scope. The MODIS AODs exhibit a wide spatio-temporal variation over Peninsular Malaysia, while Aqua AOD is consistently lower than that from Terra. The AOD shows a neutral-to-declining trend during the 2000s (Terra satellite), while that from Aqua exhibits an increasing trend (~ 0.01 per year). AERONET AODs exhibit either insignificant diurnal variation or higher values during the afternoon, while their short-term availability does not allow for a trend analysis. Moreover, the PM10 concentrations exhibit a general increasing trend over the examined locations. The sources and destination of aerosols are identified via the HYSPLIT trajectory model, revealing that aerosols during the dry season (June to September) are mainly originated from the west and southwest (Sumatra, Indonesia), while in the wet season (November to March) they are mostly associated with the northeast monsoon winds from the southern China Sea. Different aerosol types are identified via the relationship of AOD with FMF, revealing that the urban and biomass-burning aerosols are the most abundant over the region contributing to a significant reduction (~- 0.21 MJ m- 2) of
With the advent of Google Earth, Google Maps, and Microsoft Bing Maps, high resolution satellite imagery are becoming more easily accessible than ever. It have been the case that the college students may already have wealth experiences with the high resolution satellite imagery by using these software and web services prior to any formal remote sensing education. It is obvious that the remote sensing education should be adjusted to the fact that the audience are already the customers of remote sensing products (through the use of the above mentioned services). This paper reports the use of openly available satellite imagery in an introductory-level remote sensing course in the Department of Geomatics of National Cheng Kung University as a term project. From the experience learned from the fall of 2009 and 2010, it shows that this term project has effectively aroused the students' enthusiastic toward Remote Sensing.
Hugue, F.; Lapointe, M.; Eaton, B. C.; Lepoutre, A.
We illustrate an approach to quantify patterns in hydraulic habitat composition and local heterogeneity applicable at low cost over very large river extents, with selectable reach window scales. Ongoing developments in remote sensing and geographical information science massively improve efficiencies in analyzing earth surface features. With the development of new satellite sensors and drone platforms and with the lowered cost of high resolution multispectral imagery, fluvial geomorphology is experiencing a revolution in mapping streams at high resolution. Exploiting the power of aerial or satellite imagery is particularly useful in a riverscape research framework (Fausch et al., 2002), where high resolution sampling of fluvial features and very large coverage extents are needed. This study presents a satellite remote sensing method that requires very limited field calibration data to estimate over various scales ranging from 1 m to many tens or river kilometers (i) spatial composition metrics for key hydraulic mesohabitat types and (ii) reach-scale wetted habitat heterogeneity indices such as the hydromorphological index of diversity (HMID). When the purpose is hydraulic habitat characterization applied over long river networks, the proposed method (although less accurate) is much less computationally expensive and less data demanding than two dimensional computational fluid dynamics (CFD). Here, we illustrate the tools based on a Worldview 2 satellite image of the Kiamika River, near Mont Laurier, Quebec, Canada, specifically over a 17-km river reach below the Kiamika dam. In the first step, a high resolution water depth (D) map is produced from a spectral band ratio (calculated from the multispectral image), calibrated with limited field measurements. Next, based only on known river discharge and estimated cross section depths at time of image capture, empirical-based pseudo-2D hydraulic rules are used to rapidly generate a two-dimensional map of flow velocity
W. Z. Hou
Full Text Available This paper evaluates the information content for the retrieval of key aerosol microphysical and surface properties for multispectral single-viewing satellite polarimetric measurements cantered at 410, 443, 555, 670, 865, 1610 and 2250 nm over bright land. To conduct the information content analysis, the synthetic data are simulated by the Unified Linearized Vector Radiative Transfer Model (UNLVTM with the intensity and polarization together over bare soil surface for various scenarios. Following the optimal estimation theory, a principal component analysis method is employed to reconstruct the multispectral surface reflectance from 410 nm to 2250 nm, and then integrated with a linear one-parametric BPDF model to represent the contribution of polarized surface reflectance, thus further to decouple the surface-atmosphere contribution from the TOA measurements. Focusing on two different aerosol models with the aerosol optical depth equal to 0.8 at 550 nm, the total DFS and DFS component of each retrieval aerosol and surface parameter are analysed. The DFS results show that the key aerosol microphysical properties, such as the fine- and coarse-mode columnar volume concentration, the effective radius and the real part of complex refractive index at 550 nm, could be well retrieved with the surface parameters simultaneously over bare soil surface type. The findings of this study can provide the guidance to the inversion algorithm development over bright surface land by taking full use of the single-viewing satellite polarimetric measurements.
Hou, W. Z.; Li, Z. Q.; Zheng, F. X.; Qie, L. L.
This paper evaluates the information content for the retrieval of key aerosol microphysical and surface properties for multispectral single-viewing satellite polarimetric measurements cantered at 410, 443, 555, 670, 865, 1610 and 2250 nm over bright land. To conduct the information content analysis, the synthetic data are simulated by the Unified Linearized Vector Radiative Transfer Model (UNLVTM) with the intensity and polarization together over bare soil surface for various scenarios. Following the optimal estimation theory, a principal component analysis method is employed to reconstruct the multispectral surface reflectance from 410 nm to 2250 nm, and then integrated with a linear one-parametric BPDF model to represent the contribution of polarized surface reflectance, thus further to decouple the surface-atmosphere contribution from the TOA measurements. Focusing on two different aerosol models with the aerosol optical depth equal to 0.8 at 550 nm, the total DFS and DFS component of each retrieval aerosol and surface parameter are analysed. The DFS results show that the key aerosol microphysical properties, such as the fine- and coarse-mode columnar volume concentration, the effective radius and the real part of complex refractive index at 550 nm, could be well retrieved with the surface parameters simultaneously over bare soil surface type. The findings of this study can provide the guidance to the inversion algorithm development over bright surface land by taking full use of the single-viewing satellite polarimetric measurements.
Adgaba, Nuru; Alghamdi, Ahmed; Sammoud, Rachid; Shenkute, Awraris; Tadesse, Yilma; Ansari, Mahammad J; Sharma, Deepak; Hepburn, Colleen
In arid zones, the shortage of bee forage is critical and usually compels beekeepers to move their colonies in search of better forages. Identifying and mapping the spatiotemporal distribution of the bee forages over given area is important for better management of bee colonies. In this study honey bee plants in the target areas were inventoried following, ground inventory work supported with GIS applications. The study was conducted on 85 large plots of 50 × 50 m each. At each plot, data on species name, height, base diameter, crown height, crown diameter has been taken for each plant with their respective geographical positions. The data were stored, and processed using Trimble GPS supported with ArcGIS10 software program. The data were used to estimate the relative frequency, density, abundance and species diversity, species important value index and apicultural value of the species. In addition, Remotely Sensed Satellite Image of the area was obtained and processed using Hopfield Artificial Neural Network techniques. During the study, 182 species from 49 plant families were identified as bee forages of the target area. From the total number of species; shrubs, herbs and trees were accounting for 61%, 27.67%, and 11.53% respectively. Of which Ziziphus spina-christi , Acacia tortilis , Acacia origina , Acacia asak , Lavandula dentata , and Hypoestes forskaolii were the major nectar source plants of the area in their degree of importance. The average vegetation cover values of the study areas were low (GIS and satellite image processing techniques could be an important tool for characterizing and mapping the available bee forage resources leading to their efficient and sustainable utilization.
Doyle, S. E.
International cooperation in the U.S. Space Program is discussed and related to the NASA program for remote sensing of the earth. Satellite remote sensing techniques are considered along with the selection of the best sensors and wavelength bands. The technology of remote sensing satellites is considered with emphasis on the Landsat system configuration. Future aspects of remote sensing satellites are considered.
Remote sensing technology has the potential to enhance the engagement of communities and managers in the implementation and performance of best management practices. This presentation will use examples from U.S. numeric criteria development and state water quality monitoring prog...
A. H. Ahrari
Full Text Available Multimodal remote sensing approach is based on merging different data in different portions of electromagnetic radiation that improves the accuracy in satellite image processing and interpretations. Remote Sensing Visible and thermal infrared bands independently contain valuable spatial and spectral information. Visible bands make enough information spatially and thermal makes more different radiometric and spectral information than visible. However low spatial resolution is the most important limitation in thermal infrared bands. Using satellite image fusion, it is possible to merge them as a single thermal image that contains high spectral and spatial information at the same time. The aim of this study is a performance assessment of thermal and visible image fusion quantitatively and qualitatively with wavelet transform and different filters. In this research, wavelet algorithm (Haar and different decomposition filters (mean.linear,ma,min and rand for thermal and panchromatic bands of Landast8 Satellite were applied as shortwave and longwave fusion method . Finally, quality assessment has been done with quantitative and qualitative approaches. Quantitative parameters such as Entropy, Standard Deviation, Cross Correlation, Q Factor and Mutual Information were used. For thermal and visible image fusion accuracy assessment, all parameters (quantitative and qualitative must be analysed with respect to each other. Among all relevant statistical factors, correlation has the most meaningful result and similarity to the qualitative assessment. Results showed that mean and linear filters make better fused images against the other filters in Haar algorithm. Linear and mean filters have same performance and there is not any difference between their qualitative and quantitative results.
Full Text Available Under the background of the trouble shooting requirements of FENGYUN-3 (FY-3 meteorological satellites data acquisition in domestic and oversea ground stations, a remote fault reasoning diagnosis system is developed by Java 1.6 in eclipse 3.6 platform. The general framework is analyzed, the workflow is introduced. Based on the system, it can realize the remote and centralized monitoring of equipment running status in ground stations，triggering automatic fault diagnosis and rule based fault reasoning by parsing the equipment quality logs, generating trouble tickets and importing expert experience database, providing text and graphics query methods. Through the practical verification, the system can assist knowledge engineers in remote precise and rapid fault location with friendly graphical user interface, boost the fault diagnosis efficiency, enhance the remote monitoring ability of integrity operating control system. The system has a certain practical significance to improve reliability of FY-3 meteorological satellites data acquisition.
Full Text Available Super low altitude remote sensing satellites maintain lower flight altitudes by means of ion propulsion in order to improve image resolution and positioning accuracy. The use of engineering data in design for achieving image positioning accuracy is discussed in this paper based on the principles of the photogrammetry theory. The exact line-of-sight rebuilding of each detection element and this direction precisely intersecting with the Earth's elliptical when the camera on the satellite is imaging are both ensured by the combined design of key parameters. These parameters include: orbit determination accuracy, attitude determination accuracy, camera exposure time, accurately synchronizing the reception of ephemeris with attitude data, geometric calibration and precise orbit verification. Precise simulation calculations show that image positioning accuracy of super low altitude remote sensing satellites is not obviously improved. The attitude determination error of a satellite still restricts its positioning accuracy.
Dean, K.; Servilla, M.; Roach, A.; Foster, B.; Engle, K.
Satellite monitoring of remote volcanoes is greatly benefitting the Alaska Volcano Observatory (AVO), and last year's eruption of the Okmok Volcano in the Aleutian Islands is a good case in point. The facility was able to issue and refine warnings of the eruption and related activity quickly, something that could not have been done using conventional seismic surveillance techniques, since seismometers have not been installed at these locations.AVO monitors about 100 active volcanoes in the North Pacific (NOPAC) region, but only a handful are observed by costly and logistically complex conventional means. The region is remote and vast, about 5000 × 2500 km, extending from Alaska west to the Kamchatka Peninsula in Russia (Figure 1). Warnings are transmitted to local communities and airlines that might be endangered by eruptions. More than 70,000 passenger and cargo flights fly over the region annually, and airborne volcanic ash is a threat to them. Many remote eruptions have been detected shortly after the initial magmatic activity using satellite data, and eruption clouds have been tracked across air traffic routes. Within minutes after eruptions are detected, information is relayed to government agencies, private companies, and the general public using telephone, fax, and e-mail. Monitoring of volcanoes using satellite image data involves direct reception, real-time monitoring, and data analysis. Two satellite data receiving stations, located at the Geophysical Institute, University of Alaska Fairbanks (UAF), are capable of receiving data from the advanced very high resolution radiometer (AVHRR) on National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites and from synthetic aperture radar (SAR) equipped satellites.
Topaz, Jeremy M.; Braun, Ofer; Freiman, Dov
An athermalized objective has been designed for a compact, lightweight push-broom camera which is under development at El-Op Ltd. for use in small remote-sensing satellites. The high performance objective has a fixed focus setting, but maintains focus passively over the full range of temperatures encountered in small satellites. The lens is an F/5.0, 320 mm focal length Tessar type, operating over the range 0.5 - 0.9 micrometers . It has a 16 degree(s) field of view and accommodates various state-of-the-art silicon detector arrays. The design and performance of the objective is described in this paper.
Remote sensing provides an important source of information to characterize soil and crop variability for both within-season and after-season management despite the availability of numerous ground-based soil and crop sensors. Remote sensing applications in precision agriculture have been steadily inc...
Viezzoli, Andrea; Edsen, Anders; Auken, Esben
, satellite remote sensing has been successfully used to identify numerous candidate sites that are most likely to host waste materials. This result was the basis for further monitoring activities based on the use of an helicopter transient electromagnetic (TEM) system, to be carried out at end of April 2009...... and remote sensing methods represents a useful instrument for environmental management....
Full Text Available In the Earth Observation sensor web environment, the rapid, accurate, and unified discovery of diverse remote sensing satellite sensors, and their association to yield an integrated solution for a comprehensive response to specific emergency tasks pose considerable challenges. In this study, we propose a remote sensing satellite sensor object model, based on the object-oriented paradigm and the Open Geospatial Consortium Sensor Model Language. The proposed model comprises a set of sensor resource objects. Each object consists of identification, state of resource attribute, and resource method. We implement the proposed attribute state description by applying it to different remote sensors. A real application, involving the observation of floods at the Yangtze River in China, is undertaken. Results indicate that the sensor inquirer can accurately discover qualified satellite sensors in an accurate and unified manner. By implementing the proposed union operation among the retrieved sensors, the inquirer can further determine how the selected sensors can collaboratively complete a specific observation requirement. Therefore, the proposed model provides a reliable foundation for sharing and integrating multiple remote sensing satellite sensors and their observations.
Toellner, R.L.; Copland, G.V.
An automatic system for positioning a Ku band microwave antenna accurately to within approximately 0.1 degrees to point at a particular satellite located among others having as close as 2 degree angular spacing in geosynchronous earth orbit from a remote location for establishing a Ku band microwave communication link from the remote location via the satellite is described comprising: a Ku band microwave antenna having a gimbal mount adapted to move in at least azimuth and elevation; means for driving the gimbal mount in azimuth and means for driving the gimbal mount in elevation; means for sensing a satellite signal detected by the antenna and for producing an output signal representative of the strength of the satellite signal and a separate output signal indicative of a satellite code or signature; inclinometer means for measuring the actual elevation angle of the elevation gimbal with respect to vertical and for generating an output signal representative thereof; means for measuring the azimuth angle of the azimuth gimbal relative to a fixed reference and for generating an output signal representative thereof; computer means capable of receiving input data comprising the earth latitude and longitude of a remote location and a satellite position and capable of receiving as inputs the strength representative signal; means for pointing the elevation gimbal to a fixed direction and for scanning the azimuth gimbal to a computed direction based on the earth latitude and longitude and the satellite position signals; and wherein the computer means further includes means capable of receiving the input signal indicative of a satellite code or signature and means for comparing the code or signature input signal with a predetermined reference code or signature signal in the memory of the computer means
Sorek-Hammer, M.; Cohen, A.; Levy, Robert C.; Ziv, B.; Broday, D. M.
Considerable progress in satellite remote sensing (SRS) of dust particles has been seen in the last decade. From an environmental health perspective, such an event detection, after linking it to ground particulate matter (PM) concentrations, can proxy acute exposure to respirable particles of certain properties (i.e. size, composition, and toxicity). Being affected considerably by atmospheric dust, previous studies in the Eastern Mediterranean, and in Israel in particular, have focused on mechanistic and synoptic prediction, classification, and characterization of dust events. In particular, a scheme for identifying dust days (DD) in Israel based on ground PM10 (particulate matter of size smaller than 10 nm) measurements has been suggested, which has been validated by compositional analysis. This scheme requires information regarding ground PM10 levels, which is naturally limited in places with sparse ground-monitoring coverage. In such cases, SRS may be an efficient and cost-effective alternative to ground measurements. This work demonstrates a new model for identifying DD and non-DD (NDD) over Israel based on an integration of aerosol products from different satellite platforms (Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI)). Analysis of ground-monitoring data from 2007 to 2008 in southern Israel revealed 67 DD, with more than 88 percent occurring during winter and spring. A Classification and Regression Tree (CART) model that was applied to a database containing ground monitoring (the dependent variable) and SRS aerosol product (the independent variables) records revealed an optimal set of binary variables for the identification of DD. These variables are combinations of the following primary variables: the calendar month, ground-level relative humidity (RH), the aerosol optical depth (AOD) from MODIS, and the aerosol absorbing index (AAI) from OMI. A logistic regression that uses these variables, coded as binary
Delgreco, F.P.; Eastes, R.W.; Huffman, R.E.
The Polar BEAR satellite carries the Auroral Ionospheric Remote Sensor (AIRS) instrument, which is designed to return four simultaneous images of atmospheric radiation at northern latitudes, has thus far yielded over 5000 images. Polar BEAR was in operation during March, 1987, when the preliminary K(p) reached a value of 9 over a six-hour period; at that time, AIRS was operating at the 1304 A atomic oxygen wavelength and recorded remarkable data, which are here presented. Due to the intense activity, the AIRS data were barely able to register the poleward edge of the aurora. 6 refs
Henderson, Frederick B.; Penfield, Glen T.; Grubbs, Donald K.
The new LANDSAT-4,-5/Thematic Mapper (TM) land observational satellite remote sensing systems are providing dramatically new and important short wave infrared (SWIR) data, which combined with Landsat's Multi-Spectral Scanner (MSS) visible (VIS), very near infrared (VNIR), and thermal infrared (TI) data greatly improves regional geological mapping on a global scale. The TM will significantly improve clay, iron oxide, aluminum, and nickel laterite mapping capabilities over large areas of the world. It will also improve the ability to discriminate vegetation stress and species distribution associated with lateritic environments. Nickel laterites on Gag Island, Indonesia are defined by MSS imagery. Satellite imagery of the Cape Bougainville and the Darling Range, Australia bauxite deposits show the potential use of MSS data for exploration and mining applications. Examples of satellite syn-thetic aperture radar (SAR) for Jamaica document the use of this method for bauxite exploration. Thematic Mapper data will be combined with the French SPOT satellite's high spatial resolution and stereoscopic digital data, and U.S., Japanese, European, and Canadian Synthetic Aperture Radar (SAR) data to assist with logistics, mine development, and environ-mental concerns associated with aluminum and nickel lateritic deposits worldwide.
Omar A. Alcover Firpi
Full Text Available A review of Google Earth Engine for archaeological remote sensing using satellite data. GEE is a freely accessible software option for processing remotely sensed data, part of the larger Google suite of products.
Lin, Shin-Fa; Hwang, Cheinway
Unlike a typical remote sensing satellite that has a global coverage and non-integral orbital revolutions per day, Taiwan's FORMOSAT-2 (FS-2) satellite has a non-global coverage due to the mission requirements of one-day repeat cycle and daily visit around Taiwan. These orbital characteristics result in an integer number of revolutions a day and orbital resonances caused by certain components of the Earth's gravity field. Orbital flight data indicated amplified variations in the amplitudes of FS-2's Keplerian elements. We use twelve years of orbital observations and maneuver data to analyze the cause of the resonances and explain the differences between the simulated (at the pre-launch stage) and real orbits of FS-2. The differences are quantified using orbital perturbation theories that describe secular and long-period orbital evolutions caused by resonances. The resonance-induced orbital rising rate of FS-2 reaches +1.425 m/day, due to the combined (modeled) effect of resonances and atmospheric drags (the relative modeling errors remote sensing mission similar to FS-2, especially in the early mission design and planning phase.
Jackson, J. M.; Munger, J.; Emch, P. G.; Sen, B.; Gu, D.
Satellite to ground communication bandwidth limitations place constraints on current earth remote sensing instruments which limit the spatial and spectral resolution of data transmitted to the ground for processing. Instruments such as VIIRS, CrIS and OMPS on the Soumi-NPP spacecraft must aggregate data both spatially and spectrally in order to fit inside current data rate constraints limiting the optimal use of the as-built sensors. Future planned missions such as HyspIRI, SLI, PACE, and NISAR will have to trade spatial and spectral resolution if increased communication band width is not made available. A number of high-impact, environmental remote sensing disciplines such as hurricane observation, mega-city air quality, wild fire detection and monitoring, and monitoring of coastal oceans would benefit dramatically from enabling the downlinking of sensor data at higher spatial and spectral resolutions. The enabling technologies of multi-Gbps Ka-Band communication, flexible high speed on-board processing, and multi-Terabit SSRs are currently available with high technological maturity enabling high data volume mission requirements to be met with minimal mission constraints while utilizing a limited set of ground sites from NASA's Near Earth Network (NEN) or TDRSS. These enabling technologies will be described in detail with emphasis on benefits to future remote sensing missions currently under consideration by government agencies.
Hong, Yang; Adler, Robert F.; Huffman, George J.
Satellite remote sensing data has significant potential use in analysis of natural hazards such as landslides. Relying on the recent advances in satellite remote sensing and geographic information system (GIS) techniques, this paper aims to map landslide susceptibility over most of the globe using a GIs-based weighted linear combination method. First , six relevant landslide-controlling factors are derived from geospatial remote sensing data and coded into a GIS system. Next, continuous susceptibility values from low to high are assigned to each of the six factors. Second, a continuous scale of a global landslide susceptibility index is derived using GIS weighted linear combination based on each factor's relative significance to the process of landslide occurrence (e.g., slope is the most important factor, soil types and soil texture are also primary-level parameters, while elevation, land cover types, and drainage density are secondary in importance). Finally, the continuous index map is further classified into six susceptibility categories. Results show the hot spots of landslide-prone regions include the Pacific Rim, the Himalayas and South Asia, Rocky Mountains, Appalachian Mountains, Alps, and parts of the Middle East and Africa. India, China, Nepal, Japan, the USA, and Peru are shown to have landslide-prone areas. This first-cut global landslide susceptibility map forms a starting point to provide a global view of landslide risks and may be used in conjunction with satellite-based precipitation information to potentially detect areas with significant landslide potential due to heavy rainfall. 1
Petersen, G. W.; Connors, K. F.; Miller, D. A.; Day, R. L.; Gardner, T. W.
Remote sensing data on desert soils and landscapes, obtained by the Landsat TM, Heat Capacity Mapping Mission (HCMM), Simulated SPOT, and Thermal IR Multispectral Scanner (TIMS) aboard an aircraft, are discussed together with the analytical techniques used in the studies. The TM data for southwestern Nevada were used to discriminate among the alluvial fan deposits with different degrees of desert pavement and varnish, and different vegetation cover. Thermal-IR data acquired from the HCMM satellite were used to map the spatial distribution of diurnal surface temperatures and to estimate mean annual soil temperatures in central Utah. Simulated SPOT data for northwestern New Mexico identified geomorphic features, such as differences in eolian sand cover and fluvial incision, while the TIMS data depicted surface geologic features of the Saline Valley in California.
Wynne, R.H.; Lillesand, T.M.
The paper examines the general hypothesis that large-scale and long-term trends in lake ice formation and breakup, along with changes in the optical properties of lakes, can serve as robust integrated measures of regional and global climate change. Recent variation in the periodicity of lake ice formation and breakup is investigated using the AVHRR aboard the NOAA/TIROS series of polar orbiting satellites. The study area consists of 44 lakes and reservoirs with a surface area of greater than 1000 hectares in Wisconsin. The utility of AVHRR for lake ice detection with high temporal resolution is demonstrated, the relationship between ice phenology and periodicity with lake morphometry for the lakes in the study is elucidated, and remotely sensed measures of ice periodicity are correlated with local and regional temperature trends. 31 refs
Sahai, Arushi; Shao, Andrew; Toloba, Elisa; Guhathakurta, Puragra; Peng, Eric W.; Zhang, Hao
We present a sample of “orphan” globular clusters (GCs) with previously unknown parent galaxies, which we determine to be remote satellites of M87, a massive elliptical galaxy at the center of the Virgo Cluster of Galaxies. Because GCs were formed in the early universe along with their original parent galaxies, which were cannibalized by massive galaxies such as M87, they share similar age and chemical properties. In this study, we first confirm that M87 is the adoptive parent galaxy of our orphan GCs using photometric and spectroscopic data to analyze spatial and velocity distributions. Next, we increase the signal-to-noise ratio of our samples’ spectra through a process known as coaddition. We utilize spectroscopic absorption lines to determine the age and metallicity of our orphan GCs through comparison to stellar population synthesis models, which we then relate to the GCs’ original parent galaxies using a mass-metallicity relation. Our finding that remote GCs of M87 likely developed in galaxies with ~1010 solar masses implies that M87’s outer halo is formed of relatively massive galaxies, serving as important parameters for developing theories about the formation and evolution of massive galaxies.This research was funded in part by NASA/STScI and the National Science Foundation. Most of this work was carried out by high school students working under the auspices of the Science Internship Program at UC Santa Cruz.
Changes to the environment are of critical concern in the world today; consequently, monitoring such changes and assessing their impacts are tasks demanding considerably higher priority. The ecological impacts of the natural global cycles of gases and particulates in the earth's atmosphere are highly influenced by the extent of changes to vegetative canopy characteristics which dictates the need for capability to detect and assess the magnitude of such changes. The primary emphasis of this paper is on the determination of the size and configuration of the sampling unit that maximizes the probability of its intersection with a 'change' area. Assessment of the significance of the 'change' in a given locality is also addressed and relies on a statistical approach that compares the number of elemental units exceeding a reflectance threshold when compared to a previous point in time. Consideration is also given to a technical framework that supports quantifying the magnitude of the 'change' over large areas (i.e., the estimated area changing from forest to agricultural land-use). The latter entails a multistage approach which utilizes satellite-based and other related data sources
Jin, Jiahua; Yan, Xiangbin; Tan, Qiaoqiao; Li, Yijun
With the development of remote sensing technology, remote-sensing satellite has been widely used in many aspects of national construction. Big data with different standards and massive users with different needs, make the satellite data delivery service to be a complex giant system. How to deliver remote-sensing satellite data efficiently and effectively is a big challenge. Based on customer service theory, this paper proposes a hierarchy conceptual model for examining the determinations of remote-sensing satellite data delivery service quality in the Chinese context. Three main dimensions: service expectation, service perception and service environment, and 8 sub-dimensions are included in the model. Large amount of first-hand data on the remote-sensing satellite data delivery service have been obtained through field research, semi-structured questionnaire and focused interview. A positivist case study is conducted to validate and develop the proposed model, as well as to investigate the service status and related influence mechanisms. Findings from the analysis demonstrate the explanatory validity of the model, and provide potentially helpful insights for future practice.
Jin, Jiahua; Yan, Xiangbin; Tan, Qiaoqiao; Li, Yijun
With the development of remote sensing technology, remote-sensing satellite has been widely used in many aspects of national construction. Big data with different standards and massive users with different needs, make the satellite data delivery service to be a complex giant system. How to deliver remote-sensing satellite data efficiently and effectively is a big challenge. Based on customer service theory, this paper proposes a hierarchy conceptual model for examining the determinations of remote-sensing satellite data delivery service quality in the Chinese context. Three main dimensions: service expectation, service perception and service environment, and 8 sub-dimensions are included in the model. Large amount of first-hand data on the remote-sensing satellite data delivery service have been obtained through field research, semi-structured questionnaire and focused interview. A positivist case study is conducted to validate and develop the proposed model, as well as to investigate the service status and related influence mechanisms. Findings from the analysis demonstrate the explanatory validity of the model, and provide potentially helpful insights for future practice
Jonckheere, Inge; Sandoval, Alberto
REDD, which stands for 'Reducing Emissions from Deforestation and Forest Degradation in Developing Countries' - is an effort to create a financial value for the carbon stored in forests, offering incentives for developing countries to reduce emissions from forested lands and invest in low-carbon paths to sustainable development. The UN-REDD Programme, a collaborative partnership between FAO, UNDP and UNEP launched in September 2008, supports countries to develop capacity to REDD and to implement a future REDD mechanism in a post- 2012 climate regime. The programme works at both the national and global scale, through support mechanisms for country-driven REDD strategies and international consensus-building on REDD processes. The UN-REDD Programme gathers technical teams from around the world to develop common approaches, analyses and guidelines on issues such as measurement, reporting and verification (MRV) of carbon emissions and flows, remote sensing, and greenhouse gas inventories. Within the partnership, FAO supports countries on technical issues related to forestry and the development of cost effective and credible MRV processes for emission reductions. While at the international level, it fosters improved guidance on MRV approaches, including consensus on principles and guidelines for MRV and training programmes.It provides guidance on how best to design and implement REDD, to ensure that forests continue to provide multiple benefits for livelihoods and biodiversity to societies while storing carbon at the same time. Other areas of work include national forest assessments and monitoring of in-country policy and institutional change. The outcomes about the role of satellite remote sensing technologies as a tool for monitoring, assessment, reporting and verification of carbon credits and co-benefits under the REDD mechanism are here presented.
Wahballah, Walid A.; Bazan, Taher M.; El-Tohamy, Fawzy; Fathy, Mahmoud
High-resolution remote sensing satellites (HRRSS) that use time delay and integration (TDI) CCDs have the potential to introduce large amounts of image smear. Clocking and velocity mismatch smear are two of the key factors in inducing image smear. Clocking smear is caused by the discrete manner in which the charge is clocked in the TDI-CCDs. The relative motion between the HRRSS and the observed object obliges that the image motion velocity must be strictly synchronized with the velocity of the charge packet transfer (line rate) throughout the integration time. During imaging an object off-nadir, the image motion velocity changes resulting in asynchronization between the image velocity and the CCD's line rate. A Model for estimating the image motion velocity in HRRSS is derived. The influence of this velocity mismatch combined with clocking smear on the modulation transfer function (MTF) is investigated by using Matlab simulation. The analysis is performed for cross-track and along-track imaging with different satellite attitude angles and TDI steps. The results reveal that the velocity mismatch ratio and the number of TDI steps have a serious impact on the smear MTF; a velocity mismatch ratio of 2% degrades the MTFsmear by 32% at Nyquist frequency when the TDI steps change from 32 to 96. In addition, the results show that to achieve the requirement of MTFsmear >= 0.95 , for TDI steps of 16 and 64, the allowable roll angles are 13.7° and 6.85° and the permissible pitch angles are no more than 9.6° and 4.8°, respectively.
Kuo, Jen-Chueh; Ling, Jer
The optical telescope system in remote sensing satellite must be precisely aligned to obtain high quality images during its mission life. In practical, because the telescope mirrors could be misaligned due to launch loads, thermal distortion on supporting structures or hygroscopic distortion effect in some composite materials, the optical telescope system is often equipped with refocussing mechanism to re-align the optical elements while optical element positions are out of range during image acquisition. This paper is to introduce satellite Refocussing mechanism function model design development process and the engineering models. The design concept of the refocussing mechanism can be applied on either cassegrain type telescope or korsch type telescope, and the refocussing mechanism is located at the rear of the secondary mirror in this paper. The purpose to put the refocussing mechanism on the secondary mirror is due to its higher sensitivity on MTF degradation than other optical elements. There are two types of refocussing mechanism model to be introduced: linear type model and rotation type model. For the linear refocussing mechanism function model, the model is composed of ceramic piezoelectric linear step motor, optical rule as well as controller. The secondary mirror is designed to be precisely moved in telescope despace direction through refocussing mechanism. For the rotation refocussing mechanism function model, the model is assembled with two ceramic piezoelectric rotational motors around two orthogonal directions in order to adjust the secondary mirror attitude in tilt angle and yaw angle. From the validation test results, the linear type refocussing mechanism function model can be operated to adjust the secondary mirror position with minimum 500 nm resolution with close loop control. For the rotation type model, the attitude angle of the secondary mirror can be adjusted with the minimum 6 sec of arc resolution and 5°/sec of angle velocity.
Liu, Yang; Li, Feng; Xin, Lei; Fu, Jie; Huang, Puming
Large amount of data is one of the most obvious features in satellite based remote sensing systems, which is also a burden for data processing and transmission. The theory of compressive sensing(CS) has been proposed for almost a decade, and massive experiments show that CS has favorable performance in data compression and recovery, so we apply CS theory to remote sensing images acquisition. In CS, the construction of classical sensing matrix for all sparse signals has to satisfy the Restricted Isometry Property (RIP) strictly, which limits applying CS in practical in image compression. While for remote sensing images, we know some inherent characteristics such as non-negative, smoothness and etc.. Therefore, the goal of this paper is to present a novel measurement matrix that breaks RIP. The new sensing matrix consists of two parts: the standard Nyquist sampling matrix for thumbnails and the conventional CS sampling matrix. Since most of sun-synchronous based satellites fly around the earth 90 minutes and the revisit cycle is also short, lots of previously captured remote sensing images of the same place are available in advance. This drives us to reconstruct remote sensing images through a deep learning approach with those measurements from the new framework. Therefore, we propose a novel deep convolutional neural network (CNN) architecture which takes in undersampsing measurements as input and outputs an intermediate reconstruction image. It is well known that the training procedure to the network costs long time, luckily, the training step can be done only once, which makes the approach attractive for a host of sparse recovery problems.
Burns, J.A.; Matthews, M.S.
The present work is based on a conference: Natural Satellites, Colloquium 77 of the IAU, held at Cornell University from July 5 to 9, 1983. Attention is given to the background and origins of satellites, protosatellite swarms, the tectonics of icy satellites, the physical characteristics of satellite surfaces, and the interactions of planetary magnetospheres with icy satellite surfaces. Other topics include the surface composition of natural satellites, the cratering of planetary satellites, the moon, Io, and Europa. Consideration is also given to Ganymede and Callisto, the satellites of Saturn, small satellites, satellites of Uranus and Neptune, and the Pluto-Charon system
Sogacheva, Larisa; Kolmonen, Pekka; Saponaro, Giulia; Virtanen, Timo; Rodriguez, Edith; Sundström, Anu-Maija; Atlaskina, Ksenia; de Leeuw, Gerrit
Satellite remote sensing provides the spatial distribution of aerosol and cloud properties over a wide area. In our studies large data sets are used for statistical studies on aerosol and cloud interaction in an area over Fennoscandia, the Baltic Sea and adjacent regions over the European mainland. This area spans several regimes with different influences on aerosol cloud interaction such as a the transition from relative clean air over Fennoscandia to more anthropogenically polluted air further south, and the influence maritime air over the Baltic and oceanic air advected from the North Atlantic. Anthropogenic pollution occurs in several parts of the study area, and in particular near densely populated areas and megacities, but also in industrialized areas and areas with dense traffic. The aerosol in such areas is quite different from that produced over the boreal forest and has different effects on air quality and climate. Studies have been made on the effects of aerosols on air quality and on the radiation balance in China. The aim of the study is to study the effect of these different regimes on aerosol-cloud interaction using a large aerosol and cloud data set retrieved with the (Advanced) Along Track Scanning Radiometer (A)ATSR Dual View algorithm (ADV) further developed at Finnish Meteorological Institute and aerosol and cloud data provided by MODIS. Retrieval algorithms for aerosol and clouds have been developed for the (A)ATSR, consisting of a series of instruments of which we use the second and third one: ATSR-2 which flew on the ERS-2 satellite (1995-2003) and AATSR which flew on the ENVISAT satellite (2002-2012) (both from the European Space Agency, ESA). The ADV algorithm provides aerosol data on a global scale with a default resolution of 10x10km2 (L2) and an aggregate product on 1x1 degree (L3). Optional, a 1x1 km2 retrieval products is available over smaller areas for specific studies. Since for the retrieval of AOD no prior knowledge is needed on
Zhang, Wei; Zhang, Gengxin; Dong, Feihong; Xie, Zhidong; Bian, Dongming
This article investigates the capacity problem of an integrated remote wireless sensor and satellite network (IWSSN) in emergency scenarios. We formulate a general model to evaluate the remote sensor and satellite network capacity. Compared to most existing works for ground networks, the proposed model is time varying and space oriented. To capture the characteristics of a practical network, we sift through major capacity-impacting constraints and analyze the influence of these constraints. Specifically, we combine the geometric satellite orbit model and satellite tool kit (STK) engineering software to quantify the trends of the capacity constraints. Our objective in analyzing these trends is to provide insights and design guidelines for optimizing the integrated remote wireless sensor and satellite network schedules. Simulation results validate the theoretical analysis of capacity trends and show the optimization opportunities of the IWSSN. PMID:26593919
Zhang, Wei; Zhang, Gengxin; Dong, Feihong; Xie, Zhidong; Bian, Dongming
This article investigates the capacity problem of an integrated remote wireless sensor and satellite network (IWSSN) in emergency scenarios. We formulate a general model to evaluate the remote sensor and satellite network capacity. Compared to most existing works for ground networks, the proposed model is time varying and space oriented. To capture the characteristics of a practical network, we sift through major capacity-impacting constraints and analyze the influence of these constraints. Specifically, we combine the geometric satellite orbit model and satellite tool kit (STK) engineering software to quantify the trends of the capacity constraints. Our objective in analyzing these trends is to provide insights and design guidelines for optimizing the integrated remote wireless sensor and satellite network schedules. Simulation results validate the theoretical analysis of capacity trends and show the optimization opportunities of the IWSSN.
Giardino, Marco J.; Haley, Bryan S.
Cultural resource management consists of research to identify, evaluate, document and assess cultural resources, planning to assist in decision-making, and stewardship to implement the preservation, protection and interpretation of these decisions and plans. One technique that may be useful in cultural resource management archaeology is remote sensing. It is the acquisition of data and derivative information about objects or materials (targets) located on the Earth's surface or in its atmosphere by using sensor mounted on platforms located at a distance from the targets to make measurements on interactions between the targets and electromagnetic radiation. Included in this definition are systems that acquire imagery by photographic methods and digital multispectral sensors. Data collected by digital multispectral sensors on aircraft and satellite platforms play a prominent role in many earth science applications, including land cover mapping, geology, soil science, agriculture, forestry, water resource management, urban and regional planning, and environmental assessments. Inherent in the analysis of remotely sensed data is the use of computer-based image processing techniques. Geographical information systems (GIS), designed for collecting, managing, and analyzing spatial information, are also useful in the analysis of remotely sensed data. A GIS can be used to integrate diverse types of spatially referenced digital data, including remotely sensed and map data. In archaeology, these tools have been used in various ways to aid in cultural resource projects. For example, they have been used to predict the presence of archaeological resources using modern environmental indicators. Remote sensing techniques have also been used to directly detect the presence of unknown sites based on the impact of past occupation on the Earth's surface. Additionally, remote sensing has been used as a mapping tool aimed at delineating the boundaries of a site or mapping previously
Modeling Surface Energy Fluxes over a Dehesa (Oak Savanna Ecosystem Using a Thermal Based Two Source Energy Balance Model (TSEB II—Integration of Remote Sensing Medium and Low Spatial Resolution Satellite Images
Full Text Available Dehesas are highly valuable agro-forestry ecosystems, widely distributed over Mediterranean-type climate areas, which play a key role in rural development, basing their productivity on a sustainable use of multiple resources (crops, livestock, wildlife, etc.. The information derived from remote sensing based models addressing ecosystem water consumption, at different scales, can be used by institutions and private landowners to support management decisions. In this study, the Two-Source Energy Balance (TSEB model is analyzed over two Spanish dehesa areas integrating multiple satellites (MODIS and Landsat for estimating water use (ET, vegetation ground cover, leaf area and phenology. Instantaneous latent heat (LE values are derived on a regional scale and compared with eddy covariance tower (ECT measurements, yielding accurate results (RMSDMODIS Las Majadas 44 Wm−2, Santa Clotilde RMSDMODIS 47 Wm−2 and RMSDLandsat 64 Wm−2. Daily ET(mm is estimated using daily return interval of MODIS for both study sites and compared with the flux measurements of the ECTs, with RMSD of 1 mm day−1 over Las Majadas and 0.99 mm day−1 over Santa Clotilde. Distributed ET over Andalusian dehesa (15% of the region is successfully mapped using MODIS images, as an approach to monitor the ecosystem status and the vegetation water stress on a regular basis.
Munchak, S. J.; Huffman, G. J.
Of the possible sources of precipitation data, those based on satellites provide the greatest spatial coverage. There is a wide selection of datasets, algorithms, and versions from which to choose, which can be confusing to non-specialists wishing to use the data. The International Precipitation Working Group (IPWG) maintains tables of the major publicly available, long-term, quasi-global precipitation data sets (http://www.isac.cnr.it/ ipwg/data/datasets.html), and this talk briefly reviews the various categories. As examples, NASA provides two sets of quasi-global precipitation data sets: the older Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) and current Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM) mission (IMERG). Both provide near-real-time and post-real-time products that are uniformly gridded in space and time. The TMPA products are 3-hourly 0.25°x0.25° on the latitude band 50°N-S for about 16 years, while the IMERG products are half-hourly 0.1°x0.1° on 60°N-S for over 3 years (with plans to go to 16+ years in Spring 2018). In addition to the precipitation estimates, each data set provides fields of other variables, such as the satellite sensor providing estimates and estimated random error. The discussion concludes with advice about determining suitability for use, the necessity of being clear about product names and versions, and the need for continued support for satellite- and surface-based observation.
Boresjoe Bronge, Laine [SwedPower AB, Stockholm (Sweden)
Land vegetation is a critical component of several biogeochemical cycles that have become the focus of concerted international research effort. Most ecosystem productivity models, carbon budget models, and global models of climate, hydrology and biogeochemistry require vegetation parameters to calculate land surface photosynthesis, evapotranspiration and net primary production. Therefore, accurate estimates of vegetation parameters are increasingly important in the carbon cycle, the energy balance and in environmental impact assessment studies. The possibility of quantitatively estimating vegetation parameters of importance in this context using satellite data has been explored by numerous papers dealing with the subject. This report gives a summary of the present status and applicability of satellite remote sensing for estimating vegetation productivity by using vegetation index for calculating leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FPAR). Some possible approaches for use of satellite data for estimating LAI, FPAR and net primary production (NPP) on a local scale are suggested. Recommendations for continued work in the Forsmark and Oskarshamn investigation areas, where vegetation data and NDVI-images based on satellite data have been produced, are also given.
Boresjoe Bronge, Laine
Land vegetation is a critical component of several biogeochemical cycles that have become the focus of concerted international research effort. Most ecosystem productivity models, carbon budget models, and global models of climate, hydrology and biogeochemistry require vegetation parameters to calculate land surface photosynthesis, evapotranspiration and net primary production. Therefore, accurate estimates of vegetation parameters are increasingly important in the carbon cycle, the energy balance and in environmental impact assessment studies. The possibility of quantitatively estimating vegetation parameters of importance in this context using satellite data has been explored by numerous papers dealing with the subject. This report gives a summary of the present status and applicability of satellite remote sensing for estimating vegetation productivity by using vegetation index for calculating leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FPAR). Some possible approaches for use of satellite data for estimating LAI, FPAR and net primary production (NPP) on a local scale are suggested. Recommendations for continued work in the Forsmark and Oskarshamn investigation areas, where vegetation data and NDVI-images based on satellite data have been produced, are also given
Schultz, J.F.; Czuchlewski, S.J.; Quick, C.R.
This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project''s primary objective is to determine the technical feasibility of using satellite-based laser wind sensing systems for detailed study of winds, aerosols, and particulates around and downstream of suspected proliferation facilities. Extensive interactions with the relevant operational organization resulted in enthusiastic support and useful guidance with respect to measurement requirements and priorities. Four candidate wind sensing techniques were evaluated, and the incoherent Doppler technique was selected. A small satellite concept design study was completed to identify the technical issues inherent in a proof-of-concept small satellite mission. Use of a Mach-Zehnder interferometer instead of a Fabry-Perot would significantly simplify the optical train and could reduce weight, and possibly power, requirements with no loss of performance. A breadboard Mach-Zehnder interferometer-based system has been built to verify these predictions. Detailed plans were made for resolving other issues through construction and testing of a ground-based lidar system in collaboration with the University of Wisconsin, and through numerical lidar wind data assimilation studies
... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Satellite bases. 141.91 Section 141.91... OTHER CERTIFICATED AGENCIES PILOT SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a... assistant chief instructor is designated for each satellite base, and that assistant chief instructor is...
Hawkins, J.; Richardson, K.; Surratt, M.; Yang, S.; Lee, T. F.; Sampson, C. R.; Solbrig, J.; Kuciauskas, A. P.; Miller, S. D.; Kent, J.
Satellite remote sensing capabilities to monitor tropical cyclone (TC) location, structure, and intensity have evolved by utilizing a combination of operational and research and development (R&D) sensors. The microwave imagers from the operational Defense Meteorological Satellite Program [Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS)] form the "base" for structure observations due to their ability to view through upper-level clouds, modest size swaths and ability to capture most storm structure features. The NASA TRMM microwave imager and precipitation radar continue their 15+ yearlong missions in serving the TC warning and research communities. The cessation of NASA's QuikSCAT satellite after more than a decade of service is sorely missed, but India's OceanSat-2 scatterometer is now providing crucial ocean surface wind vectors in addition to the Navy's WindSat ocean surface wind vector retrievals. Another Advanced Scatterometer (ASCAT) onboard EUMETSAT's MetOp-2 satellite is slated for launch soon. Passive microwave imagery has received a much needed boost with the launch of the French/Indian Megha Tropiques imager in September 2011, basically greatly supplementing the very successful NASA TRMM pathfinder with a larger swath and more frequent temporal sampling. While initial data issues have delayed data utilization, current news indicates this data will be available in 2013. Future NASA Global Precipitation Mission (GPM) sensors starting in 2014 will provide enhanced capabilities. Also, the inclusion of the new microwave sounder data from the NPP ATMS (Oct 2011) will assist in mapping TC convective structures. The National Polar orbiting Partnership (NPP) program's VIIRS sensor includes a day night band (DNB) with the capability to view TC cloud structure at night when sufficient lunar illumination exits. Examples highlighting this new capability will be discussed in concert with additional data fusion efforts.
Bi, Siwen; Zhen, Ming; Yang, Song; Lin, Xuling; Wu, Zhiqiang
According to the development and application needs of Remote Sensing Science and technology, Prof. Siwen Bi proposed quantum remote sensing. Firstly, the paper gives a brief introduction of the background of quantum remote sensing, the research status and related researches at home and abroad on the theory, information mechanism and imaging experiments of quantum remote sensing and the production of principle prototype.Then, the quantization of pure remote sensing radiation field, the state function and squeezing effect of quantum remote sensing radiation field are emphasized. It also describes the squeezing optical operator of quantum light field in active imaging information transmission experiment and imaging experiments, achieving 2-3 times higher resolution than that of coherent light detection imaging and completing the production of quantum remote sensing imaging prototype. The application of quantum remote sensing technology can significantly improve both the signal-to-noise ratio of information transmission imaging and the spatial resolution of quantum remote sensing .On the above basis, Prof.Bi proposed the technical solution of active imaging information transmission technology of satellite borne quantum remote sensing, launched researches on its system composition and operation principle and on quantum noiseless amplifying devices, providing solutions and technical basis for implementing active imaging information technology of satellite borne Quantum Remote Sensing.
Chen, Chia-Ray; Hwang, Feng-Tai; Hsueh, Chuang-Wei
Revisiting time and global coverage are two major requirements for most of the remote sensing satellites. Constellation of satellites can get the benefit of short revisit time and global coverage. Typically, remote sensing satellites prefer to choose Sun Synchronous Orbit (SSO) because of fixed revisiting time and Sun beta angle. The system design and mission operation will be simple and straightforward. However, if we focus on providing remote sensing and store-and-forward communication services for low latitude countries, Sun Synchronous Orbit will not be the best choice because we need more satellites to cover the communication service gap in low latitude region. Sometimes the design drivers for remote sensing payloads are conflicted with the communication payloads. For example, lower orbit altitude is better for remote sensing payload performance, but the communication service zone will be smaller and we need more satellites to provide all time communication service. The current studies focus on how to provide remote sensing and communication services for low latitude countries. A cost effective approach for the mission, i.e. constellation of microsatellites, will be evaluated in this paper.
Christopher, S. A.; Feng, N.; Guo, Y.; Hong, S.
Severe yellow haze hit a vast portion of Eastern China during the second week on June, 2012, as large area in Hubei, Henan, Hunan, Jiangsu, Anhui, Jiangxi, Shandong, Zhejiang provinces and Shanghai city were covered by lingering haze. This massive haze conditions caused considerable inconvenience to people's daily lives. Previous global air quality studies have also shown that Eastern China is one of regions with highest fine particulate matter (PM2.5) concentrations around the world. In this study, we estimate spatial and temporal variations of PM2.5 concentrations using satellite observations of this severe haze pollution on June, 2012. Satellite derived Aerosol Optical Thickness (AOT), sites measured hourly PM2.5 and meteorological fields from surface are statistically correlated based on a multiple regression model. We also explore the utility of higher spatial resolution aerosol retrieval from MODIS. Both satellite-derived and in-situ values have peak daily mean concentrations of approximately 400 μg m-3 on June 12th, 2012 in the City of Wuhan, which is nearly 10 times of the primary standard of PM2.5 concentration of China's "Ambient Air Quality Standards" (35 μg m-3). Cities in the Eastern China, e.g. Nanjing, Hangzhou and Nanchang, have also witnessed similar peak values, along with heavy smog during the same period. Satellite observations in this case study demonstrate that the transport of smoke plumes can be one of the main drivers of regional haze pollution over Eastern China. Comparing to the U.S., current limited ground-based stations is one of the biggest problem to develop the PM2.5 monitoring program over China. Our results may suggest the potential of combining satellite remote sensing with atmospheric model to map the PM2.5 spatial concentration over the nationwide level, which can further accelerate the construction of PM2.5 monitoring network over China.
Clandillon, Stephen; Yésou, Hervé; Schneiderhan, Tobias; de Boissezon, Hélène; de Fraipont, Paul
During disasters rescue and relief organisations need quick access to reliable and accurate information to be better equipped to do their job. It is increasingly felt that satellites offer a unique near real time (NRT) tool to aid disaster management. A short introduction to the International Charter 'Space and Major Disasters', in operation since 2000 promoting worldwide cooperation among member space agencies, will be given as it is the foundation on which satellite-based, emergency response, damage assessment has been built. Other complementary mechanisms will also be discussed. The user access, triggering mechanism, an essential component for this user-driven service, will be highlighted with its 24/7 single access point. Then, a clear distinction will be made between data provision and geo-information delivery mechanisms to underline the user need for geo-information that is easily integrated into their working environments. Briefly, the path to assured emergency response product quality will be presented beginning with user requirements, expressed early-on, for emergency response value-adding services. Initiatives were then established, supported by national and European institutions, to develop the sector, with SERTIT and DLR being key players, providing support to decision makers in headquarters and relief teams in the field. To consistently meet the high quality levels demanded by users, rapid mapping has been transformed via workflow and quality control standardisation to improve both speed and quality. As such, SERTIT located in Alsace, France, and DLR/ZKI from Bavaria, Germany, join their knowledge in this presentation to report about recent standards as both have ISO certified their rapid mapping services based on experienced, well-trained, 24/7 on-call teams and established systems providing the first crisis analysis product in 6 hours after satellite data reception. The three main product types provided are then outlined: up-to-date pre
To understand and assess the effect of the sensor spectral response function (SRF) on the accuracy of the top of the atmosphere (TOA) Rayleigh-scattering radiance computation, new TOA Rayleigh radiance lookup tables (LUTs) over global oceans and inland waters have been generated. The new Rayleigh LUTs include spectral coverage of 335-2555 nm, all possible solar-sensor geometries, and surface wind speeds of 0-30 m/s. Using the new Rayleigh LUTs, the sensor SRF effect on the accuracy of the TOA Rayleigh radiance computation has been evaluated for spectral bands of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite and the Joint Polar Satellite System (JPSS)-1, showing some important uncertainties for VIIRS-SNPP particularly for large solar- and/or sensor-zenith angles as well as for large Rayleigh optical thicknesses (i.e., short wavelengths) and bands with broad spectral bandwidths. To accurately account for the sensor SRF effect, a new correction algorithm has been developed for VIIRS spectral bands, which improves the TOA Rayleigh radiance accuracy to ~0.01% even for the large solar-zenith angles of 70°-80°, compared with the error of ~0.7% without applying the correction for the VIIRS-SNPP 410 nm band. The same methodology that accounts for the sensor SRF effect on the Rayleigh radiance computation can be used for other satellite sensors. In addition, with the new Rayleigh LUTs, the effect of surface atmospheric pressure variation on the TOA Rayleigh radiance computation can be calculated precisely, and no specific atmospheric pressure correction algorithm is needed. There are some other important applications and advantages to using the new Rayleigh LUTs for satellite remote sensing, including an efficient and accurate TOA Rayleigh radiance computation for hyperspectral satellite remote sensing, detector-based TOA Rayleigh radiance computation, Rayleigh radiance calculations for high altitude
Steven P. Norman; William W. Hargrove; Joseph P. Spruce; William M. Christie; Sean W. Schroeder
For a higher resolution version of this file, please use the following link: www.geobabble.orgSatellite-based remote sensing can assist forest managers with their need to recognize disturbances and track recovery. Despite the long...
Dalezios, Nicolas; Dercas, Nicholas; Tarquis, Ana Maria
Water for agricultural use represents the largest share among all water uses. Vulnerability in agriculture is influenced, among others, by extended periods of water shortage in regions exposed to droughts. Advanced technological approaches and methodologies, including remote sensing, are increasingly incorporated for the assessment of irrigation water requirements. In this paper, remote sensing techniques are integrated for the estimation and monitoring of crop evapotranspiration ETc. The study area is Thessaly central Greece, which is a drought-prone agricultural region. Cotton fields in a small agricultural sub-catchment in Thessaly are used as an experimental site. Daily meteorological data and weekly field data are recorded throughout seven (2004-2010) growing seasons for the computation of reference evapotranspiration ETo, crop coefficient Kc and cotton crop ETc based on conventional data. Satellite data (Landsat TM) for the corresponding period are processed to estimate cotton crop coefficient Kc and cotton crop ETc and delineate its spatiotemporal variability. The methodology is applied for monitoring Kc and ETc during the growing season in the selected sub-catchment. Several error statistics are used showing very good agreement with ground-truth observations.
Christopher, S. A.
Satellite Remote Sensing of Particulate Matter Air Quality: Progress, Potential and Pitfalls Abstract. Fine or respirable particles with particle aerodynamic diameters less than 2.5 µm (PM2.5) affect visibility, change cloud properties, reflect and absorb incoming solar radiation, affect human health and are ubiquitous in the atmosphere. These particles are injected into the atmosphere either as primary emissions or form into the atmosphere by gas to particle conversion. There are various sources of PM2.5 including emissions from automobiles, industrial exhaust, and agricultural fires. In 2006, the United States Environmental Protection Agency (EPA) made the standards stringent by changing the 24-hr averaged PM2.5 mass values from 65µgm-3 to 35µgm-3. This was primarily based on epidemiological studies that showed the long term health benefits of making the PM2.5 standards stringent. Typically PM2.5 mass concentration is measured from surface monitors and in the United States there are nearly 1000 such filter based daily and 600 contiguous stations managed by federal, state, local, and tribal agencies. Worldwide, there are few PM2.5 ground monitors since they are expensive to purchase, maintain and operate. Satellite remote sensing therefore provides a viable method for monitoring PM2.5 from space. Although, there are several hundred satellites currently in orbit and not all of them are suited for PM2.5 air quality assessments. Typically multi-spectral reflected solar radiation measurements from space-borne sensors are converted to aerosol optical depth (AOD) which is a measure of the column (surface to top of atmosphere) integrated extinction (absorption plus scattering). This column AOD (usually at 550 nm) is often converted to PM2.5 mass near the ground using various techniques. In this presentation we discuss the progress over the last decade on assessing PM2.5 from satellites; outline the potential and discuss the various pitfalls that one encounters. We
Wessels, R. L.; Griswold, J. P.
Satellite remote sensing provided timely observations of the volcanic unrest and several months-long eruption at Sinabung Volcano, Indonesia. Visible to thermal optical and synthetic aperture radar (SAR) systems provided frequent observations of Sinabung. High resolution image data with spatial resolutions from 0.5 to 1.5m offered detailed measurements of early summit deformation and subsequent lava dome and lava flow extrusion. The high resolution data were captured by commercial satellites such as WorldView-1 and -2 visible to near-infrared (VNIR) sensors and by CosmoSkyMed, Radarsat-2, and TerraSar-X SAR systems. Less frequent 90 to 100m spatial resolution night time thermal infrared (TIR) observations were provided by ASTER and Landsat-8. The combination of data from multiple sensors allowed us to construct a more complete timeline of volcanic activity than was available via only ground-based observations. This satellite observation timeline documents estimates of lava volume and effusion rates and major explosive and lava collapse events. Frequent, repeat volume estimates suggest at least three high effusion rate pulses of up to 20 m3/s occurred during the first three months of lava effusion with an average effusion rate of 6m3/s from January 2014 to August 2014. Many of these rates and events show some correlation to variations in the Real-time Seismic-Amplitude Measurement (RSAM) documented by the Indonesian Center for Volcanology and Geologic Hazard Mitigation (CVGHM).
Gao, H.; Zhang, S.; Zhao, G.; Li, Y.
With a total global capacity of more than 6000 km3, reservoirs play a key role in the hydrological cycle and in water resources management. However, essential reservoir data (e.g., elevation, storage, and evaporation loss) are usually not shared at a large scale. While satellite remote sensing offers a unique opportunity for monitoring large reservoirs from space, the commonly used radar altimeters can only detect storage variations of about 15% of global lakes at a repeat period of 10 days or longer. To advance the capabilities of reservoir sensing, we developed a series of algorithms geared towards generating long term reservoir records at improved spatial coverage, and at improved temporal resolution. To this goal, observations are leveraged from multiple satellite sensors, which include radar/laser altimeters, imagers, and passive microwave radiometers. In South Asia, we demonstrate that reservoir storage can be estimated under all-weather conditions at a 4 day time step, with the total capacity of monitored reservoirs increased to 45%. Within the Continuous United States, a first Landsat based evaporation loss dataset was developed (containing 204 reservoirs) from 1984 to 2011. The evaporation trends of these reservoirs are identified and the causes are analyzed. All of these algorithms and products were validated with gauge observations. Future satellite missions, which will make significant contributions to monitoring global reservoirs, are also discussed.
sensed satellite data using open source support. Richa Sharma .... Decision tree classification techniques have been .... the USGS Earth Resource Observation Systems. (EROS) ... for shallow water, 11% were for sparse and dense built-up ...
Piester, D.; Rost, M.; Fujieda, M.; Feldmann, T.; Bauch, A.
In the global network of institutions engaged with the realization of International Atomic Time (TAI), atomic clocks and time scales are compared by means of the Global Positioning System (GPS) and by employing telecommunication satellites for two-way satellite time and frequency transfer (TWSTFT). The frequencies of the state-of-the-art primary caesium fountain clocks can be compared at the level of 10−15 (relative, 1 day averaging) and time scales can be synchronized...
Crawford, T. N.; Schaeffer, B. A.
Anthropogenic nutrient pollution is a major stressor of aquatic ecosystems around the world. In the United States, states and tribes can adopt numeric water quality values (i.e. criteria) into their water quality management standards to protect aquatic life from eutrophication impacts. However, budget and resource constraints have limited the ability of many states and tribes to collect the water quality monitoring data needed to derive numeric criteria. Over the last few decades, satellite technology has provided water quality measurements on a global scale over long time periods. Water quality managers are finding the data provided by satellite technology useful in managing eutrophication impacts in coastal waters, estuaries, lakes, and reservoirs. In recent years EPA has worked with states and tribes to derive remotely sensed numeric Chl-a criteria for coastal waters with limited field-based data. This approach is now being expanded and used to derive Chl-a criteria in freshwater systems across the United States. This presentation will cover EPA's approach to derive numeric Chl-a criteria using satellite remote sensing, recommendations to improve satellite sensors to expand applications, potential areas of interest, and the challenges of using remote sensing to establish water quality management goals, as well as provide a case in which this approach has been applied.
We estimated surface salinity flux and solar penetration from satellite data, and performed model simulations to examine the impact of including the satellite estimates on temperature, salinity, and dissolved oxygen distributions on the Louisiana continental shelf (LCS) near the annual hypoxic zone. Rainfall data from the Tropical Rainfall Measurement Mission (TRMM) were used for the salinity flux, and the diffuse attenuation coefficient (Kd) from Moderate Resolution Imaging Spectroradiometer (MODIS) were used for solar penetration. Improvements in the model results in comparison with in situ observations occurred when the two types of satellite data were included. Without inclusion of the satellite-derived surface salinity flux, realistic monthly variability in the model salinity fields was observed, but important inter-annual variability wasmissed. Without inclusion of the satellite-derived light attenuation, model bottom water temperatures were too high nearshore due to excessive penetration of solar irradiance. In general, these salinity and temperature errors led to model stratification that was too weak, and the model failed to capture observed spatial and temporal variability in water-column vertical stratification. Inclusion of the satellite data improved temperature and salinity predictions and the vertical stratification was strengthened, which improved prediction of bottom-water dissolved oxygen. The model-predicted area of bottom-water hypoxia on the
Lee, S.; Ryu, Y.; Jiang, C.
Satellite based remote sensing has been used to monitor plant phenology. Numerous studies have generally utilized normalized difference vegetation index (NDVI) to quantify phenological patterns and changes in regional to the global scales. Obtaining the NDVI values during summer in East Asian Monsoon regions is important because most plants grow vigorously in this season. However, satellite derived NDVI data are error prone to clouds during most of the period. Various methods have attempted to reduce the effect of cloud in temporal and spatial NDVI monitoring; the fundamental solution is to have a large data pool that includes multiple images in short period and supplements NDVI values in same period. Multiple images of geostationary satellite in a day can be a method to expand the pool. In this study, we suggest an approach that minimizes data gaps in NDVI of the day through geostationary satellite derived NDVI composition. We acquired data from Geostationary Ocean Color Imager (GOCI) which is a satellite that was launched to monitor ocean around the Korean peninsula, China, Japan and Russia. The satellite observes eight times per day (09:00 - 16:00, every hour) at 500 x 500 m resolution from 2011 to 2015. GOCI red- and near infrared radiance was converted into surface reflectance by using 6S Radiative Transfer Model (6S). We calculated NDVI tiles for each of observed eight tiles per day and made one day NDVI through maximum-value composite method. We evaluated the composite GOCI derived NDVI by comparing with daily MODIS-derived NDVI (composited from MOD09GA and MYD09GA), 16-day Landsat 8-derived NDVI, and in-situ light emitting diode (LED) NDVI measurements at a homogeneous deciduous forest and rice paddy sites. We found that GOCI-derived NDVI maps revealed little data gaps compared to MODIS and Landsat, and GOCI derived NDVI time series were smoother than MODIS derived NDVI time series in summer. GOCI-derived NDVI agreed well with in-situ observations of NDVI
Grimes, D Jay; Ford, Tim E; Colwell, Rita R; Baker-Austin, Craig; Martinez-Urtaza, Jaime; Subramaniam, Ajit; Capone, Douglas G
Satellite-based remote sensing of marine microorganisms has become a useful tool in predicting human health risks associated with these microscopic targets. Early applications were focused on harmful algal blooms, but more recently methods have been developed to interrogate the ocean for bacteria. As satellite-based sensors have become more sophisticated and our ability to interpret information derived from these sensors has advanced, we have progressed from merely making fascinating pictures from space to developing process models with predictive capability. Our understanding of the role of marine microorganisms in primary production and global elemental cycles has been vastly improved as has our ability to use the combination of remote sensing data and models to provide early warning systems for disease outbreaks. This manuscript will discuss current approaches to monitoring cyanobacteria and vibrios, their activity and response to environmental drivers, and will also suggest future directions.
Cosentino, B.L.; Lillesand, T.M.
Attention is given to an initial research project being performed by the University of Wisconsin-Madison, Environmental Remote Sensing Center in conjunction with seven local, state, and federal agencies to implement automated statewide land cover mapping using satellite remote sensing and geographical information system (GIS) techniques. The basis, progress, and future research needs for this mapping program are presented. The research efforts are directed toward strategies that integrate satellite remote sensing and GIS techniques in the generation of land cover data for multiple users of land cover information. The project objectives are to investigate methodologies that integrate satellite data with other imagery and spatial data resident in emerging GISs in the state for particular program needs, and to develop techniques that can improve automated land cover mapping efficiency and accuracy. 10 refs
Papadavid, Georgios; Kountios, Georgios; Bournaris, T.; Michailidis, Anastasios; Hadjimitsis, Diofantos G.
Nowadays, the remote sensing techniques have a significant role in all the fields of agricultural extensions as well as agricultural economics and education but they are used more specifically in hydrology. The aim of this paper is to demonstrate the use of field spectroscopy for validation of the satellite data and how combination of remote sensing techniques and field spectroscopy can have more accurate results for irrigation purposes. For this reason vegetation indices are used which are mostly empirical equations describing vegetation parameters during the lifecycle of the crops. These numbers are generated by some combination of remote sensing bands and may have some relationship to the amount of vegetation in a given image pixel. Due to the fact that most of the commonly used vegetation indices are only concerned with red-near-infrared spectrum and can be divided to perpendicular and ratio based indices the specific goal of the research is to illustrate the effect of the atmosphere to those indices, in both categories. In this frame field spectroscopy is employed in order to derive the spectral signatures of different crops in red and infrared spectrum after a campaign of ground measurements. The main indices have been calculated using satellite images taken at interval dates during the whole lifecycle of the crops by using a GER 1500 spectro-radiomete. These indices was compared to those extracted from satellite images after applying an atmospheric correction algorithm -darkest pixel- to the satellite images at a pre-processing level so as the indices would be in comparable form to those of the ground measurements. Furthermore, there has been a research made concerning the perspectives of the inclusion of the above mentioned remote satellite techniques to agricultural education pilot programs.
Siemann, Amanda Lynn
The dynamics of the energy fluxes between the land surface and the atmosphere drive local and regional climate and are paramount to understand the past, present, and future changes in climate. Although global reanalysis datasets, land surface models (LSMs), and climate models estimate these fluxes by simulating the physical processes involved, they merely simulate our current understanding of these processes. Global estimates of the terrestrial, surface energy fluxes based on observations allow us to capture the dynamics of the full climate system. Remotely-sensed satellite data is the source of observations of the land surface which provide the widest spatial coverage. Although net radiation and latent heat flux global, terrestrial, surface estimates based on remotely-sensed satellite data have progressed, comparable sensible heat data products and ground heat flux products have not progressed at this scale. Our primary objective is quantifying and understanding the terrestrial energy fluxes at the Earth's surface using remotely-sensed satellite data with consistent development among all energy budget components [through the land surface temperature (LST) and input meteorology], including validation of these products against in-situ data, uncertainty assessments, and long-term trend analysis. The turbulent fluxes are constrained by the available energy using the Bowen ratio of the un-constrained products to ensure energy budget closure. All final products are within uncertainty ranges of literature values, globally. When validated against the in-situ estimates, the sensible heat flux estimates using the CFSR air temperature and constrained with the products using the MODIS albedo produce estimates closest to the FLUXNET in-situ observations. Poor performance over South America is consistent with the largest uncertainties in the energy budget. From 1984-2007, the longwave upward flux increase due to the LST increase drives the net radiation decrease, and the
Ramsey, M. S.
The ability to detect the onset of new activity at a remote volcano commonly relies on high temporal resolution thermal infrared (TIR) satellite-based observations. These observations from sensors such as AVHRR and MODIS are being used in innovative ways to produce trends of activity, which are critical for hazard response planning and scientific modeling. Such data are excellent for detection of new thermal features, volcanic plumes, and tracking changes over the hour time scale, for example. For some remote volcanoes, the lack of ground-based monitoring typically means that these sensors provide the first and only confirmation of renewed activity. However, what is lacking is the context of the higher spatial scale, which provides the volcanologist with meter-scale information on specific temperatures and changes in the composition and texture of the eruptive products. For the past eleven years, the joint US-Japanese ASTER instrument has been acquiring image-based data of volcanic eruptions around the world, including in the remote northern Pacific region. There have been more ASTER observations of Kamchatka volcanoes than any other location on the globe due mainly to an operational program put into place in 2004. Automated hot spot alarms from AVHRR data trigger ASTER acquisitions using the instrument's "rapid response" mode. Specifically for Kamchatka, this program has resulted in more than 700 additional ASTER images of the most thermally-active volcanoes (e.g., Shiveluch, Kliuchevskoi, Karymsky, Bezymianny). The scientific results from this program at these volcanoes will be highlighted. These results were strengthened by several field seasons used to map new products, collect samples for laboratory-based spectroscopy, and acquire TIR camera data. The fusion of ground, laboratory and space-based spectroscopy provided the most accurate interpretation of the eruptions and laid the ground work for future VSWIR/TIR sensors such as HyspIRI, which are a critically
Full Text Available Focused on the issue that conventional remote sensing image classification methods have run into the bottlenecks in accuracy, a new remote sensing image classification method inspired by deep learning is proposed, which is based on Stacked Denoising Autoencoder. First, the deep network model is built through the stacked layers of Denoising Autoencoder. Then, with noised input, the unsupervised Greedy layer-wise training algorithm is used to train each layer in turn for more robust expressing, characteristics are obtained in supervised learning by Back Propagation (BP neural network, and the whole network is optimized by error back propagation. Finally, Gaofen-1 satellite (GF-1 remote sensing data are used for evaluation, and the total accuracy and kappa accuracy reach 95.7% and 0.955, respectively, which are higher than that of the Support Vector Machine and Back Propagation neural network. The experiment results show that the proposed method can effectively improve the accuracy of remote sensing image classification.
Gavili Kilaneh, Narin; Mashhadi Hossainali, Masoud
Due to the recent advances in the Global Navigation Satellite System Remote sensing (GNSS¬R) applications, optimization of a satellite orbit to investigate the Earth's properties seems significant. The comparison of the GNSS direct and reflected signals received by a Low Earth Orbit (LEO) satellite introduces a new technique to remotely sense the Earth. Several GNSS¬R missions including Cyclone Global Navigation Satellite System (CYGNSS) have been proposed for different applications such as the ocean wind speed and height monitoring. The geometric optimization of the satellite orbit before starting the mission is a key step for every space mission. Since satellite constellation design varies depending on the application, we have focused on the required geometric criteria for oceanography applications in a specified region. Here, the total number of specular points, their spatial distribution and the accuracy of their position are assumed to be sufficient for oceanography applications. Gleason's method is used to determine the position of specular points. We considered the 2-D lattice and 3-D lattice theory of flower constellation to survey whether a circular orbit or an elliptical one is suitable to improve the solution. Genetic algorithm is implemented to solve the problem. To check the visibility condition between the LEO and GPS satellites, the satellite initial state is propagated by a variable step size numerical integration method. Constellation orbit parameters achieved by optimization provide a better resolution and precession for the specular points in the study area of this research.
Jones, Matthew O; Kimball, John S; Small, Eric E; Larson, Kristine M
The land surface phenology (LSP) start of season (SOS) metric signals the seasonal onset of vegetation activity, including canopy growth and associated increases in land-atmosphere water, energy and carbon (CO2) exchanges influencing weather and climate variability. The vegetation optical depth (VOD) parameter determined from satellite passive microwave remote sensing provides for global LSP monitoring that is sensitive to changes in vegetation canopy water content and biomass, and insensitive to atmosphere and solar illumination constraints. Direct field measures of canopy water content and biomass changes desired for LSP validation are generally lacking due to the prohibitive costs of maintaining regional monitoring networks. Alternatively, a normalized microwave reflectance index (NMRI) derived from GPS base station measurements is sensitive to daily vegetation water content changes and may provide for effective microwave LSP validation. We compared multiyear (2007-2011) NMRI and satellite VOD records at over 300 GPS sites in North America, and their derived SOS metrics for a subset of 24 homogenous land cover sites to investigate VOD and NMRI correspondence, and potential NMRI utility for LSP validation. Significant correlations (P<0.05) were found at 276 of 305 sites (90.5 %), with generally favorable correspondence in the resulting SOS metrics (r (2)=0.73, P<0.001, RMSE=36.8 days). This study is the first attempt to compare satellite microwave LSP metrics to a GPS network derived reflectance index and highlights both the utility and limitations of the NMRI data for LSP validation, including spatial scale discrepancies between local NMRI measurements and relatively coarse satellite VOD retrievals.
Full Text Available In this study, two different methods were applied to derive daily and monthly sunshine duration based on high-resolution satellite products provided by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT Satellite Application Facility on Climate Monitoring using data from Meteosat Second Generation (MSG SEVIRI (Spinning Enhanced Visible and Infrared Imager. The satellite products were either hourly cloud type or hourly surface incoming direct radiation. The satellite sunshine duration estimates were not found to be significantly different using the native 15-minute temporal resolution of SEVIRI. The satellite-based sunshine duration products give additional spatial information over the European continent compared with equivalent in situ-based products. An evaluation of the satellite sunshine duration by product intercomparison and against station measurements was carried out to determine their accuracy. The satellite data were found to be within ±1 h/day compared to high-quality Baseline Surface Radiation Network or surface synoptic observations (SYNOP station measurements. The satellite-based products differ more over the oceans than over land, mainly because of the treatment of fractional clouds in the cloud type-based sunshine duration product. This paper presents the methods used to derive the satellite sunshine duration products and the performance of the different retrievals. The main benefits and disadvantages compared to station-based products are also discussed.
Nakajima, I; Inokuchi, S; Tajima, T; Takahashi, T
An experiment to transmit ultrasonic tomographic section images required for remote medical diagnosis and care was conducted using the mobile telecommunication satellite OSCAR-10. The images received showed the intestinal condition of a patient incapable of verbal communication, however the image screen had a fairly coarse particle structure. On the basis of these experiments, were considered as the transmission of ultrasonic tomographic images extremely effective in remote diagnosis.
Carmichael, J.; Eldridge, R.; Friedman, E.; Keitz, E.
An approach to the development of a prioritized list of scientific goals in atmospheric research is provided. The results of the analysis are used to estimate the contribution of various spacecraft/remote sensor combinations for each of several important constituents of the stratosphere. The evaluation of the combinations includes both single-instrument and multiple-instrument payloads. Attention was turned to the physical and chemical features of the atmosphere as well as the performance capability of a number of atmospheric remote sensors. In addition, various orbit considerations were reviewed along with detailed information on stratospheric aerosols and the impact of spacecraft environment on the operation of the sensors.
Maharana, P. K.; Goel, P. S.
The effect of flexible arrays on sun tracking for the IRS satellite is studied. Equations of motion of satellites carrying a rotating flexible appendage are developed following the Newton-Euler approach and utilizing the constrained modes of the appendage. The drive torque, detent torque and friction torque in the SADA are included in the model. Extensive simulations of the slewing motion are carried out. The phenomena of back-stepping, step-missing, step-slipping and the influences of array flexibility in the acquisition mode are observed for certain combinations of parameters.
Bandaru, V.; Jones, C. D.; Sedano, F.; Sahajpal, R.; Jin, H.; Skakun, S.; Pnvr, K.; Kommareddy, A.; Reddy, A.; Hurtt, G. C.; Izaurralde, R. C.
Agricultural croplands act as both sources and sinks of atmospheric carbon dioxide (CO2); absorbing CO2 through photosynthesis, releasing CO2 through autotrophic and heterotrophic respiration, and sequestering CO2 in vegetation and soils. Part of the carbon captured in vegetation can be transported and utilized elsewhere through the activities of food, fiber, and energy production. As well, a portion of carbon in soils can be exported somewhere else by wind, water, and tillage erosion. Thus, it is important to quantify how land use and land management practices affect the net carbon balance of croplands. To monitor the impacts of various agricultural activities on carbon balance and to develop management strategies to make croplands to behave as net carbon sinks, it is of paramount importance to develop consistent and high resolution cropland carbon flux estimates. Croplands are typically characterized by fine scale heterogeneity; therefore, for accurate carbon flux estimates, it is necessary to account for the contribution of each crop type and their spatial distribution. As part of NASA CMS funded project, a satellite based Cropland Carbon Monitoring System (CCMS) was developed to estimate spatially resolved crop specific carbon fluxes over large regions. This modeling framework uses remote sensing version of Environmental Policy Integrated Climate Model and satellite derived crop parameters (e.g. leaf area index (LAI)) to determine vertical and lateral carbon fluxes. The crop type LAI product was developed based on the inversion of PRO-SAIL radiative transfer model and downscaled MODIS reflectance. The crop emergence and harvesting dates were estimated based on MODIS NDVI and crop growing degree days. To evaluate the performance of CCMS framework, it was implemented over croplands of Nebraska, and estimated carbon fluxes for major crops (i.e. corn, soybean, winter wheat, grain sorghum, alfalfa) grown in 2015. Key findings of the CCMS framework will be presented
S. I. Khan
Full Text Available Study of hydro-climatology at a range of temporal scales is important in understanding and ultimately mitigating the potential severe impacts of hydrological extreme events such as floods and droughts. Using daily in-situ data over the last two decades combined with the recently available multiple-years satellite remote sensing data, we analyzed and simulated, with a distributed hydrologic model, the hydro-climatology in Nzoia, one of the major contributing sub-basins of Lake Victoria in the East African highlands. The basin, with a semi arid climate, has no sustained base flow contribution to Lake Victoria. The short spell of high discharge showed that rain is the prime cause of floods in the basin. There is only a marginal increase in annual mean discharge over the last 21 years. The 2-, 5- and 10- year peak discharges, for the entire study period showed that more years since the mid 1990's have had high peak discharges despite having relatively less annual rain. The study also presents the hydrologic model calibration and validation results over the Nzoia basin. The spatiotemporal variability of the water cycle components were quantified using a hydrologic model, with in-situ and multi-satellite remote sensing datasets. The model is calibrated using daily observed discharge data for the period between 1985 and 1999, for which model performance is estimated with a Nash Sutcliffe Efficiency (NSCE of 0.87 and 0.23% bias. The model validation showed an error metrics with NSCE of 0.65 and 1.04% bias. Moreover, the hydrologic capability of satellite precipitation (TRMM-3B42 V6 is evaluated. In terms of reconstruction of the water cycle components the spatial distribution and time series of modeling results for precipitation and runoff showed considerable agreement with the monthly model runoff estimates and gauge observations. Runoff values responded to precipitation events that occurred across the catchment during the wet season from March to
Nielsen, Søren Zebitz
This thesis studies the spatio-temporal patterns and trends in NO2 air pollution over Denmark using the satellite remote sensing product OMNO2e retrieved from the OMI instrument on the NASA AURA satellite. These data are related to in situ measurements of NO2 made at four rural and four urban...... measured in Denmark. Trends in the data are assessed and declining trends are seen over several European cities, whereas no significant trends are found in the Danish area. The mean distribution of NO2 from the satellite data is also used to evaluate the NOx emission inventory....
Since the launch of Sputnik I in 1957, satellite radio beacons have been used to measure the total electron content of the ionosphere. A review of the role of satellite beacons in studies of the vertical and spatial structure of the total electron content and on the occurrence of plasma irregularities, both of which affect transionospheric radio signals, is presented. Measurements of Faraday rotation and time of flight give information on the topside of the ionosphere and on the protonosphere. Morphological studies show that the slab thickness of the ionosphere depends on the solar index but is approximately independent of geographical location. Scintillation of amplitude, phase, polarization, and angle provide information on plasma irregularity occurrence in space and time. (author). 23 refs., 16 figs ., 4 tabs
Mishchenko, M I; Cairns, B; Chowdhary, J; Geogdzhayev, I V; Liu, L; Travis, L D
This review paper outlines the rationale for long-term monitoring of the global distribution of natural and anthropogenic aerosols and clouds with specificity, accuracy, and coverage necessary for a reliable quantification of the direct and indirect aerosol effects on climate. We discuss the hierarchy of passive instruments suitable for aerosol remote sensing and give examples of aerosol retrievals obtained with instruments representing the low and the high end of this hierarchy
Sasaki, Takanori; Tanabu, Yoshimine; Fujita, Shigetaka; Zhao Wenhui
Interest in nuclear power generation is increasing by rising of power demand and environmental concern. It is important more and more to confirm and show the safety operation of nuclear plants, which is useful to remove anxiety of residents. Satellite remote sensing is one of the way of it. Large observation width and long and continuous observation period are advantage of satellite remote sensing. In addition, it is very important to be able to monitor without visitation on the site. We have continued local area environmental analysis using various satellites. MODIS on Terra and Aqua which are NASA satellites received by Hachinohe Institute of Technology is mainly used. According to these results, we have shown that combined analysis of various information parameters such as land surface temperature, geographical changes, vegetation, etc. is very effective to monitor environmental changes. In these analyses, error detection is very important. Therefore, enough storage data with continuously monitoring in usual state is necessary. Moreover, it is thought that the confirmation of stable operation of plants by means of continuous monitoring can contribute to reduce residents' anxiety of nuclear power plant. Additionally, in the case that the change of influence on surroundings is detected, it is possible to grasp the situation and take measure in early stage by error detection. In this paper, as an possible example of continuous monitoring using satellite remote sensing, we introduce the result of analysis and investigation of which changes of sea surface temperature and chlorophyll concentration on the sea around power plant. (author)
Roy, D.; Purna Kumari, B.; Manju Sarma, M.; Aparna, N.; Gopal Krishna, B.
The quality of Remote Sensing data is an important parameter that defines the extent of its usability in various applications. The data from Remote Sensing satellites is received as raw data frames at the ground station. This data may be corrupted with data losses due to interferences during data transmission, data acquisition and sensor anomalies. Thus it is important to assess the quality of the raw data before product generation for early anomaly detection, faster corrective actions and product rejection minimization. Manual screening of raw images is a time consuming process and not very accurate. In this paper, an automated process for identification and quantification of losses in raw data like pixel drop out, line loss and data loss due to sensor anomalies is discussed. Quality assessment of raw scenes based on these losses is also explained. This process is introduced in the data pre-processing stage and gives crucial data quality information to users at the time of browsing data for product ordering. It has also improved the product generation workflow by enabling faster and more accurate quality estimation.
Loyola, D. G.
The satellite remote sensing retrievals are usually ill-posed inverse problems that are typically solved by finding a state vector that minimizes the residual between simulated data and real measurements. The classical inversion methods are very time-consuming as they require iterative calls to complex radiative-transfer forward models to simulate radiances and Jacobians, and subsequent inversion of relatively large matrices. In this work we present a novel and extremely fast algorithm for solving inverse problems called full-physics inverse learning machine (FP-ILM). The FP-ILM algorithm consists of a training phase in which machine learning techniques are used to derive an inversion operator based on synthetic data generated using a radiative transfer model (which expresses the "full-physics" component) and the smart sampling technique, and an operational phase in which the inversion operator is applied to real measurements. FP-ILM has been successfully applied to the retrieval of the SO2 plume height during volcanic eruptions and to the retrieval of ozone profile shapes from UV/VIS satellite sensors. Furthermore, FP-ILM will be used for the near-real-time processing of the upcoming generation of European Sentinel sensors with their unprecedented spectral and spatial resolution and associated large increases in the amount of data.
Full Text Available The successful launch of the first very high resolution (VHR satellites capable of capturing panchromatic imagery of the land surface with ground sample distance even lower than 1 m (e.g. IKONOS in 1999 or QuickBird in 2001 marked the beginning of a wholly new age in remote sensing. On January 4, 2010, images of WorldView-2 were placed on the market. Possibly it is the most sophisticated commercial VHR satellite currently orbiting the Earth and the exploitation of its data poses a challenge to researchers worldwide. Moreover, the practice of under plastic agriculture had a great development in the Mediterranean area during the past 60 years, especially in Almeria, acting as a key economic driver in the area. The goal of this work is the automatic greenhouse mapping by using Object Based Image Analysis (OBIA. The required input data will be a pan-sharpened orthoimage and a normalized digital surface model (nDSM for objects, both products generated from a WorldView-2 stereo pair. The attained results show that the very high resolution 8-band multispectral and the nDSM data improve the greenhouses automatic detection. In this way, overall accuracies higher than 90% can be achieved.
Brown, Molly E.; Essam, Timothy; Leonard, Kenneth
Famine early warning organizations have experience that has much to contribute to efforts to incorporate climate and weather information into economic and political systems. Food security crises are now caused almost exclusively by problems of food access, not absolute food availability, but the role of monitoring agricultural production both locally and globally remains central. The price of food important to the understanding of food security in any region, but it needs to be understood in the context of local production. Thus remote sensing is still at the center of much food security analysis, along with an examination of markets, trade and economic policies during food security analyses. Technology including satellite remote sensing, earth science models, databases of food production and yield, and modem telecommunication systems contributed to improved food production information. Here we present an econometric approach focused on bringing together satellite remote sensing and market analysis into food security assessment in the context of early warning.
Schultz, L. A.; Molthan, A.; McGrath, K.; Bell, J. R.; Cole, T.; Burks, J.
In recent years, the NWS has developed a GIS-based application, called the Damage Assessment Toolkit (DAT), to conduct storm surveys after severe weather events. At present, the toolkit is primarily used for tornado damage surveys and facilitates the identification of damage indicators in accordance with the Enhanced Fujita (EF) intensity scale by allowing surveyors to compare time- and geo-tagged photos against the EF scale guidelines. Mobile and web-based applications provide easy access to the DAT for NWS personnel while performing their duties in the field or office. Multispectral satellite remote sensing imagery has demonstrated benefits for the detection and mapping of damage tracks caused by tornadoes, especially for long-track events and/or areas not easily accessed by NWS personnel. For example, imagery from MODIS, Landsat 7, Landsat 8, ASTER, Sentinel 2, and commercial satellites, collected and distributed in collaboration with the USGS Hazards Data Distribution System, have been useful for refining track location and extent through a "bird's eye" view of the damaged areas. The NASA Short-term Prediction Research and Transition (SPoRT) Center has been working with the NWS and USGS to provide imagery and derived products from polar-orbiting satellite platforms to assist in the detection and refinement of tornado tracks as part of a NASA Applied Science: Disasters project. Working closely with select Weather Forecast Offices (WFOs) and Regional Operations Centers (ROCs) in both the NWS Central and Southern regions, high- and medium-resolution (0.5 - 30 m and 250 m - 1 km resolutions, respectively) imagery and derived products have been provided to the DAT interface for evaluation of operational utility by the NWS for their use in both the field and in the office during post event analysis. Highlighted in this presentation will be case studies where the remotely sensed imagery assisted in the adjustment of a tornado track. Examples will be shown highlighting
Downs, S. W., Jr.
Some examples are presented of the use of remote sensing in cultivated crops, forestry, and range management. Areas of concern include: the determination of crop areas and types, prediction of yield, and detection of disease; the determination of forest areas and types, timber volume estimation, detection of insect and disease attack, and forest fires; and the determination of range conditions and inventory, and livestock inventory. Articles in the literature are summarized and specific examples of work being performed at the Marshall Space Flight Center are given. Primarily, aerial photographs and photo-like ERTS images are considered.
Ren, Yingjie; Guo, Kai; Xu, Xinni; Sun, Dayu; Wang, Li
In view of the shortcomings such as the short control distance of the traditional air conditioner remote controller on the market nowadays and combining with the current smart home new mode "Cloud+ Terminal" mode, a smart home system based on internet is designed and designed to be fully applied to the simple and reliable features of the LPC1114 chip. The controller is added with temperature control module, timing module and other modules. Through the actual test, it achieved remote control air conditioning, with reliability and stability and brought great convenience to people's lives.
H. Çimen; İ. Yabanova; M. Nartkaya; S. M. Çinar
This paper presents a web based remote access microcontroller laboratory. Because of accelerated development in electronics and computer technologies, microcontroller-based devices and appliances are found in all aspects of our daily life. Before the implementation of remote access microcontroller laboratory an experiment set is developed by teaching staff for training microcontrollers. Requirement of technical teaching and industrial applications are considered when expe...
Full Text Available Fuel types is one of the most important factors that should be taken into consideration for computing spatial fire hazard and risk and simulating fire growth and intensity across a landscape. In the present study, forest fuel mapping is considered from a remote sensing perspective. The purpose is to delineate forest types by exploring the use of coarse resolution satellite remote sensing MODIS imagery. In order to ascertain how well MODIS data can provide an exhaustive classification of fuel properties a sample area characterized by mixed vegetation covers and complex topography was analysed. The study area is located in the South of Italy. Fieldwork fuel type recognitions, performed before, after and during the acquisition of remote sensing MODIS data, were used as ground-truth dataset to assess the obtained results. The method comprised the following three steps: (I adaptation of Prometheus fuel types for obtaining a standardization system useful for remotely sensed classification of fuel types and properties in the considered Mediterranean ecosystems; (II model construction for the spectral characterization and mapping of fuel types based on two different approach, maximum likelihood (ML classification algorithm and spectral Mixture Analysis (MTMF; (III accuracy assessment for the performance evaluation based on the comparison of MODIS-based results with ground-truth. Results from our analyses showed that the use of remotely sensed MODIS data provided a valuable characterization and mapping of fuel types being that the achieved classification accuracy was higher than 73% for ML classifier and higher than 83% for MTMF.
Cronje, T.; Burger, H.; Du Plessis, J.; Du Toit, J. F.; Marais, L.; Strumpfer, F.
This paper will discuss and compare recent refractive and catodioptric imager designs developed and manufactured at SunSpace for Multi Sensor Satellite Imagers with Panchromatic, Multi-spectral, Area and Hyperspectral sensors on a single Focal Plane Array (FPA). These satellite optical systems were designed with applications to monitor food supplies, crop yield and disaster monitoring in mind. The aim of these imagers is to achieve medium to high resolution (2.5m to 15m) spatial sampling, wide swaths (up to 45km) and noise equivalent reflectance (NER) values of less than 0.5%. State-of-the-art FPA designs are discussed and address the choice of detectors to achieve these performances. Special attention is given to thermal robustness and compactness, the use of folding prisms to place multiple detectors in a large FPA and a specially developed process to customize the spectral selection with the need to minimize mass, power and cost. A refractive imager with up to 6 spectral bands (6.25m GSD) and a catodioptric imager with panchromatic (2.7m GSD), multi-spectral (6 bands, 4.6m GSD), hyperspectral (400nm to 2.35μm, 200 bands, 15m GSD) sensors on the same FPA will be discussed. Both of these imagers are also equipped with real time video view finding capabilities. The electronic units could be subdivided into the Front-End Electronics and Control Electronics with analogue and digital signal processing. A dedicated Analogue Front-End is used for Correlated Double Sampling (CDS), black level correction, variable gain and up to 12-bit digitizing and high speed LVDS data link to a mass memory unit.
Murray, Nicholas J; Keith, David A; Bland, Lucie M; Ferrari, Renata; Lyons, Mitchell B; Lucas, Richard; Pettorelli, Nathalie; Nicholson, Emily
The current set of global conservation targets requires methods for monitoring the changing status of ecosystems. Protocols for ecosystem risk assessment are uniquely suited to this task, providing objective syntheses of a wide range of data to estimate the likelihood of ecosystem collapse. Satellite remote sensing can deliver ecologically relevant, long-term datasets suitable for analysing changes in ecosystem area, structure and function at temporal and spatial scales relevant to risk assessment protocols. However, there is considerable uncertainty about how to select and effectively utilise remotely sensed variables for risk assessment. Here, we review the use of satellite remote sensing for assessing spatial and functional changes of ecosystems, with the aim of providing guidance on the use of these data in ecosystem risk assessment. We suggest that decisions on the use of satellite remote sensing should be made a priori and deductively with the assistance of conceptual ecosystem models that identify the primary indicators representing the dynamics of a focal ecosystem. Copyright © 2017 Elsevier B.V. All rights reserved.
Li, Tongwen; Zhang, Chengyue; Shen, Huanfeng; Yuan, Qiangqiang; Zhang, Liangpei
Satellite remote sensing has been reported to be a promising approach for the monitoring of atmospheric PM2.5. However, the satellite-based monitoring of ground-level PM2.5 is still challenging. First, the previously used polar-orbiting satellite observations, which can be usually acquired only once per day, are hard to monitor PM2.5 in real time. Second, many data gaps exist in satellitederived PM2.5 due to the cloud contamination. In this paper, the hourly geostationary satellite (i.e., Harawari-8) observations were adopted for the real-time monitoring of PM2.5 in a deep learning architecture. On this basis, the satellite-derived PM2.5 in conjunction with ground PM2.5 measurements are incorporated into a spatio-temporal fusion model to fill the data gaps. Using Wuhan Urban Agglomeration as an example, we have successfully derived the real-time and seamless PM2.5 distributions. The results demonstrate that Harawari-8 satellite-based deep learning model achieves a satisfactory performance (out-of-sample cross-validation R2 = 0.80, RMSE = 17.49 μg/m3) for the estimation of PM2.5. The missing data in satellite-derive PM2.5 are accurately recovered, with R2 between recoveries and ground measurements of 0.75. Overall, this study has inherently provided an effective strategy for the realtime and seamless monitoring of ground-level PM2.5.
Singh, R. K.; Budde, M. E.; Senay, G. B.; Rowland, J.
Forecasting crop production in advance of crop harvest plays a significant role in drought impact management, improved food security, stabilizing food grain market prices, and poverty reduction. This becomes essential, particularly in Sub-Saharan Africa, where agriculture is a critical source of livelihoods, but lacks good quality agricultural statistical data. With increasing availability of low cost satellite data, faster computing power, and development of modeling algorithms, remotely sensed images are becoming a common source for deriving information for agricultural, drought, and water management. Many researchers have shown that the Normalized Difference Vegetation Index (NDVI), based on red and near-infrared reflectance, can be effectively used for estimating crop production and yield. Similarly, crop production and yield have been closely related to evapotranspiration (ET) also as there are strong linkages between production/yield and transpiration based on plant physiology. Thus, we combined NDVI and ET information from remotely sensed images for estimating total production and crop yield prior to crop harvest for Niger and Burkina Faso in West Africa. We identified the optimum time (dekads 23-29) for cumulating NDVI and ET and developed a new algorithm for estimating crop production and yield. We used the crop data from 2003 to 2008 to calibrate our model and the data from 2009 to 2013 for validation. Our results showed that total crop production can be estimated within 5% of actual production (R2 = 0.98) about 30-45 days before end of the harvest season. This novel approach can be operationalized to provide a valuable tool to decision makers for better drought impact management in drought-prone regions of the world.
Zoran, Maria A.; Savastru, Roxana S.; Savastru, Dan M.; Tautan, Marina N.; Baschir, Laurentiu V.
In frame of global warming, the field of urbanization and urban thermal environment are important issues among scientists all over the world. This paper investigated the influences of urbanization on urban thermal environment as well as the relationships of thermal characteristics to other biophysical variables in Bucharest metropolitan area of Romania based on satellite remote sensing imagery Landsat TM/ETM+, time series MODIS Terra/Aqua data and IKONOS acquired during 1990 - 2012 period. Vegetation abundances and percent impervious surfaces were derived by means of linear spectral mixture model, and a method for effectively enhancing impervious surface has been developed to accurately examine the urban growth. The land surface temperature (Ts), a key parameter for urban thermal characteristics analysis, was also retrieved from thermal infrared band of Landsat TM/ETM+, from MODIS Terra/Aqua datasets. Based on these parameters, the urban growth, urban heat island effect (UHI) and the relationships of Ts to other biophysical parameters have been analyzed. Results indicated that the metropolitan area ratio of impervious surface in Bucharest increased significantly during two decades investigated period, the intensity of urban heat island and heat wave events being most significant. The correlation analyses revealed that, at the pixel-scale, Ts possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively. This analysis provided an integrated research scheme and the findings can be very useful for urban ecosystem modeling.
Lafitte, Marc; Robin, Jean‑Philippe
The mission of the European Union Satellite Centre (SatCen) is “to support the decision making and actions of the European Union in the field of the CFSP and in particular the CSDP, including European Union crisis management missions and operations, by providing, at the request of the Council or the European Union High Representative, products and services resulting from the exploitation of relevant space assets and collateral data, including satellite and aerial imagery, and related services”. The SatCen Non‑Proliferation Team, part of the SatCen Operations Division, is responsible for the analysis of installations that are involved, or could be involved, in the preparation or acquisition of capabilities intended to divert the production of nuclear material for military purposes and, in particular, regarding the spread of Weapons of Mass destruction and their means of delivery. For the last four decades, satellite imagery and associated remote sensing and geospatial techniques have increasingly expanded their capabilities. The unprecedented Very High Resolution (VHR) data currently available, the improved spectral capabilities, the increasing number of sensors and ever increasing computing capacity, has opened up a wide range of new perspectives for remote sensing applications. Concurrently, the availability of open source information (OSINF), has increased exponentially through the medium of the internet. This range of new capabilities for sensors and associated remote sensing techniques have strengthened the SatCen analysis capabilities for the monitoring of suspected proliferation installations for the detection of undeclared nuclear facilities, processes and activities. The combination of these remote sensing techniques, imagery analysis, open source investigation and their integration into Geographic Information Systems (GIS), undoubtedly improve the efficiency and comprehensive analysis capability provided by the SatCen to the EU stake‑holders. The
Full Text Available In recent years, the area of plastic-mulched farmland (PMF has undergone rapid growth and raised remarkable environmental problems. Therefore, mapping the PMF plays a crucial role in agricultural production, environmental protection and resource management. However, appropriate data selection criteria are currently lacking. Thus, this study was carried out in two main plastic-mulching practice regions, Jizhou and Guyuan, to look for an appropriate spatial scale for mapping PMF with remote sensing. The average local variance (ALV function was used to obtain the appropriate spatial scale for mapping PMF based on the GaoFen-1 (GF-1 satellite imagery. Afterwards, in order to validate the effectiveness of the selected method and to interpret the relationship between the appropriate spatial scale derived from the ALV and the spatial scale with the highest classification accuracy, we classified the imagery with varying spatial resolution by the Support Vector Machine (SVM algorithm using the spectral features, textural features and the combined spectral and textural features respectively. The results indicated that the appropriate spatial scales from the ALV lie between 8 m and 20 m for mapping the PMF both in Jizhou and Guyuan. However, there is a proportional relation: the spatial scale with the highest classification accuracy is at the 1/2 location of the appropriate spatial scale generated from the ALV in Jizhou and at the 2/3 location of the appropriate spatial scale generated from the ALV in Guyuan. Therefore, the ALV method for quantitatively selecting the appropriate spatial scale for mapping PMF with remote sensing imagery has theoretical and practical significance.
Cyanobacterial harmful algal blooms (CyanoHAB) are thought to be increasing globally over the past few decades, but relatively little quantitative information is available about the spatial extent of blooms. Satellite remote sensing provides a potential technology for identifying...
Hashim, M; Pour, A B; Onn, C H
Remote sensing technology is an important tool to analyze vegetation dynamics, quantifying vegetation fraction of Earth's agricultural and natural vegetation. In optical remote sensing analysis removing atmospheric interferences, particularly distribution of cloud contaminations, are always a critical task in the tropical climate. This paper suggests a fast and alternative approach to remove cloud and shadow contaminations for Landsat Enhanced Thematic Mapper + (ETM + ) multi temporal datasets. Band 3 and Band 4 from all the Landsat ETM + dataset are two main spectral bands that are very crucial in this study for cloud removal technique. The Normalise difference vegetation index (NDVI) and the normalised difference soil index (NDSI) are two main derivatives derived from the datasets. Change vector analysis is used in this study to seek the vegetation dynamics. The approach developed in this study for cloud optimizing can be broadly applicable for optical remote sensing satellite data, which are seriously obscured with heavy cloud contamination in the tropical climate
Sader, Steven A.; Jadkowski, Mark A.
A cooperative commercial development project designed to focus on cost-effective and practical applications of satellite remote sensing in forest management is discussed. The project, initiated in September, 1988 is being executed in three phases: (1) development of a forest resource inventory and geographic information system (GIS) updating systems; (2) testing and evaluation of remote-sensing products against forest industry specifications; and (3) integration of remote-sensing services and products in an operational setting. An advisory group represented by eleven major forest-product companies will provide direct involvement of the target market. The advisory group will focus on the following questions: Does the technology work for them? How can it be packaged to provide the needed forest-management information? Can the products and information be provided in a cost-effective manner?
Datla, Raju; Weinreb, Michael; Rice, Joseph; Johnson, B Carol; Shirley, Eric; Cao, Changyong
This paper traces the cooperative efforts of scientists at the National Oceanic and Atmospheric Administration (NOAA) and the National Institute of Standards and Technology (NIST) to improve the calibration of operational satellite sensors for remote sensing of the Earth's land, atmosphere and oceans. It gives a chronological perspective of the NOAA satellite program and the interactions between the two agencies' scientists to address pre-launch calibration and issues of sensor performance on orbit. The drive to improve accuracy of measurements has had a new impetus in recent years because of the need for improved weather prediction and climate monitoring. The highlights of this cooperation and strategies to achieve SI-traceability and improve accuracy for optical satellite sensor data are summarized.
Herron-Thorpe, F. L.; Mount, G. H.; Emmons, L. K.; Lamb, B. K.; Jaffe, D. A.; Wigder, N. L.; Chung, S. H.; Zhang, R.; Woelfle, M.; Vaughan, J. K.; Leung, F. T.
The WSU AIRPACT air quality modeling system for the Pacific Northwest forecasts hourly levels of aerosols and atmospheric trace gases for use in determining potential health and ecosystem impacts by air quality managers. AIRPACT uses the WRF/SMOKE/CMAQ modeling framework, derives dynamic boundary conditions from MOZART-4 forecast simulations with assimilated MOPITT CO, and uses the BlueSky framework to derive fire emissions. A suite of surface measurements and satellite-based remote sensing data products across the AIRPACT domain are used to evaluate and improve model performance. Specific investigations include anthropogenic emissions, wildfire simulations, and the effects of long-range transport on surface ozone. In this work we synthesize results for multiple comparisons of AIRPACT with satellite products such as IASI ammonia, AIRS carbon monoxide, MODIS AOD, OMI tropospheric ozone and nitrogen dioxide, and MISR plume height. Features and benefits of the newest version of AIRPACT's web-interface are also presented.
Aiken, John G.; Swan, Peter A.; Leopold, Ray J.
Design considerations are discussed for Low Earth Orbit (LEO) satellite based telecommunications networks. The satellites are assumed to be connected to each other via intersatellite links. They are connected to the end user either directly or through gateways to other networks. Frequency reuse, circuit switching, packet switching, call handoff, and routing for these systems are discussed by analogy with terrestrial cellular (mobile radio) telecommunication systems.
di, L.; Yang, W.; Bai, Y.
Remote sensing is one of the major methods for collecting geospatial data. Hugh amount of remote sensing data has been collected by space agencies and private companies around the world. For example, NASA's Earth Observing System (EOS) is generating more than 3 Tb of remote sensing data per day. The data collected by EOS are processed, distributed, archived, and managed by the EOS Data and Information System (EOSDIS). Currently, EOSDIS is managing several petabytes of data. All of those data are not only valuable for global change research, but also useful for local and regional application and decision makings. How to make the data easily accessible to and usable by the user community is one of key issues for realizing the full potential of these valuable datasets. In the past several years, the Open Geospatial Consortium (OGC) has developed several interoperability protocols aiming at making geospatial data easily accessible to and usable by the user community through Internet. The protocols particularly relevant to the discovery, access, and integration of multi-source satellite remote sensing data are the Catalog Service for Web (CS/W) and Web Coverage Services (WCS) Specifications. The OGC CS/W specifies the interfaces, HTTP protocol bindings, and a framework for defining application profiles required to publish and access digital catalogues of metadata for geographic data, services, and related resource information. The OGC WCS specification defines the interfaces between web-based clients and servers for accessing on-line multi-dimensional, multi-temporal geospatial coverage in an interoperable way. Based on definitions by OGC and ISO 19123, coverage data include all remote sensing images as well as gridded model outputs. The Laboratory for Advanced Information Technology and Standards (LAITS), George Mason University, has been working on developing and implementing OGC specifications for better serving NASA Earth science data to the user community for many
Skoglund, S. K.; Weathers, K. C.; Norouzi, H.; Prakash, S.; Ewing, H. A.
Many northern temperate freshwater lakes are freezing over later and thawing earlier. This shift in timing, and the resulting shorter duration of seasonal ice cover, is expected to impact ecological processes, negatively affecting aquatic species and the quality of water we drink. Long-term, direct observations have been used to analyze changes in ice phenology, but those data are sparse relative to the number of lakes affected. Here we develop a model to utilize remote sensing data in approximating the dates of ice-on and ice-off for many years over a variety of lakes. Day and night surface temperatures from MODIS (Moderate Resolution Imaging Spectroradiometer) Aqua and Terra (MYD11A1 and MOD11A1 data products) for 2002-2017 were utilized in combination with observed ice-on and ice-off dates of Lake Auburn, Maine, to determine the ability of MODIS data to match ground-based observations. A moving average served to interpolate MODIS temperature data to fill data gaps from cloudy days. The nighttime data were used for ice-off, and the daytime measurements were used for ice-on predictions to avoid fluctuations between day and night ice/water status. The 0˚C intercepts of those data were used to mark approximate days of ice-on or ice-off. This revealed that approximations for ice-off dates were satisfactory (average ±8.2 days) for Lake Auburn as well as for Lake Sunapee, New Hampshire (average ±8.1 days), while approximations for Lake Auburn ice-on were less accurate and showed consistently earlier-than-observed ice-on dates (average -33.8 days). The comparison of observed and remotely sensed Lake Auburn ice cover duration showed relative agreement with a correlation coefficient of 0.46. Other remote sensing observations, such as the new GOES-R satellite, and further exploration of the ice formation process can improve ice-on approximation methods. The model shows promise for estimating ice-on, ice-off, and ice cover duration for northern temperate lakes.
Lopez Valencia, Oliver Miguel
in terrestrial water storage depletion within the Arabian Peninsula and explore its relation to increased agricultural activity in the region using satellite data. Next, we evaluate a number of large-scale remote sensing-based evaporation models, giving insight
P R Renosh
Full Text Available Satellite remote sensing observations allow the ocean surface to be sampled synoptically over large spatio-temporal scales. The images provided from visible and thermal infrared satellite observations are widely used in physical, biological, and ecological oceanography. The present work proposes a method to understand the multi-scaling properties of satellite products such as the Chlorophyll-a (Chl-a, and the Sea Surface Temperature (SST, rarely studied. The specific objectives of this study are to show how the small scale heterogeneities of satellite images can be characterised using tools borrowed from the fields of turbulence. For that purpose, we show how the structure function, which is classically used in the frame of scaling time series analysis, can be used also in 2D. The main advantage of this method is that it can be applied to process images which have missing data. Based on both simulated and real images, we demonstrate that coarse-graining (CG of a gradient modulus transform of the original image does not provide correct scaling exponents. We show, using a fractional Brownian simulation in 2D, that the structure function (SF can be used with randomly sampled couple of points, and verify that 1 million of couple of points provides enough statistics.
An airborne surveillance program has been conducted over the Belgian part of the North Sea since 1991. The role of the program is to detect infringements on the Marpol Convention via remote sensing, and to take legal action against polluters through the use of recorded observations. Although Belgium has a restricted sea area of about 3,500 km with no fixed offshore oil installations, a pollution risk is constantly present due to 2 dense traffic separation schemes close to the shoreline. The Belgian marine areas and adjacent waters are regularly scanned with a Side Looking Airborne Radar (SLAR) on board a remote sensing aircraft. This paper describes an evaluation trial that the Belgian Management Unit of the North Sea Mathematical Models (MUMM) joined in 2004, together with various agencies from the United Kingdom, Germany and the Netherlands. The trial consists of a cost-sharing satellite service for oil detection with ENVISAT ASAR data. The trial was co-funded by the European Space Agency (ESA) and run by Kongsberg Satellite Services. MUMM's objective was to evaluate the effectiveness and operational character of satellite services for detecting oil spills at sea. The results of the 3 month trial have indicated that aerial remote sensing for the detection of illegal oil discharges at sea increases the chances of catching polluters more efficiently, with improved chances of evidence collecting. It was concluded that when various services are integrated and strict operational conditions are met, satellite services may prove to be valuable in restricted, very densely navigated national waters that are easily reached by airborne means. 12 refs., 8 tabs., 3 figs
Knowledge of the environment has grown to such an extent that information technology (IT) is essential to make sense of the available data. An example of this is remote sensing by satellite. In recent years this field has grown in importance and remote sensing is used for a range of uses including the automatic survey of wheat yields in North…
Kettner, A. J.; Brakenridge, G. R.; van Praag, E.; de Groeve, T.; Slayback, D. A.; Cohen, S.
In collaboration with NASA Goddard Spaceflight Center and the European Commission Joint Research Centre, the Dartmouth Flood Observatory (DFO) daily measures and distributes: 1) river discharges, and 2) near real-time flood extents with a global coverage. Satellite-based passive microwave sensors and hydrological modeling are utilized to establish 'remote-sensing based discharge stations', and observed time series cover 1998 to the present. The advantages over in-situ gauged discharges are: a) easy access to remote or due to political reasons isolated locations, b) relatively low maintenance costs to maintain a continuous observational record, and c) the capability to obtain measurements during floods, hazardous conditions that often impair or destroy in-situ stations. Two MODIS instruments aboard the NASA Terra and Aqua satellites provide global flood extent coverage at a spatial resolution of 250m. Cloud cover hampers flood extent detection; therefore we ingest 6 images (the Terra and Aqua images of each day, for three days), in combination with a cloud shadow filter, to provide daily global flood extent updates. The Flood Observatory has always made it a high priority to visualize and share its data and products through its website. Recent collaborative efforts with e.g. GeoSUR have enhanced accessibility of DFO data. A web map service has been implemented to automatically disseminate geo-referenced flood extent products into client-side GIS software. For example, for Latin America and the Caribbean region, the GeoSUR portal now displays current flood extent maps, which can be integrated and visualized with other relevant geographical data. Furthermore, the flood state of satellite-observed river discharge sites are displayed through the portal as well. Additional efforts include implementing Open Geospatial Consortium (OGC) standards to incorporate Water Markup Language (WaterML) data exchange mechanisms to further facilitate the distribution of the satellite
Engel, J. M.; Polling, D.; Ustamujic, F.; Yaldiz, R.; et al.
(SPoTS) supplying other satellites with energy. SPoTS is due to be commercially viable and operative in 2020. of Technology designed the SPoTS during a full-time design period of six weeks as a third year final project. The team, organized according to the principles of systems engineering, first conducted a literature study on space wireless energy transfer to select the most suitable candidates for use on the SPoTS. After that, several different system concepts have been generated and evaluated, the most promising concept being worked out in greater detail. km altitude. Each SPoTS satellite has a 50m diameter inflatable solar collector that focuses all received sunlight. Then, the received sunlight is further redirected by means of four pointing mirrors toward four individual customer satellites. A market-analysis study showed, that providing power to geo-stationary communication satellites during their eclipse would be most beneficial. At arrival at geo-stationary orbit, the focused beam has expended to such an extent that its density equals one solar flux. This means that customer satellites can continue to use their regular solar arrays during their eclipse for power generation, resulting in a satellite battery mass reduction. the customer satellites in geo-stationary orbit, the transmitted energy beams needs to be pointed with very high accuracy. Computations showed that for this degree of accuracy, sensors are needed, which are not mainstream nowadays. Therefore further research must be conducted in this area in order to make these high-accuracy-pointing systems commercially attractive for use on the SPoTS satellites around 2020. Total 20-year system lifetime cost for 18 SPoT satellites are estimated at approximately USD 6 billion [FY2001]. In order to compete with traditional battery-based satellite power systems or possible ground based wireless power transfer systems the price per kWh for the customer must be significantly lower than the present one
Johnson, D. M.; Dorn, M. F.; Crawford, C.
Since the dawn of earth observation imagery, particularly from systems like Landsat and the Advanced Very High Resolution Radiometer, there has been an overarching desire to regionally estimate crop production remotely. Research efforts integrating space-based imagery into yield models to achieve this need have indeed paralleled these systems through the years, yet development of a truly useful crop production monitoring system has been arguably mediocre in coming. As a result, relatively few organizations have yet to operationalize the concept, and this is most acute in regions of the globe where there are not even alternative sources of crop production data being collected. However, the National Agricultural Statistics Service (NASS) has continued to push for this type of data source as a means to complement its long-standing, traditional crop production survey efforts which are financially costly to the government and create undue respondent burden on farmers. Corn and soybeans, the two largest field crops in the United States, have been the focus of satellite-based production monitoring by NASS for the past decade. Data from the Moderate Resolution Imaging Spectroradiometer (MODIS) has been seen as the most pragmatic input source for modeling yields primarily based on its daily revisit capabilities and reasonable ground sample resolution. The research methods presented here will be broad but provides a summary of what is useful and adoptable with satellite imagery in terms of crop yield estimation. Corn and soybeans will be of particular focus but other major staple crops like wheat and rice will also be presented. NASS will demonstrate that while MODIS provides a slew of vegetation related products, the traditional normalized difference vegetation index (NDVI) is still ideal. Results using land surface temperature products, also generated from MODIS, will also be shown. Beyond the MODIS data itself, NASS research has also focused efforts on understanding a
In the past 20+ years, NASA Goddard Space Flight Center (GSFC) has successfully developed and flown lidars for mapping of Mars, the Earth, Mercury and the Moon. As laser and electro-optics technologies expand and mature, more sophisticated instruments that once were thought to be too complicated for space are being considered and developed. We will present progress on several new, space-based laser instruments that are being developed at GSFC. These include lidars for remote sensing of carbon dioxide and methane on Earth for carbon cycle and global climate change; sodium resonance fluorescence lidar to measure environmental parameters of the middle and upper atmosphere on Earth and Mars and a wind lidar for Mars orbit; in situ laser instruments include remote and in-situ measurements of the magnetic fields; and a time-of-flight mass spectrometer to study the diversity and structure of nonvolatile organics in solid samples on missions to outer planetary satellites and small bodies.
Full Text Available An autonomous remote clock control system is proposed to provide time synchronization and frequency syntonization for satellite to satellite or ground to satellite time transfer, with the system comprising on-board voltage controlled oven controlled crystal oscillators (VC-OCXOs that are disciplined to a remote master atomic clock or oscillator. The synchronization loop aims to provide autonomous operation over extended periods, be widely applicable to a variety of scenarios and robust. A new architecture comprising the use of frequency division duplex (FDD, synchronous time division (STDD duplex and code division multiple access (CDMA with a centralized topology is employed. This new design utilizes dual one-way ranging methods to precisely measure the clock error, adopts least square (LS methods to predict the clock error and employs a third-order phase lock loop (PLL to generate the voltage control signal. A general functional model for this system is proposed and the error sources and delays that affect the time synchronization are discussed. Related algorithms for estimating and correcting these errors are also proposed. The performance of the proposed system is simulated and guidance for selecting the clock is provided.
Li, Tingting; Guo, Hongxiang; Wang, Cen; Wu, Jian
We propose a novel time slot based optical burst switching (OBS) architecture for GEO/LEO based satellite backbone network. This architecture can provide high speed data transmission rate and high switching capacity . Furthermore, we design the control plane of this optical satellite backbone network. The software defined network (SDN) and network slice (NS) technologies are introduced. Under the properly designed control mechanism, this backbone network is flexible to support various services with diverse transmission requirements. Additionally, the LEO access and handoff management in this network is also discussed.
This paper introduces a remote data acquisition system based on MC68HC908GP32 and MSM7512B, which can accomplish remote data communications on telephone network, and realize remote data acquisition. (authors)
Priede, Imants G.
currents, fronts and eddies, which are often the focus of high biological productivity. Direct tracking of animals using satellite-based systems has helped resolve the biological function of such features and indeed animals instrumented in this way have helped the study of such features in three dimensions, including depths beyond the reach of conventional satellite remote sensing. Patterns of surface productivity detected by satellite remote sensing are reflected in deep sea life on the sea floor at abyssal depths >3,000 m. Satellite remote sensing has played a major role in overcoming the problems of large spatial scales and variability in ocean dynamics and is now an essential tool for monitoring global change.
Chen, Xuan; Qi, Wenwen; Xu, Peng
Utilizing the mathematical model of the orbit mechanics, the orbit prediction is to forecast the space target's orbit information of a certain time based on the orbit of the initial moment. The proper satellite radiometric calibration and calibration orbit prediction process are introduced briefly. On the basis of the research of the calibration space position design method and the radiative transfer model, an orbit prediction method for proper satellite radiometric calibration is proposed to select the appropriate calibration arc for the remote sensor and to predict the orbit information of the proper satellite and the remote sensor. By analyzing the orbit constraint of the proper satellite calibration, the GF-1solar synchronous orbit is chose as the proper satellite orbit in order to simulate the calibration visible durance for different satellites to be calibrated. The results of simulation and analysis provide the basis for the improvement of the radiometric calibration accuracy of the satellite remote sensor, which lays the foundation for the high precision and high frequency radiometric calibration.
Using the supervised classification technique, both simulated and empirical satellite remote sensing data are used to train and test the Gaussian mixture model algorithm. For the purpose of validating the experiment, the resulting classified satellite image is compared with the ground truth data. For the simulated modelling, ...
Trinh, R. C.; Holt, B.; Gierach, M.
Coastal pollution poses a major health and environmental hazard, not only for beach goers and coastal communities but for marine organisms as well. Stormwater runoff is the largest source of environmental pollution in coastal waters of the Southern California Bight (SCB) and is of great concern in increasingly urbanized areas. Buoyant wastewater plumes also pose a marine environmental risk. In this study we provide a comprehensive overview of satellite remote sensing capabilities in detecting buoyant coastal pollutants in the form of stormwater runoff and wastewater effluent. The SCB is the final destination of four major urban rivers that act as channels for runoff and pollution during and after rainstorms. We analyzed and compared sea surface roughness data from various Synthetic Aperture Radar (SAR) instruments to ocean color data from the Moderate Imaging System (MODIS) sensor on board the Aqua satellite and correlated the results with existing environmental data in order to create a climatology of naturally occurring stormwater plumes in coastal waters after rain events, from 1992 to 2014 from four major rivers in the area. Heat maps of the primary extent of stormwater plumes were constructed to specify areas that may be subject to the greatest risk of coastal contamination. In conjunction with our efforts to monitor coastal pollution and validate the abilities of satellite remote sensing, a recent Fall 2015 wastewater diversion from the City of Los Angeles Hyperion Treatment Plant (HTP) provided the opportunity to apply these remote sensing methodologies of plume detection to wastewater. During maintenance of their 5-mile long outfall pipe, wastewater is diverted to a shorter outfall pipe that terminates 1-mile offshore and in shallower waters. Sea surface temperature (SST), chlorophyll-a (chl-a) fluorescence, remote sensing reflectance and particulate backscatter signatures were analyzed from MODIS. Terra-ASTER and Landsat-8 thermal infrared data were also
Full Text Available The high resolution satellite with the longer focal length and the larger aperture has been widely used in georeferencing of the observed scene in recent years. The consistent end to end model of high resolution remote sensing satellite geometric chain is presented, which consists of the scene, the three line array camera, the platform including attitude and position information, the time system and the processing algorithm. The integrated design of the camera and the star tracker is considered and the simulation method of the geolocation accuracy is put forward by introduce the new index of the angle between the camera and the star tracker. The model is validated by the geolocation accuracy simulation according to the test method of the ZY-3 satellite imagery rigorously. The simulation results show that the geolocation accuracy is within 25m, which is highly consistent with the test results. The geolocation accuracy can be improved about 7 m by the integrated design. The model combined with the simulation method is applicable to the geolocation accuracy estimate before the satellite launching.
The commercialization of the LANDSAT Satellites, remote sensing research and development as applied to the Earth and its atmosphere as studied by NASA and NOAA is presented. Major gaps in the knowledge of the Earth and its atmosphere are identified and a series of space based measurement objectives are derived. The near-term space observations programs of the United States and other countries are detailed. The start is presented of the planning process to develop an integrated national program for research and development in Earth remote sensing for the remainder of this century and the many existing and proposed satellite and sensor systems that the program may include are described.
Volkova, A.; Gibbens, P. W.
There is a growing demand for unmanned aerial systems as autonomous surveillance, exploration and remote sensing solutions. Among the key concerns for robust operation of these systems is the need to reliably navigate the environment without reliance on global navigation satellite system (GNSS). This is of particular concern in Defence circles, but is also a major safety issue for commercial operations. In these circumstances, the aircraft needs to navigate relying only on information from on-board passive sensors such as digital cameras. An autonomous feature-based visual system presented in this work offers a novel integral approach to the modelling and registration of visual features that responds to the specific needs of the navigation system. It detects visual features from Google Earth* build a feature database. The same algorithm then detects features in an on-board cameras video stream. On one level this serves to localise the vehicle relative to the environment using Simultaneous Localisation and Mapping (SLAM). On a second level it correlates them with the database to localise the vehicle with respect to the inertial frame. The performance of the presented visual navigation system was compared using the satellite imagery from different years. Based on comparison results, an analysis of the effects of seasonal, structural and qualitative changes of the imagery source on the performance of the navigation algorithm is presented. * The algorithm is independent of the source of satellite imagery and another provider can be used
Full Text Available Saliency gives the way as humans see any image and saliency based segmentation can be eventually helpful in Psychovisual image interpretation. Keeping this in view few saliency models are used along with segmentation algorithm and only the salient segments from image have been extracted. The work is carried out for terrestrial images as well as for satellite images. The methodology used in this work extracts those segments from segmented image which are having higher or equal saliency value than a threshold value. Salient and non salient regions of image become foreground and background respectively and thus image gets separated. For carrying out this work a dataset of terrestrial images and Worldview 2 satellite images (sample data are used. Results show that those saliency models which works better for terrestrial images are not good enough for satellite image in terms of foreground and background separation. Foreground and background separation in terrestrial images is based on salient objects visible on the images whereas in satellite images this separation is based on salient area rather than salient objects.
Full Text Available Chemical release disasters have serious consequences, disrupting ecosystems, society, and causing significant loss of life. Mitigating the destructive impacts relies on identification and mapping, monitoring, and trajectory forecasting. Improvements in sensor capabilities are enabling airborne and spacebased remote sensing to support response activities. Key applications are improving transport models in complex terrain and improved disaster response.Chemical release disasters have serious consequences, disrupting ecosystems, society, and causing significant loss of life. Mitigating the destructive impacts relies on identification and mapping, monitoring, and trajectory forecasting. Improvements in sensor capabilities are enabling airborne and space-based remote sensing to support response activities. Key applications are improving transport models in complex terrain and improved disaster response.Understanding urban atmospheric transport in the Los Angeles Basin, where topographic influences on transport patterns are significant, was improved by leveraging the Aliso Canyon leak as an atmospheric tracer. Plume characterization data was collected by the AutoMObile trace Gas (AMOG Surveyor, a commuter car modified for science. Mobile surface in situ CH4 and winds were measured by AMOG Surveyor under Santa Ana conditions to estimate an emission rate of 365±30% Gg yr-1. Vertical profiles were collected by AMOG Surveyor by leveraging local topography for vertical profiling to identify the planetary boundary layer at ~700 m. Topography significantly constrained plume dispersion by up to a factor of two. The observed plume trajectory was used to validate satellite aerosol optical depth-inferred atmospheric transport, which suggested the plume first was driven offshore, but then veered back towards land. Numerical long-range transport model predictions confirm this interpretation. This study demonstrated a novel application of satellite aerosol remote
Simonsen, Sebastian Bjerregaard; Barletta, Valentina Roberta; Forsberg, René
IS hamper in situ observations. Here, we evaluate available data from remote sensing and find a drainage basin in rapid change. An analysis of data from the Gravity Recovery and Climate Experiment (GRACE) satellites shows a mean seasonal freshwater flux into Godthåbsfjord of 18.2 ± 1.2 Gt, in addition......, from various remote-sensing data sets, estimate the freshwater flux from the GrIS into a specific fjord system, the Godthåbsfjord, in southwest Greenland. The area of the GrIS draining into Godthåbsfjord covers approximately 36,700 km2. The large areal extent and the multiple outlets from the Gr...... to an imbalance in the mass balance of the drainage basin from 2003 to 2013 of 14.4 ± 0.2 Gt year−1. Altimetry data from air and spaceborne missions also suggest rapid changes in the outlet glacier dynamics. We find that only applying data from the Ice, Cloud, and land Elevation Satellite (ICESat) mission...
Otto, C; Pipe, A
The purpose of this investigation was to demonstrate the potential of remote, mobile telemedicine during a four-week, high-altitude mountaineering expedition to Mount Logan, Canada's highest summit. Using a mobile satellite terminal and a laptop computer (both powered by a photovoltaic solar panel), ECG tracings and blood pressure measurements, in addition to colour images, short-segment video and audio clips were transmitted during the course of the ascent. The data were transmitted via a mobile communications satellite to a ground station in Ottawa, a distance of over 4000 km. The data were then transferred to the public switched data network and delivered to the University of Ottawa Heart Institute for analysis. Similarly, data were transmitted from the ground station to the expedition team on Mount Logan throughout the ascent. Using this technique, medical diagnosis and emergency care can be facilitated in extreme and isolated locations lacking a telecommunications infrastructure. Such technology has applications in developing countries, disaster response efforts, remote civilian and military operations, and in space operations.
Zhang, Xueyang; Xiang, Junhua
Moving object detection in video satellite image is studied. A detection algorithm based on deep learning is proposed. The small scale characteristics of remote sensing video objects are analyzed. Firstly, background subtraction algorithm of adaptive Gauss mixture model is used to generate region proposals. Then the objects in region proposals are classified via the deep convolutional neural network. Thus moving objects of interest are detected combined with prior information of sub-satellite point. The deep convolution neural network employs a 21-layer residual convolutional neural network, and trains the network parameters by transfer learning. Experimental results about video from Tiantuo-2 satellite demonstrate the effectiveness of the algorithm.
Larsen, Jesper Abildgaard; Mortensen, Hans Peter; Nielsen, Jens Frederik Dalsgaard
For a few years now, there has been a high interest in monitoring the global ship traffic from space. A few satellite, capable of listening for ship borne AIS transponders have already been launched, and soon the AAUSAT3, carrying two different types of AIS receivers will also be launched. One...... of the AIS receivers onboard AAUSAT3 is an SDR based AIS receiver. This paper serves to describe the background of the AIS system, and how the SDR based receiver has been integrated into the AAUSAT3 satellite. Amongst some of the benefits of using an SDR based receiver is, that due to its versatility, new...... detection algorithms are easily deployed, and it is easily adapted the new proposed AIS transmission channels....
Mohammed El Amin, Arabi; Liu, Qingjie; Wang, Yunhong
With the popular use of high resolution remote sensing (HRRS) satellite images, a huge research efforts have been placed on change detection (CD) problem. An effective feature selection method can significantly boost the final result. While hand-designed features have proven difficulties to design features that effectively capture high and mid-level representations, the recent developments in machine learning (Deep Learning) omit this problem by learning hierarchical representation in an unsupervised manner directly from data without human intervention. In this letter, we propose approaching the change detection problem from a feature learning perspective. A novel deep Convolutional Neural Networks (CNN) features based HR satellite images change detection method is proposed. The main guideline is to produce a change detection map directly from two images using a pretrained CNN. This method can omit the limited performance of hand-crafted features. Firstly, CNN features are extracted through different convolutional layers. Then, a concatenation step is evaluated after an normalization step, resulting in a unique higher dimensional feature map. Finally, a change map was computed using pixel-wise Euclidean distance. Our method has been validated on real bitemporal HRRS satellite images according to qualitative and quantitative analyses. The results obtained confirm the interest of the proposed method.
Full Text Available An object-based verification approach is employed to assess the performance of the commonly used high-resolution satellite precipitation products: Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN, Climate Prediction center MORPHing technique (CMORPH, and Tropical Rainfall Measurement Mission (TRMM Multi-Satellite Precipitation Analysis (TMPA 3B42RT. The evaluation of the satellite precipitation products focuses on the skill of depicting the geometric features of the localized precipitation areas. Seasonal variability of the performances of these products against the ground observations is investigated through the examples of warm and cold seasons. It is found that PERSIANN is capable of depicting the orientation of the localized precipitation areas in both seasons. CMORPH has the ability to capture the sizes of the localized precipitation areas and performs the best in the overall assessment for both seasons. 3B42RT is capable of depicting the location of the precipitation areas for both seasons. In addition, all of the products perform better on capturing the sizes and centroids of precipitation areas in the warm season than in the cold season, while they perform better on depicting the intersection area and orientation in the cold season than in the warm season. These products are more skillful on correctly detecting the localized precipitation areas against the observations in the warm season than in the cold season.
Accurate ground-based remotely sensed microphysical and optical properties of liquid water clouds are essential references to validate satellite-observed cloud properties and to improve cloud parameterizations in weather and climate models. This requires the evaluation of algorithms for retrieval of
Yuichi Sarusawa; Kohei Arai
Regression analysis based method for turbidity and ocean current velocity estimation with remote sensing satellite data is proposed. Through regressive analysis with MODIS data and measured data of turbidity and ocean current velocity, regressive equation which allows estimation of turbidity and ocean current velocity is obtained. With the regressive equation as well as long term MODIS data, turbidity and ocean current velocity trends in Ariake Sea area are clarified. It is also confirmed tha...
Minor, Jody L.; Kauffman, William J. (Technical Monitor)
Satellite contamination continues to be a design problem that engineers must take into account when developing new satellites. To help with this issue, NASA's Space Environments and Effects (SEE) Program funded the development of the Satellite Contamination and Materials Outgassing Knowledge base. This engineering tool brings together in one location information about the outgassing properties of aerospace materials based upon ground-testing data, the effects of outgassing that has been observed during flight and measurements of the contamination environment by on-orbit instruments. The knowledge base contains information using the ASTM Standard E- 1559 and also consolidates data from missions using quartz-crystal microbalances (QCM's). The data contained in the knowledge base was shared with NASA by government agencies and industry in the US and international space agencies as well. The term 'knowledgebase' was used because so much information and capability was brought together in one comprehensive engineering design tool. It is the SEE Program's intent to continually add additional material contamination data as it becomes available - creating a dynamic tool whose value to the user is ever increasing. The SEE Program firmly believes that NASA, and ultimately the entire contamination user community, will greatly benefit from this new engineering tool and highly encourages the community to not only use the tool but add data to it as well.
Saul, Peter D.
General practitioners' access to remote data bases using microcomputers is increasing, making even the most obscure information readily available. Some of the systems available to general practitioners in the UK are described and the methods of access are outlined. General practitioners should be aware of the advances in technology; data bases are increasing in size, the cost of access is falling and their use is becoming easier.
Umar, M.; Rhoads, Bruce L.; Greenberg, Jonathan A.
Although past work has noted that contrasts in turbidity often are detectable on remotely sensed images of rivers downstream from confluences, no systematic methodology has been developed for assessing mixing over distance of confluent flows with differing surficial suspended sediment concentrations (SSSC). In contrast to field measurements of mixing below confluences, satellite remote-sensing can provide detailed information on spatial distributions of SSSC over long distances. This paper presents a methodology that uses remote-sensing data to estimate spatial patterns of SSSC downstream of confluences along large rivers and to determine changes in the amount of mixing over distance from confluences. The method develops a calibrated Random Forest (RF) model by relating training SSSC data from river gaging stations to derived spectral indices for the pixels corresponding to gaging-station locations. The calibrated model is then used to predict SSSC values for every river pixel in a remotely sensed image, which provides the basis for mapping of spatial variability in SSSCs along the river. The pixel data are used to estimate average surficial values of SSSC at cross sections spaced uniformly along the river. Based on the cross-section data, a mixing metric is computed for each cross section. The spatial pattern of change in this metric over distance can be used to define rates and length scales of surficial mixing of suspended sediment downstream of a confluence. This type of information is useful for exploring the potential influence of various controlling factors on mixing downstream of confluences, for evaluating how mixing in a river system varies over time and space, and for determining how these variations influence water quality and ecological conditions along the river.
Liao, Sheng-Kai; Yong, Hai-Lin; Liu, Chang; Shentu, Guo-Liang; Li, Dong-Dong; Lin, Jin; Dai, Hui; Zhao, Shuang-Qiang; Li, Bo; Guan, Jian-Yu; Chen, Wei; Gong, Yun-Hong; Li, Yang; Lin, Ze-Hong; Pan, Ge-Sheng
Satellite based quantum communication has been proven as a feasible way to achieve global scale quantum communication network. Very recently, a low-Earth-orbit (LEO) satellite has been launched for this purpose. However, with a single satellite, it takes an inefficient 3-day period to provide the worldwide connectivity. On the other hand, similar to how the Iridium system functions in classic communication, satellite constellation (SC) composed of many quantum satellites, could provide global...
Leifer, Ira; Lehr, William J.; Simecek-Beatty, Debra; Bradley, Eliza; Clark, Roger N.; Dennison, Philip E.; Hu, Yongxiang; Matheson, Scott; Jones, Cathleen E; Holt, Benjamin; Reif, Molly; Roberts, Dar A.; Svejkovsky, Jan; Swayze, Gregg A.; Wozencraft, Jennifer M.
The vast and persistent Deepwater Horizon (DWH) spill challenged response capabilities, which required accurate, quantitative oil assessment at synoptic and operational scales. Although experienced observers are a spill response's mainstay, few trained observers and confounding factors including weather, oil emulsification, and scene illumination geometry present challenges. DWH spill and impact monitoring was aided by extensive airborne and spaceborne passive and active remote sensing.Oil slick thickness and oil-to-water emulsion ratios are key spill response parameters for containment/cleanup and were derived quantitatively for thick (> 0.1 mm) slicks from AVIRIS (Airborne Visible/Infrared Imaging Spectrometer) data using a spectral library approach based on the shape and depth of near infrared spectral absorption features. MODIS (Moderate Resolution Imaging Spectroradiometer) satellite, visible-spectrum broadband data of surface-slick modulation of sunglint reflection allowed extrapolation to the total slick. A multispectral expert system used a neural network approach to provide Rapid Response thickness class maps.Airborne and satellite synthetic aperture radar (SAR) provides synoptic data under all-sky conditions; however, SAR generally cannot discriminate thick (> 100 μm) oil slicks from thin sheens (to 0.1 μm). The UAVSAR's (Uninhabited Aerial Vehicle SAR) significantly greater signal-to-noise ratio and finer spatial resolution allowed successful pattern discrimination related to a combination of oil slick thickness, fractional surface coverage, and emulsification.In situ burning and smoke plumes were studied with AVIRIS and corroborated spaceborne CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation) observations of combustion aerosols. CALIPSO and bathymetry lidar data documented shallow subsurface oil, although ancillary data were required for confirmation.Airborne hyperspectral, thermal infrared data have nighttime and
Wolf, N.; Fuchsgruber, V.; Riembauer, G.; Siegmund, A.
Satellite images have great educational potential for teaching on environmental issues and can promote the motivation of young people to enter careers in natural science and technology. Due to the importance and ubiquity of remote sensing in science, industry and the public, the use of satellite imagery has been included into many school curricular in Germany. However, its implementation into school practice is still hesitant, mainly due to lack of teachers' know-how and education materials that align with the curricula. In the project "Space4Geography" a web-based learning platform is developed with the aim to facilitate the application of satellite imagery in secondary school teaching and to foster effective student learning experiences in geography and other related subjects in an interdisciplinary way. The platform features ten learning modules demonstrating the exemplary application of original high spatial resolution remote sensing data (RapidEye and TerraSAR-X) to examine current environmental issues such as droughts, deforestation and urban sprawl. In this way, students will be introduced into the versatile applications of spaceborne earth observation and geospatial technologies. The integrated web-based remote sensing software "BLIF" equips the students with a toolset to explore, process and analyze the satellite images, thereby fostering the competence of students to work on geographical and environmental questions without requiring prior knowledge of remote sensing. This contribution presents the educational concept of the learning environment and its realization by the example of the learning module "Deforestation of the rainforest in Brasil".
The methods of measuring the existence of erosion and the effects of sand stabilization control systems are described. The mechanics of sand movement, the nature of sand erosion, and the use of satellite data to measure these factors and their surrogates are discussed using the locational and control aspects of aeolian and litoral erosion zones along the sand beach of the Mississippi coast. The aeolian erosion is highlighted due to the redeposition of the sand which causes high cleanup costs, property damage, and safety and health hazards. The areas of differential erosion and the patterns of beach sand movement are illustrated and the use of remote sensing methods to identify the areas of erosion are evaluated.
Labibian, Amir; Bahrami, Amir Hossein; Haghshenas, Javad
This paper presents a computationally efficient algorithm for attitude estimation of remote a sensing satellite. In this study, gyro, magnetometer, sun sensor and star tracker are used in Extended Kalman Filter (EKF) structure for the purpose of Attitude Determination (AD). However, utilizing all of the measurement data simultaneously in EKF structure increases computational burden. Specifically, assuming n observation vectors, an inverse of a 3n×3n matrix is required for gain calculation. In order to solve this problem, an efficient version of EKF, namely Murrell's version, is employed. This method utilizes measurements separately at each sampling time for gain computation. Therefore, an inverse of a 3n×3n matrix is replaced by an inverse of a 3×3 matrix for each measurement vector. Moreover, gyro drifts during the time can reduce the pointing accuracy. Therefore, a calibration algorithm is utilized for estimation of the main gyro parameters.
Maxwell, S.K.; Meliker, J.R.; Goovaerts, P.
In recent years, geographic information systems (GIS) have increasingly been used for reconstructing individual-level exposures to environmental contaminants in epidemiological research. Remotely sensed data can be useful in creating space-time models of environmental measures. The primary advantage of using remotely sensed data is that it allows for study at the local scale (e.g., residential level) without requiring expensive, time-consuming monitoring campaigns. The purpose of our study was to identify how land surface remotely sensed data are currently being used to study the relationship between cancer and environmental contaminants, focusing primarily on agricultural chemical exposure assessment applications. We present the results of a comprehensive literature review of epidemiological research where remotely sensed imagery or land cover maps derived from remotely sensed imagery were applied. We also discuss the strengths and limitations of the most commonly used imagery data (aerial photographs and Landsat satellite imagery) and land cover maps.
Boegh, E.; Dellwik, Ebba; Hahmann, Andrea N.
This paper discusses preliminary remote sensing (MODIS) based hydrological modelling results for the Danish island Sjælland (7330 km2) in relation to project objectives and methodologies of a new research project “Implementing Earth observation and advanced satellite based atmospheric sounders....... For this purpose, a) internal catchment processes will be studied using a Distributed Temperature Sensing (DTS) system, b) Earth observations will be used to upscale from field to regional scales, and c) at the largest scale, satellite based atmospheric sounders and meso-scale climate modelling will be used...
Full Text Available This paper introduces a design scheme of remote monitoring system based on Qt, the scheme of remote monitoring system based on S3C2410 and Qt, with the aid of cross platform development tools Qt and powerful ARM platform design and implementation. The development of remote video surveillance system based on embedded terminal has practical significance and value.
Deschambault, Robert L.; Gregory, Philip R.; Spenler, Stephen; Whalen, Brian A.
The importance of effective ground support for the remote control and data retrieval of a satellite instrument cannot be understated. Problems with ground support may include the need to base personnel at a ground tracking station for extended periods, and the delay between the instrument observation and the processing of the data by the science team. Flexible solutions to such problems in the case of small satellite systems are provided by using low-cost, powerful personal computers and off-the-shelf software for data acquisition and processing, and by using Internet as a communication pathway to enable scientists to view and manipulate satellite data in real time at any ground location. The personal computer based ground support system is illustrated for the case of the cold plasma analyzer flown on the Freja satellite. Commercial software was used as building blocks for writing the ground support equipment software. Several levels of hardware support, including unit tests and development, functional tests, and integration were provided by portable and desktop personal computers. Satellite stations in Saskatchewan and Sweden were linked to the science team via phone lines and Internet, which provided remote control through a central point. These successful strategies will be used on future small satellite space programs.
Campbell, W.J.; Imhoff, M.L.; Robinson, J.; Gunther, F.; Boyd, R.; Anuta, M.
The utility and cost effectiveness of incorporating digitized aircraft and satellite remote sensing data into a geographic information system for facility siting and environmental impact assessments was evaluated. This research focused on the evaluation of several types of multisource remotely sensed data representing a variety of spectral band widths and spatial resolution. High resolution aircraft photography, Landsat MSS, and 7 band Thematic Mapper Simulator (TMS) data were acquired, analyzed, and evaluated for their suitability as input to an operational geographic information system (GIS). 78 references, 59 figures, 74 tables
Daniel, K. C.; Suresh, A.; Paredes Mesa, S.
Lakes are one of the few sources of freshwater used throughout the world but due to human activities, its quality and availability has been decreasing. The drying of lakes is a concerning issue in different communities around the world. This problem can affect jobs and the lives of individuals who use lakes as a source of income, consumption and recreation. Another dilemma that has occurred in lakes is eutrophication which is the buildup of excess nutrients in the lakes caused by runoff. This natural process can lead to anoxic conditions that may have a detrimental impact on surrounding ecosystems. Therefore, causing a devastating impact to economies and human livelihood worldwide. To monitor these issues, satellite data can be used to assess the water quality of different lakes throughout the world. Landsat satellite data from the past 10 years was used to conduct this research. By using the IOP (Inherent Optical Properties) of chlorophyll and suspended solids in the visible spectrum, the presence of algal blooms and sediments was determined. ARCGIS was used to outline the areas of the lakes and obtain reflectance values for quantity and quality assessment. Because there is always a certain amount of contamination in the lake, this research is used to evaluate the condition of the lakes throughout the years. Using the data that we have collected, we are able to understand how the issues addressed can harm civilians seasonally. Key Words: Lakes, Water Quality, Algal Blooms, Eutrophication, Remote Sensing, Satellite DataData Source: Landsat 4, Landsat 5, Landsat 7, Landsat 8
Sowden, M.; Mueller, U.; Blake, D.
The accurate measurements of natural and anthropogenic aerosol particulate matter (PM) is important in managing both environmental and health risks; however, limited monitoring in regional areas hinders accurate quantification. This article provides an overview of the ability of recently launched geostationary earth orbit (GEO) satellites, such as GOES-R (North America) and HIMAWARI (Asia and Oceania), to provide near real-time ground-level PM concentrations (GLCs). The review examines the literature relating to the spatial and temporal resolution required by air quality studies, the removal of cloud and surface effects, the aerosol inversion problem, and the computation of ground-level concentrations rather than columnar aerosol optical depth (AOD). Determining surface PM concentrations using remote sensing is complicated by differentiating intrinsic aerosol properties (size, shape, composition, and quantity) from extrinsic signal intensities, particularly as the number of unknown intrinsic parameters exceeds the number of known extrinsic measurements. The review confirms that development of GEO satellite products has led to improvements in the use of coupled products such as GEOS-CHEM, aerosol types have consolidated on model species rather than prior descriptive classifications, and forward radiative transfer models have led to a better understanding of predictive spectra interdependencies across different aerosol types, despite fewer wavelength bands. However, it is apparent that the aerosol inversion problem remains challenging because there are limited wavelength bands for characterising localised mineralogy. The review finds that the frequency of GEO satellite data exceeds the temporal resolution required for air quality studies, but the spatial resolution is too coarse for localised air quality studies. Continual monitoring necessitates using the less sensitive thermal infra-red bands, which also reduce surface absorption effects. However, given the
AghaKouchak, Amir; Nakhjiri, Navid
Reliable drought monitoring requires long-term and continuous precipitation data. High resolution satellite measurements provide valuable precipitation information on a quasi-global scale. However, their short lengths of records limit their applications in drought monitoring. In addition to this limitation, long-term low resolution satellite-based gauge-adjusted data sets such as the Global Precipitation Climatology Project (GPCP) one are not available in near real-time form for timely drought monitoring. This study bridges the gap between low resolution long-term satellite gauge-adjusted data and the emerging high resolution satellite precipitation data sets to create a long-term climate data record of droughts. To accomplish this, a Bayesian correction algorithm is used to combine GPCP data with real-time satellite precipitation data sets for drought monitoring and analysis. The results showed that the combined data sets after the Bayesian correction were a significant improvement compared to the uncorrected data. Furthermore, several recent major droughts such as the 2011 Texas, 2010 Amazon and 2010 Horn of Africa droughts were detected in the combined real-time and long-term satellite observations. This highlights the potential application of satellite precipitation data for regional to global drought monitoring. The final product is a real-time data-driven satellite-based standardized precipitation index that can be used for drought monitoring especially over remote and/or ungauged regions. (letter)
Stemmann, L.; Tintoré, J.; Moneris, S.
The knowledge of future oceanic conditions would have enormous impact on human marine related areas. For such reasons, a number of international efforts are being carried out to obtain reliable and manageable ocean forecasting systems. Among the possible techniques that can be used to estimate the near future states of the ocean, an ocean forecasting system based on satellite imagery is developped through the Satelitte based Ocean ForecasTing project (SOFT). SOFT, established by the European Commission, considers the development of a forecasting system of the ocean space-time variability based on satellite data by using Artificial Intelligence techniques. This system will be merged with numerical simulation approaches, via assimilation techniques, to get a hybrid SOFT-numerical forecasting system of improved performance. The results of the project will provide efficient forecasting of sea-surface temperature structures, currents, dynamic height, and biological activity associated to chlorophyll fields. All these quantities could give valuable information on the planning and management of human activities in marine environments such as navigation, fisheries, pollution control, or coastal management. A detailed identification of present or new needs and potential end-users concerned by such an operational tool is being performed. The project would study solutions adapted to these specific needs.
Picard, R. H; Dewan, E. M; Winick, J. R; O'Neil, R. R
This report describes work carried out under the Air Force Research Laboratory's basic research task in optical remote-sensing signatures, entitled Optical / Infrared Signatures for Space-Based Remote Sensing...
Hasager, Charlotte Bay; Mouche, Alexis; Badger, Merete
-based observations become available. At present preliminary results are obtained using the routine methods. The first step in the process is to retrieve raw SAR data, calibrate the images and use a priori wind direction as input to the geophysical model function. From this process the wind speed maps are produced....... The wind maps are geo-referenced. The second process is the analysis of a series of geo-referenced SAR-based wind maps. Previous research has shown that a relatively large number of images are needed for achieving certain accuracies on mean wind speed, Weibull A and k (scale and shape parameters......Ocean wind maps from satellites are routinely processed both at Risø DTU and CLS based on the European Space Agency Envisat ASAR data. At Risø the a priori wind direction is taken from the atmospheric model NOGAPS (Navel Operational Global Atmospheric Prediction System) provided by the U.S. Navy...
Cooper, Mathew J.; Martin, Randall V.; vanDonkelaar, Aaron; Lamsal, Lok; Brauer, Michael; Brook, Jeffrey R.
Air pollution is a major health hazard that is responsible formillions of annual excess deaths worldwide. Simpleindicators are useful for comparative studies and to asses strends over time. The development of global indicators hasbeen impeded by the lack of ground-based observations in vast regions of the world. Recognition is growing of the need for amultipollutant approach to air quality to better represent human exposure. Here we introduce the prospect of amultipollutant air quality indicator based on observations from satellite remote sensing.
Cook, S.A.; Crowe, R.D.; Roblyer, S.P.; Toffer, H.
The Hanford N Reactor is operated by UNC Nuclear Industries for the Department of Energy for the production of special isotopes and electric energy. The reactor has a unique design in which the equipment such as pumps, turbines, generators and diesel engines are located in separate buildings. This equipment arrangement has led to the conclusion that the most cost-effective implementation of a dedicated vibration monitoring system would be to install a computerized network system in lieu of a single analyzing station. In this approach, semi-autonomous micro processor based data collection stations referred to as satellite stations are located near each concentration of machinery to be monitored. The satellite stations provide near continuous monitoring of the machinery. They are linked to a minicomputer using voice grade telephone circuits and hardware and software specifically designed for network communications. The communications link between the satellite stations and the minicomputer permits data and programs to be transmitted between the units. This paper will describe the satellite station associated with large vertical pumps vibration monitoring. The reactor has four of these pumps to supply tertiary cooling to reactor systems. 4 figs
Ionospheric specification and modeling are now largely based on data provided by active remote sensing with radiowave techniques (ionosondes, incoherent-scatter radars, and satellite beacons). More recently, passive remote sensing techniques have been developed that can be used to monitor quantitatively the spatial distribution of high-latitude E-region ionization. These passive methods depend on the measurement, or inference, of the energy distribution of precipitating kilovolt electrons, the principal source of the nighttime E-region at high latitudes. To validate these techniques, coordinated measurements of the auroral ionosphere have been made with the Chatanika incoherent-scatter radar and a variety of ground-based and spaceborne sensors
New particle formation (NPF) can potentially alter regional climate by increasing aerosol particle (hereafter particle) number concentrations and ultimately cloud condensation nuclei. The large scales on which NPF is manifest indicate potential to use satellite-based (inherently spatially averaged) measurements of atmospheric conditions to diagnose the occurrence of NPF and NPF characteristics. We demonstrate the potential for using satellite-measurements of insolation (UV), trace gas concentrations (sulfur dioxide (SO2), nitrogen dioxide (NO2), ammonia (NH3), formaldehyde (HCHO), ozone (O3)), aerosol optical properties (aerosol optical depth (AOD), Ångström exponent (AE)), and a proxy of biogenic volatile organic compound emissions (leaf area index (LAI), temperature (T)) as predictors for NPF characteristics: formation rates, growth rates, survival probabilities, and ultrafine particle (UFP) concentrations at five locations across North America. NPF at all sites is most frequent in spring, exhibits a one-day autocorrelation, and is associated with low condensational sink (AOD×AE) and HCHO concentrations, and high UV. However, there are important site-to-site variations in NPF frequency and characteristics, and in which of the predictor variables (particularly gas concentrations) significantly contribute to the explanatory power of regression models built to predict those characteristics. This finding may provide a partial explanation for the reported spatia
In national and international economics, geographic information plays a role which is generally acknowledged to be important but which is however, difficult to assess quantitatively, its applications being rather miscellaneous and indirect. Computer graphics and telecommunications increae that importance still more and justify many investments and research into new cartographic forms. As part of its responsibility for participating in the promotion of those developments, by taking into account needs expressed by public or private users, the National Council for Geographic Information (C.N.I.G.) has undertaken a general evaluation of the economic and social utility of geographic information in France. The study involves an estimation of the cost of production and research activities, which are probably about 0.1% of the Cross National Product—similar to many other countries. It also devised a method of estimating "cost/advantage" ratios applicable to these "intangible" benefits. Within that framework, remote sensing emphasizes particular aspects related both to the increase of economic performances in cartographic production and to the advent of new products and new ways of utilization. A review of some significant sectors shows effective earnings of about 10-20%, or even 50% or 100% of the costs, and these are doubtless much greater for the efficacy in the exploitation of products. Finally, many applications, entirely new result from extensions in various fields which would have been impossible without remote sensing: here the "cost advantage" ratio cannot even be compared with previous processes. Studies were undertaken in parallel for defining different types of products derived from satellite imagery, as well as those domains where development effort is required in order to make new advances.
Full Text Available Satellite remote sensing (RS is routinely used for the large-scale monitoring of microphytobenthos (MPB biomass in intertidal mudflats and has greatly improved our knowledge of MPB spatio-temporal variability and its potential drivers. Processes operating on smaller scales however, such as the impact of benthic macrofauna on MPB development, to date remain underinvestigated. In this study, we analysed the influence of wild Crassostrea gigas oyster reefs on MPB biofilm development using multispectral RS. A 30-year time series (1985–2015 combining high-resolution (30 m Landsat and SPOT data was built in order to explore the relationship between C. gigas reefs and MPB spatial distribution and seasonal dynamics, using the normalized difference vegetation index (NDVI. Emphasis was placed on the analysis of a before–after control-impact (BACI experiment designed to assess the effect of oyster killing on the surrounding MPB biofilms. Our RS data reveal that the presence of oyster reefs positively affects MPB biofilm development. Analysis of the historical time series first showed the presence of persistent, highly concentrated MPB patches around oyster reefs. This observation was supported by the BACI experiment which showed that killing the oysters (while leaving the physical reef structure, i.e. oyster shells, intact negatively affected both MPB biofilm biomass and spatial stability around the reef. As such, our results are consistent with the hypothesis of nutrient input as an explanation for the MPB growth-promoting effect of oysters, whereby organic and inorganic matter released through oyster excretion and biodeposition stimulates MPB biomass accumulation. MPB also showed marked seasonal variations in biomass and patch shape, size and degree of aggregation around the oyster reefs. Seasonal variations in biomass, with higher NDVI during spring and autumn, were consistent with those observed on broader scales in other European mudflats. Our
Echappé, Caroline; Gernez, Pierre; Méléder, Vona; Jesus, Bruno; Cognie, Bruno; Decottignies, Priscilla; Sabbe, Koen; Barillé, Laurent
Satellite remote sensing (RS) is routinely used for the large-scale monitoring of microphytobenthos (MPB) biomass in intertidal mudflats and has greatly improved our knowledge of MPB spatio-temporal variability and its potential drivers. Processes operating on smaller scales however, such as the impact of benthic macrofauna on MPB development, to date remain underinvestigated. In this study, we analysed the influence of wild Crassostrea gigas oyster reefs on MPB biofilm development using multispectral RS. A 30-year time series (1985-2015) combining high-resolution (30 m) Landsat and SPOT data was built in order to explore the relationship between C. gigas reefs and MPB spatial distribution and seasonal dynamics, using the normalized difference vegetation index (NDVI). Emphasis was placed on the analysis of a before-after control-impact (BACI) experiment designed to assess the effect of oyster killing on the surrounding MPB biofilms. Our RS data reveal that the presence of oyster reefs positively affects MPB biofilm development. Analysis of the historical time series first showed the presence of persistent, highly concentrated MPB patches around oyster reefs. This observation was supported by the BACI experiment which showed that killing the oysters (while leaving the physical reef structure, i.e. oyster shells, intact) negatively affected both MPB biofilm biomass and spatial stability around the reef. As such, our results are consistent with the hypothesis of nutrient input as an explanation for the MPB growth-promoting effect of oysters, whereby organic and inorganic matter released through oyster excretion and biodeposition stimulates MPB biomass accumulation. MPB also showed marked seasonal variations in biomass and patch shape, size and degree of aggregation around the oyster reefs. Seasonal variations in biomass, with higher NDVI during spring and autumn, were consistent with those observed on broader scales in other European mudflats. Our study provides the
A two phase study was conducted to analyze and develop the requirements for remote operating systems as applied to space based operations for the servicing, maintenance, and repair of satellites. Phase one consisted of the development of servicing requirements to establish design criteria for remote operating systems. Phase two defined preferred system concepts and development plans which met the requirements established in phase one. The specific tasks in phase two were to: (1) identify desirable operational and conceptual approaches for selected mission scenarios; (2) examine the potential impact of remote operating systems incorporated into the design of the space station; (3) address remote operating systems design issues, such as mobility, which are effected by the space station configuration; and (4) define the programmatic approaches for technology development, testing, simulation, and flight demonstration.
Zoran, Maria; Savastru, Roxana; Savastru, Dan; Tautan, Marina; Miclos, Sorin; Cristescu, Luminita; Carstea, Elfrida; Baschir, Laurentiu
Urban systems play a vital role in social and economic development in all countries. Their environmental changes can be investigated on different spatial and temporal scales. Urban and peri-urban environment dynamics is of great interest for future planning and decision making as well as in frame of local and regional changes. Changes in urban land cover include changes in biotic diversity, actual and potential primary productivity, soil quality, runoff, and sedimentation rates, and cannot be well understood without the knowledge of land use change that drives them. The study focuses on the assessment of environmental features changes for Bucharest metropolitan area, Romania by satellite remote sensing and in-situ monitoring data. Rational feature selection from the varieties of spectral channels in the optical wavelengths of electromagnetic spectrum (VIS and NIR) is very important for effective analysis and information extraction of remote sensing data. Based on comprehensively analyses of the spectral characteristics of remote sensing data is possibly to derive environmental changes in urban areas. The information quantity contained in a band is an important parameter in evaluating the band. The deviation and entropy are often used to show information amount. Feature selection is one of the most important steps in recognition and classification of remote sensing images. Therefore, it is necessary to select features before classification. The optimal features are those that can be used to distinguish objects easily and correctly. Three factors—the information quantity of bands, the correlation between bands and the spectral characteristic (e.g. absorption specialty) of classified objects in test area Bucharest have been considered in our study. As, the spectral characteristic of an object is influenced by many factors, being difficult to define optimal feature parameters to distinguish all the objects in a whole area, a method of multi-level feature selection
Full Text Available Landslides are devastating phenomena that cause huge damage around the world. This paper presents a quasi-global landslide model derived using satellite precipitation data, land-use land cover maps, and 250 m topography information. This suggested landslide model is based on the Support Vector Machines (SVM, a machine learning algorithm. The National Aeronautics and Space Administration (NASA Goddard Space Flight Center (GSFC landslide inventory data is used as observations and reference data. In all, 70% of the data are used for model development and training, whereas 30% are used for validation and verification. The results of 100 random subsamples of available landslide observations revealed that the suggested landslide model can predict historical landslides reliably. The average error of 100 iterations of landslide prediction is estimated to be approximately 7%, while approximately 2% false landslide events are observed.
Peach, R. C.; Miller, N.; Lee, M.
Modern mobile communications satellites, such as INMARSAT 3, EMS, and ARTEMIS, use advanced onboard processing to make efficient use of the available L-band spectrum. In all of these cases, high performance surface acoustic wave (SAW) devices are used. SAW filters can provide high selectivity (100-200 kHz transition widths), combined with flat amplitude and linear phase characteristics; their simple construction and radiation hardness also makes them especially suitable for space applications. An overview of the architectures used in the above systems, describing the technologies employed, and the use of bandwidth switchable SAW filtering (BSSF) is given. The tradeoffs to be considered when specifying a SAW based system are analyzed, using both theoretical and experimental data. Empirical rules for estimating SAW filter performance are given. Achievable performance is illustrated using data from the INMARSAT 3 engineering model (EM) processors.
Madry, Scott; Camacho-Lara, Sergio
The first edition of this ground breaking reference work was the most comprehensive reference source available about the key aspects of the satellite applications field. This updated second edition covers the technology, the markets, applications and regulations related to satellite telecommunications, broadcasting and networking—including civilian and military systems; precise satellite navigation and timing networks (i.e. GPS and others); remote sensing and meteorological satellite systems. Created under the auspices of the International Space University based in France, this brand new edition is now expanded to cover new innovative small satellite constellations, new commercial launching systems, innovation in military application satellites and their acquisition, updated appendices, a useful glossary and more.
Dhekne, P.S.; Patil, Jitendra; Kulkarni, Jitendra; Babu, Prasad; Lad, U.C.; Rahurkar, A.G.; Kaura, H.K.
The Web-based technology provides a very powerful communication medium for transmitting effectively multimedia information containing data generated from various sources, which may be in the form of audio, video, text, still or moving images etc. Large number of sophisticated web based software tools are available that can be used to monitor and control distributed electronic instrumentation projects. For example data can be collected online from various smart sensors/instruments such as images from CCD camera, pressure/ humidity sensor, light intensity transducer, smoke detectors etc and uploaded in real time to a central web server. This information can be processed further, to take control action in real time from any remote client, of course with due security care. The web-based technology offers greater flexibility, higher functionality, and high degree of integration providing standardization. Further easy to use standard browser based interface at the client end to monitor, view and control the desired process parameters allow you to cut down the development time and cost to a great extent. A system based on a web client-server approach has been designed and developed at Computer division, BARC and is operational since last year to monitor and control remotely various environmental parameters of distributed computer centers. In this paper we shall discuss details of this system, its current status and additional features which are currently under development. This type of system is typically very useful for Meteorology, Environmental monitoring of Nuclear stations, Radio active labs, Nuclear waste immobilization plants, Medical and Biological research labs., Security surveillance and in many such distributed situations. A brief description of various tools used for this project such as Java, CGI, Java Script, HTML, VBScript, M-JPEG, TCP/IP, UDP, RTP etc. along with their merits/demerits have also been included
Fishman, Jack; Al-Saadi, Jassim A.; Neil, Doreen O.; Creilson, John K.; Severance, Kurt; Thomason, Larry W.; Edwards, David R.
When the first observations of a tropospheric trace gas were obtained in the 1980s, carbon monoxide enhancements from tropical biomass burning dominated the observed features. In 2005, an active remote-sensing system to provide detailed information on the vertical distribution of aerosols and clouds was launched, and again, one of the most imposing features observed was the presence of emissions from tropical biomass burning. This paper presents a brief overview of space-borne observations of the distribution of trace gases and aerosols and how tropical biomass burning, primarily in the Southern Hemisphere, has provided an initially surprising picture of the distribution of these species and how they have evolved from prevailing transport patterns in that hemisphere. We also show how interpretation of these observations has improved significantly as a result of the improved capability of trajectory modeling in recent years and how information from this capability has provided additional insight into previous measurements form satellites. Key words: pollution; biomass burning; aerosols; tropical trace gas emissions; Southern Hemisphere; carbon monoxide.
Suhartono Nurdin; Muzzneena Ahmad Mustapha; Tukimat Lihan; Mazlan Abdul Ghaffar; Muzzneena Ahmad Mustapha; Nurdin, S.
Analysis of relationship between sea surface temperature (SST) and Chlorophyll-a (chl-a) improves our understanding on the variability and productivity of the marine environment, which is important for exploring fishery resources. Monthly level 3 and daily level 1 images of Moderate Resolution Imaging Spectroradiometer Satellite (MODIS) derived SST and chl-a from July 2002 to June 2011 around the archipelagic waters of Spermonde Indonesia were used to investigate the relationship between SST and chl-a and to forecast the potential fishing ground of Rastrelliger kanagurta. The results indicated that there was positive correlation between SST and chl-a (R=0.3, p<0.05). Positive correlation was also found between SST and chl-a with the catch of R. kanagurta (R=0.7, p<0.05). The potential fishing grounds of R. kanagurta were found located along the coast (at accuracy of 76.9 %). This study indicated that, with the integration of remote sensing technology, statistical modeling and geographic information systems (GIS) technique were able to determine the relationship between SST and chl-a and also able to forecast aggregation of R. kanagurta. This may contribute in decision making and reducing search hunting time and cost in fishing activities. (author)
the application of satellite Earth Observation (EO) methods to the analysis of transportation networks. Other geospatial technologies, including geographic information systems (GIS) and the Global Positioning System (GPS), sharply enhance the utility of EO data in identifying potential road hazards and providing an objective basis for allocating resources to reduce their risks. In combination, these powerful information technologies provide substantial public benefits and increased business opportunities to remote sensing value-added firms. departments in rural jurisdictions improve the trafficability of the roads under their management during severe weather. We are developing and testing these methods in the U.S. Southwest, where thousands of kilometers of unimproved and graded dirt roads cross Native American reservations. This generally arid region is nevertheless subject to periodic summer rainstorms and winter snow and ice, creating hazardous conditions for the region's transportation lifelines. Arizona and Southeast Utah, as well as digital terrain models from the U.S. Geological Survey. We have analyzed several risk factors, such as slope, road curvature, and intersections, by means of multi-criteria evaluation (MCE) on both unimproved and improved roads. In partnership with the Hopi Indian Nation in Arizona, we have acquired and analyzed GPS road centerline data and accident data that validate our methodology. hazards along paved and unpaved roads of the American Southwest. They are also transferable to the international settings, particularly in similarly arid climates.
Full Text Available Critical land classification can be analyzed using combination between Top Soil Thickness - Land erosion method, and BRLT methods. Both methods are needed soil erosion data as one of input data. The soil erosion data can be analyzed using USLE and MUSLE methods. The combination of two critical land analyses methods with input soil erosion data from two analyses methods will be produced four combinations of critical land classification. In this research, four of the critical land classification and two soil erosion classification will be analyzed using GIS. The best method to classify critical land will be investigated in this research. The best classified critical land is the classified critical land data is nearest with the field condition. Percentage of vegetation cover (PVC is one of the most important input data in the critical land classification analysis using BRLKT method. This data have 50% weight. PVC condition is classified into five categories i.e. very good, good, fair, poor, and very poor. Each category have score 5, 4, 3, 2, 1 respectively. To analyze this PVC classification, NDVI generated from satellite remote sensing data is used in this research. From the four methods of land critical classification analyses used in this research, critical land classified using BRLKT method with input soil erosion analyzed using method is produced the critical land classification nearest with the critical land condition in the field.
Tsekeridou, Sofia; Tiropanis, Thanassis; Rorris, Dimitris; Constantinos, Makropoulos; Serif, Tacha; Stergioulas, Lampros
Advanced tele-education services provision in remote geographically dispersed user communities (such as agriculture and maritime), based on the specific needs and requirements of such communities, implies significant infrastructural and broadband connectivity requirements for rich media, timely and quality-assured content delivery and interactivity. The solution to broadband access anywhere is provided by satellite-enabled communication infrastructures. This paper aims to present such satelli...
Kai Xu; Guo Zhang; Qingjun Zhang; Deren Li
In studies involving the extraction of surface physical parameters using optical remote sensing satellite imagery, sun-sensor geometry must be known, especially for sensor viewing angles. However, while pixel-by-pixel acquisitions of sensor viewing angles are of critical importance to many studies, currently available algorithms for calculating sensor-viewing angles focus only on the center-point pixel or are complicated and are not well known. Thus, this study aims to provide a simple and ge...
Chen, Junfa; Zhuo, Yong; Liu, Zuguo; Chen, Yanping
To realize the remote operation of the slit lamp microscope for department of ophthalmology consultation, and visual display the real-time status of remote slit lamp microscope, a remote slit lamp microscope consultation system based on B/S structure is designed and implemented. Through framing the slit lamp microscope on the website system, the realtime acquisition and transmission of remote control and image data is realized. The three dimensional model of the slit lamp microscope is established and rendered on the web by using WebGL technology. The practical application results can well show the real-time interactive of the remote consultation system.
Tripp, Howard; Palmer, Phil
Multi-platform swarm/cluster missions are an attractive prospect for improved science return as they provide a natural capability for temporal, spatial and signal separation with further engineering and economic advantages. As spacecraft numbers increase and/or the round-trip communications delay from Earth lengthens, the traditional "remote-control" approach begins to break down. It is therefore essential to push control into space; to make spacecraft more autonomous. An autonomous group of spacecraft requires coordination, but standard terrestrial paradigms such as negotiation, require high levels of inter-spacecraft communication, which is nontrivial in space. This article therefore introduces the principals of stigmergy as a novel method for coordinating a cluster. Stigmergy is an agent-based, behavioural approach that allows for infrequent communication with decisions based on local information. Behaviours are selected dynamically using a genetic algorithm onboard. supervisors/ground stations occasionally adjust parameters and disseminate a "common environment" that is used for local decisions. After outlining the system, an analysis of some crucial parameters such as communications overhead and number of spacecraft is presented to demonstrate scalability. Further scenarios are considered to demonstrate the natural ability to deal with dynamic situations such as the failure of spacecraft, changing mission objectives and responding to sudden bursts of high priority tasks.
Full Text Available Taking advantage of multiple new remote sensing data sources, especially from Chinese satellites, the CropWatch system has expanded the scope of its international analyses through the development of new indicators and an upgraded operational methodology. The approach adopts a hierarchical system covering four spatial levels of detail: global, regional, national (thirty-one key countries including China and “sub-countries” (for the nine largest countries. The thirty-one countries encompass more that 80% of both production and exports of maize, rice, soybean and wheat. The methodology resorts to climatic and remote sensing indicators at different scales. The global patterns of crop environmental growing conditions are first analyzed with indicators for rainfall, temperature, photosynthetically active radiation (PAR as well as potential biomass. At the regional scale, the indicators pay more attention to crops and include Vegetation Health Index (VHI, Vegetation Condition Index (VCI, Cropped Arable Land Fraction (CALF as well as Cropping Intensity (CI. Together, they characterize crop situation, farming intensity and stress. CropWatch carries out detailed crop condition analyses at the national scale with a comprehensive array of variables and indicators. The Normalized Difference Vegetation Index (NDVI, cropped areas and crop conditions are integrated to derive food production estimates. For the nine largest countries, CropWatch zooms into the sub-national units to acquire detailed information on crop condition and production by including new indicators (e.g., Crop type proportion. Based on trend analysis, CropWatch also issues crop production supply outlooks, covering both long-term variations and short-term dynamic changes in key food exporters and importers. The hierarchical approach adopted by CropWatch is the basis of the analyses of climatic and crop conditions assessments published in the quarterly “CropWatch bulletin” which
Y. H. Ahn
Full Text Available With the aim to map and monitor a low-salinity water (LSW plume in the East China Sea (ECS, we developed more robust and proper regional algorithms from large in-situ measurements of apparent and inherent optical properties (i.e. remote sensing reflectance, Rrs, and absorption coefficient of coloured dissolved organic matter, aCDOM determined in ECS and neighboring waters. Using the above data sets, we derived the following relationships between visible Rrs and absorption by CDOM, i.e. Rrs (412/Rrs (555 vs. aCDOM (400 (m−1 and aCDOM (412 (m−1 with a correlation coefficient R2 0.67 greater than those noted for Rrs (443/Rrs (555 and Rrs (490/Rrs (555 vs. aCDOM (400 (m−1 and aCDOM (412 (m−1. Determination of aCDOM (m−1 at 400 nm and 412 nm is particularly necessary to describe its absorption as a function of wavelength λ using a single exponential model in which the spectral slope S as a proxy for CDOM composition is estimated by the ratio of aCDOM at 412 nm and 400 nm and the reference is explained simply by aCDOM at 412 nm. In order to derive salinity from the absorption coefficient of CDOM, in-situ measurements of salinity made in a wide range of water types from dense oceanic to light estuarine/coastal systems were used along with in-situ measurements of aCDOM at 400 nm, 412 nm, 443 nm and 490 nm. The CDOM absorption at 400 nm was better inversely correlated (R2=0.86 with salinity than at 412 nm, 443 nm and 490 nm (R2=0.85–0.66, and this correlation corresponded best with an exponential (R2=0.98 rather than a linear function of salinity measured in a variety of water types from this and other regions. Validation against a discrete in-situ data set showed that empirical algorithms derived from the above relationships could be successfully applied to satellite data over the range of water types for which they have been developed. Thus, we applied these algorithms to a series of SeaWiFS images for the derivation of CDOM and salinity
Shepherd, M.; Santanello, J. A., Jr.
When Explorer 1 launched nearly 60 years ago, it helped usher in a golden age of scientific understanding of arguably the most important planet in our solar system. From its inception NASA and its partners were charged with leveraging the vantagepoint of space to advance knowledge outside and within Earth's atmosphere. Earth is a particularly complex natural system that is increasingly modified by human activities. The hydrological or water cycle is a critical circuit in the Earth system. Its complexity requires novel observations and simulation capability to fully understand it and predict changes. This talk will introduce some of the unique satellite-based observations used for hydroclimate studies. Two specific examples will be presented. The first example explores a relatively new thread of research examining the impact of soil moisture on landfalling and other types of tropical systems. Recent literature suggests that tropical cyclones or large rain-producing systems like the one that caused catastrophic flooding in Louisiana (2016) derive moisture from a "brown ocean" of wet soils or wetlands. The second example summarizes a decade of research on how urbanization has altered the precipitation and land surface hydrology components of the water cycle. With both cases, a multitude of satellite or model-based datesets will be summarized (e.g., TRMM, GPM, SMAP, NLDAS).
Fabrizi, Roberto; Bonafoni, Stefania; Biondi, Riccardo
In this work, the trend of the Urban Heat Island (UHI) of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging...... and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI) during summer months reveals a mean growth in magnitude of 3-4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations. © 2010...... by the authors; licensee MDPI, Basel, Switzerland. Keyword: Thermal pollution,Summer months,Advanced-along track scanning radiometers,Urban heat island,Remote sensing,Canopy layer,Atmospheric temperature,Ground based sensors,Weather information services,Satellite remote sensing,Infra-red sensor,Weather stations...
Full Text Available Remote areas are difficult to access, tend to lack critical infrastructure, are highly susceptible to shocks in the marketplace, and are perceived by industry to possess limited development opportunities. Accordingly a community orientated and territorial approach to development planning in a remote area will be more successful than a top down industry based approach . Given the limitations of being remote, the case study community examined in this research manages and sustains a bird watching tourism product within a global market place. This paper examines how a remotely located community in the Arfak Mountains of West Papua overcomes these difficulties and plans for community based tourism (CBT in their locale.
The development of better agricultural monitoring capabilities is clearly considered as a critical step for strengthening food production information and market transparency thanks to timely information about crop status, crop area and yield forecasts. The documentation of global production will contribute to tackle price volatility by allowing local, national and international operators to make decisions and anticipate market trends with reduced uncertainty. Several operational agricultural monitoring systems are currently operating at national and international scales. Most are based on the methods derived from the pioneering experiences completed some decades ago, and use remote sensing to qualitatively compare one year to the others to estimate the risks of deviation from a normal year. The GEO Agricultural Monitoring Community of Practice described the current monitoring capabilities at the national and global levels. An overall diagram summarized the diverse relationships between satellite EO and agriculture information. There is now a large gap between the current operational large scale systems and the scientific state of the art in crop remote sensing, probably because the latter mainly focused on local studies. The poor availability of suitable in-situ and satellite data over extended areas hampers large scale demonstrations preventing the much needed up scaling research effort. For the cropland extent, this paper reports a recent research achievement using the full ENVISAT MERIS 300 m archive in the context of the ESA Climate Change Initiative. A flexible combination of classification methods depending to the region of the world allows mapping the land cover as well as the global croplands at 300 m for the period 2008 2012. This wall to wall product is then compared with regards to the FP 7-Geoland 2 results obtained using as Landsat-based sampling strategy over the IGADD countries. On the other hand, the vegetation indices and the biophysical variables
The application of satellite images in an oil spill response operation, was discussed. The oil movement and satellite imagery of the Sea Empress spill was described in detail. There were large discrepancies in the predictions by Radarsat satellite imagery and the actual oil movement, and in this instance, the satellite imagery proved to be more of a distraction than a useful tool. It was suggested that the greatest potential for satellite imagery is in detecting smaller releases of oil, such as from illegal tank washings, ballast waters from ships, or operational malfunctions at oil rigs. 4 refs., 10 figs
Regev, Nir; Wulich, Dov
Breathing monitors have become the all-important cornerstone of a wide variety of commercial and personal safety applications, ranging from elderly care to baby monitoring. Many such monitors exist in the market, some, with vital signs monitoring capabilities, but none remote. This paper presents a simple, yet efficient, real time method of extracting the subject's breathing sinus rhythm. Points of interest are detected on the subject's body, and the corresponding optical flow is estimated and tracked using the well known Lucas-Kanade algorithm on a frame by frame basis. A generalized likelihood ratio test is then utilized on each of the many interest points to detect which is moving in harmonic fashion. Finally, a spectral estimation algorithm based on Pisarenko harmonic decomposition tracks the harmonic frequency in real time, and a fusion maximum likelihood algorithm optimally estimates the breathing rate using all points considered. The results show a maximal error of 1 BPM between the true breathing rate and the algorithm's calculated rate, based on experiments on two babies and three adults.
Full Text Available Satellite Image Time Series (SITS have recently been of great interest due to the emerging remote sensing capabilities for Earth observation. Trend and seasonal components are two crucial elements of SITS. In this paper, a novel framework of SITS decomposition based on Ensemble Empirical Mode Decomposition (EEMD is proposed. EEMD is achieved by sifting an ensemble of adaptive orthogonal components called Intrinsic Mode Functions (IMFs. EEMD is noise-assisted and overcomes the drawback of mode mixing in conventional Empirical Mode Decomposition (EMD. Inspired by these advantages, the aim of this work is to employ EEMD to decompose SITS into IMFs and to choose relevant IMFs for the separation of seasonal and trend components. In a series of simulations, IMFs extracted by EEMD achieved a clear representation with physical meaning. The experimental results of 16-day compositions of Moderate Resolution Imaging Spectroradiometer (MODIS, Normalized Difference Vegetation Index (NDVI, and Global Environment Monitoring Index (GEMI time series with disturbance illustrated the effectiveness and stability of the proposed approach to monitoring tasks, such as applications for the detection of abrupt changes.
Hernandes, Gilberto Luis Sanches [TBG Transportadora Brasileira Gasoduto Bolivia-Brasil, Rio de Janeiro, RJ (Brazil)
This paper presents the results of CBERS-2B' Brazilian Remote Sensing Satellite to help to monitor the Bolivia-Brazil Gas Pipeline. The CBERS-2B is the third satellite launched in 2007 by the CBERS Program (China-Brazil Earth Resources Satellite) and the innovation was the HRC camera that produces high resolution images. It will be possible to obtain one complete coverage of the country every 130 days. In this study, 2 images from different parts of the Bolivia- Brazil Gas Pipeline were selected. Image processing involved the geometric registration of CBERS-2B satellite images with airborne images, contrast stretch transform and pseudo color. The analysis of satellite and airborne images in a GIS software to detect third party encroachment was effective to detect native vegetation removal, street construction, growth of urban areas, farming and residential/industrial land development. Very young, the CBERS-2B is a good promise to help to inspect the areas along the pipelines. (author)
Lamsal, L. N.; Martin, R. V.; Krotkov, N. A.; Bucsela, E. J.; Celarier, E. A.; vanDonkelaar, A.; Parrish, D.
Nitrogen oxides (NO(x)) are key actors in air quality and climate change. Satellite remote sensing of tropospheric NO2 has developed rapidly with enhanced spatial and temporal resolution since initial observations in 1995. We have developed an improved algorithm and retrieved tropospheric NO2 columns from Ozone Monitoring Instrument. Column observations of tropospheric NO2 from the nadir-viewing satellite sensors contain large contributions from the boundary layer due to strong enhancement of NO2 in the boundary layer. We infer ground-level NO2 concentrations from the OMI satellite instrument which demonstrate significant agreement with in-situ surface measurements. We examine how NO2 columns measured by satellite, ground-level NO2 derived from satellite, and NO(x) emissions obtained from bottom-up inventories relate to world's urban population. We perform inverse modeling analysis of NO2 measurements from OMI to estimate "top-down" surface NO(x) emissions, which are used to evaluate and improve "bottom-up" emission inventories. We use NO2 column observations from OMI and the relationship between NO2 columns and NO(x) emissions from a GEOS-Chem model simulation to estimate the annual change in bottom-up NO(x) emissions. The emission updates offer an improved estimate of NO(x) that are critical to our understanding of air quality, acid deposition, and climate change.
Gong, Fang; Wang, Difeng; Huang, Haiqing; Chen, Jianyu
From 2002 to 2004, a satellite data processing system for marine application had been built up in State Key Laboratory of Satellite Ocean Environment Dynamics (Second Institute of Oceanography, State Oceanic Administration). The system received satellite data from TERRA, AQUA, NOAA-12/15/16/17/18, FY-1D and automatically generated Level3 products and Level4 products(products of single orbit and merged multi-orbits products) deriving from Level0 data, which is controlled by an operational control sub-system. Currently, the products created by this system play an important role in the marine environment monitoring, disaster monitoring and researches. Now a distribution platform has been developed on this foundation, namely WebGIS system for querying and browsing of oceanic remote sensing data. This system is based upon large database system-Oracle. We made use of the space database engine of ArcSDE and other middleware to perform database operation in addition. J2EE frame was adopted as development model, and Oracle 9.2 DBMS as database background and server. Simply using standard browsers(such as IE6.0), users can visit and browse the public service information that provided by system, including browsing for oceanic remote sensing data, and enlarge, contract, move, renew, traveling, further data inquiry, attribution search and data download etc. The system is still under test now. Founding of such a system will become an important distribution platform of Chinese satellite oceanic environment products of special topic and category (including Sea surface temperature, Concentration of chlorophyll, and so on), for the exaltation of satellite products' utilization and promoting the data share and the research of the oceanic remote sensing platform.
Leifer, Ira [University of California (United States); Clark, Roger; Swayze, Gregg [US Geology Survey (United States); Jones, Cathleen [California Institute of Technology (United States); Svejkovsky, Jan [Ocean Imaging Corporation (United States)
This study stresses the value of using satellite technology in quantifying oil seepage impact, and how it can be applied to the case of Horizon oil spill. The purpose of the study is to clarify the remote sensing process as it applies to oil spills, and how testing resources should be properly allocated so as to come up with the optimal response strategy. Many parameters were involved in this research, of which the most important were the environmental factors, the active and passive remote sensing measures, satellite imagery and imaging spectroscopy, and oil thickness measurements using thermal infrared and laser-induced fluorescence. These parameters were later used to quantify the spills in the impacted regions. Results showed that remote sensing would always be accompanied by certain errors, however, in the case of the Horizon spill, the infrared approach proved to be a convenient and a reliable approach for impact analysis process. The study also put emphasis on the importance of oil spatial patterns in validating the reliability of a test procedure.
Leifer, Ira; Clark, Roger; Swayze, Gregg; Jones, Cathleen; Svejkovsky, Jan
This study stresses the value of using satellite technology in quantifying oil seepage impact, and how it can be applied to the case of Horizon oil spill. The purpose of the study is to clarify the remote sensing process as it applies to oil spills, and how testing resources should be properly allocated so as to come up with the optimal response strategy. Many parameters were involved in this research, of which the most important were the environmental factors, the active and passive remote sensing measures, satellite imagery and imaging spectroscopy, and oil thickness measurements using thermal infrared and laser-induced fluorescence. These parameters were later used to quantify the spills in the impacted regions. Results showed that remote sensing would always be accompanied by certain errors, however, in the case of the Horizon spill, the infrared approach proved to be a convenient and a reliable approach for impact analysis process. The study also put emphasis on the importance of oil spatial patterns in validating the reliability of a test procedure.
Brown, Molly E.; Pinzon, Jorge E.; Prince, Stephen D.
Famine early warning organizations use data from multiple disciplines to assess food insecurity of communities and regions in less-developed parts of the World. In this paper we integrate several indicators that are available to enhance the information for preparation for and responses to food security emergencies. The assessment uses a price model based on the relationship between the suitability of the growing season and market prices for coarse grain. The model is then used to create spatially continuous maps of millet prices. The model is applied to the dry central and northern areas of West Africa, using satellite-derived vegetation indices for the entire region. By coupling the model with vegetation data estimated for one to four months into the future, maps are created of a leading indicator of potential price movements. It is anticipated that these maps can be used to enable early warning of famine and for planning appropriate responses.
Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati
Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective.
Yamamoto, Y.; Kondoh, T.; Kida, T.; Nishikawa, H.
The thickness of the soil layers in which tree roots are able to develop freely influences forest composition and growth. Trees growing in shallow soil are usually less well supplied with water and mineral nutrients than those growing in deeper soil. A soil may be deep in an absolute sense but, because of a relatively impervious layer, such as hardpan or because of a high water-table, may be shallow in a physiological sense. Penetrability measurements have been found useful in evaluating the influence of different forest types on the physical properties of soils. Commonly the penetrability of soils can be measured by using the Hasegawa-formed soil penetrometer and can be judged as the soil softness content (SSC). Previous studies report soil with more than 1.9 cm/drop of SSC to be highly permeable and therefore roots are more likely to be extensively developed. Based upon this theory the depth of soil layer with more than 1.9 cm/drop of SSC can be defined as the Effective Depth of Soil Layer (EDSL). We examined the relationship between the Ratio Vegetation Index (RVI) and the EDSL and established a 'Runoff Simulation Model (RSM)' based upon the theory of the Storage Function Model method. The conclusions are that (1) a strong positive correlation between the RVI (ground measured) and the EDSL was given, (2) applying results of conclusion (1) to satellite analysis a similar correlation between the RVI (satellite analysis of JERS 1/OPS data) and the EDSL was observed and (3) the simulated storm-runoff hydro graph coincides with the observed one well
Coffield, S. R.; Crosson, W. L.; Al-Hamdan, M. Z.; Barik, M. G.
Consistent and accurate monitoring of the Great Lakes is critical for protecting the freshwater ecosystems, quantifying the impacts of climate change, understanding harmful algal blooms, and safeguarding public health for the millions who rely on the Lakes for drinking water. While ground-based monitoring is often hampered by limited sampling resolution, satellite data provide surface reflectance measurements at much more complete spatial and temporal scales. In this study, we implemented NASA data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite to build robust water quality models. We developed and validated models for chlorophyll-a, nitrogen, phosphorus, and turbidity based on combinations of the six MODIS Ocean Color bands (412, 443, 488, 531, 547, and 667nm) for 2003-2016. Second, we applied these models to quantify trends in water quality through time and in relation to changing land cover, runoff, and climate for six selected coastal areas in Lakes Michigan and Erie. We found strongest models for chlorophyll-a in Lake Huron (R2 = 0.75), nitrogen in Lake Ontario (R2=0.66), phosphorus in Lake Erie (R2=0.60), and turbidity in Lake Erie (R2=0.86). These offer improvements over previous efforts to model chlorophyll-a while adding nitrogen, phosphorus, and turbidity. Mapped water quality parameters showed high spatial variability, with nitrogen concentrated largely in Superior and coastal Michigan and high turbidity, phosphorus, and chlorophyll near urban and agricultural areas of Erie. Temporal analysis also showed concurrence of high runoff or precipitation and nitrogen in Lake Michigan offshore of wetlands, suggesting that water quality in these areas is sensitive to changes in climate.
Satellite system relays communication between aircraft and stations on ground. System offers better coverage with direct communication between air and ground, costs less and makes possible new communication services. Carries both voice and data. Because many data exchanged between aircraft and ground contain safety-related information, probability of bit errors essential.
Wang, Jun; Xu, Xiaoguang; Ding, Shouguo; Zeng, Jing; Spurr, Robert; Liu, Xiong; Chance, Kelly; Mishchenko, Michael
We present a numerical testbed for remote sensing of aerosols, together with a demonstration for evaluating retrieval synergy from a geostationary satellite constellation. The testbed combines inverse (optimal-estimation) software with a forward model containing linearized code for computing particle scattering (for both spherical and non-spherical particles), a kernel-based (land and ocean) surface bi-directional reflectance facility, and a linearized radiative transfer model for polarized radiance. Calculation of gas absorption spectra uses the HITRAN (HIgh-resolution TRANsmission molecular absorption) database of spectroscopic line parameters and other trace species cross-sections. The outputs of the testbed include not only the Stokes 4-vector elements and their sensitivities (Jacobians) with respect to the aerosol single scattering and physical parameters (such as size and shape parameters, refractive index, and plume height), but also DFS (Degree of Freedom for Signal) values for retrieval of these parameters. This testbed can be used as a tool to provide an objective assessment of aerosol information content that can be retrieved for any constellation of (planned or real) satellite sensors and for any combination of algorithm design factors (in terms of wavelengths, viewing angles, radiance and/or polarization to be measured or used). We summarize the components of the testbed, including the derivation and validation of analytical formulae for Jacobian calculations. Benchmark calculations from the forward model are documented. In the context of NASA's Decadal Survey Mission GEO-CAPE (GEOstationary Coastal and Air Pollution Events), we demonstrate the use of the testbed to conduct a feasibility study of using polarization measurements in and around the O 2 A band for the retrieval of aerosol height information from space, as well as an to assess potential improvement in the retrieval of aerosol fine and coarse mode aerosol optical depth (AOD) through the
Wang, N.; Yang, R.
Chinese high -resolution (HR) remote sensing satellites have made huge leap in the past decade. Commercial satellite datasets, such as GF-1, GF-2 and ZY-3 images, the panchromatic images (PAN) resolution of them are 2 m, 1 m and 2.1 m and the multispectral images (MS) resolution are 8 m, 4 m, 5.8 m respectively have been emerged in recent years. Chinese HR satellite imagery has been free downloaded for public welfare purposes using. Local government began to employ more professional technician to improve traditional land management technology. This paper focused on analysing the actual requirements of the applications in government land law enforcement in Guangxi Autonomous Region. 66 counties in Guangxi Autonomous Region were selected for illegal land utilization spot extraction with fusion Chinese HR images. The procedure contains: A. Defines illegal land utilization spot type. B. Data collection, GF-1, GF-2, and ZY-3 datasets were acquired in the first half year of 2016 and other auxiliary data were collected in 2015. C. Batch process, HR images were collected for batch preprocessing through ENVI/IDL tool. D. Illegal land utilization spot extraction by visual interpretation. E. Obtaining attribute data with ArcGIS Geoprocessor (GP) model. F. Thematic mapping and surveying. Through analysing 42 counties results, law enforcement officials found 1092 illegal land using spots and 16 suspicious illegal mining spots. The results show that Chinese HR satellite images have great potential for feature information extraction and the processing procedure appears robust.
Nakajima, Teruyuki; Hashimoto, Makiko; Takenaka, Hideaki; Goto, Daisuke; Oikawa, Eiji; Suzuki, Kentaroh; Uchida, Junya; Dai, Tie; Shi, Chong
The rapid growth of satellite remote sensing technologies in the last two decades widened the utility of satellite data for understanding climate impacts of aerosols and clouds. The climate modeling community also has received the benefit of the earth observation and nowadays closed-collaboration of the two communities make us possible to challenge various applications for societal problems, such as for global warming and global-scale air pollution and others. I like to give several thoughts of new algorithm developments, model use of satellite data for climate impact studies and societal applications related with aerosols and clouds. Important issues are 1) Better aerosol detection and solar energy application using expanded observation ability of the third generation geostationary satellites, i.e. Himawari-8, GOES-R and future MTG, 2) Various observation functions by directional, polarimetric, and high resolution near-UV band by MISR, POLDER&PARASOL, GOSAT/CAI and future GOSAT2/CAI2, 3) Various applications of general purpose-imagers, MODIS, VIIRS and future GCOM-C/SGLI, and 4) Climate studies of aerosol and cloud stratification and convection with active and passive sensors, especially climate impact of BC aerosols using CLOUDSAT&CALIPSO and future Earth Explorer/EarthCARE.
Y. H. Ahn
.98 rather than a linear function of salinity measured in a variety of water types from this and other regions. Validation against a discrete in-situ data set showed that empirical algorithms derived from the above relationships could be successfully applied to satellite data over the range of water types for which they have been developed. Thus, we applied these algorithms to a series of SeaWiFS images for the derivation of CDOM and salinity in the context of operational mapping and monitoring of the springtime evolution of LSW plume in the ECS. The results were very encouraging and showed interesting features in surface CDOM and salinity fields in the vicinity of the Yangtze River estuary and its offshore domains, when a regional atmospheric correction (SSMM was employed instead of the standard (global SeaWiFS algorithm (SAC which revealed large errors around the edges of clouds/aerosols while masking out the nearshore areas. Nevertheless, there was good consistency between these two atmospheric correction algorithms over the relatively clear regions with a mean difference of 0.009 in aCDOM (400 (m−1 and 0.096 in salinity (psu. This study suggests the possible utilization of satellite remote sensing to assess CDOM and salinity and thus provides great potential in advancing our knowledge of the shelf-slope evolution and migration of the LSW plume properties in the ECS.
The angular distribution of radiation scattered by the earth surface contains information on the structural and optical properties of the surface. Potentially, this information may be retrieved through the inversion of surface bidirectional reflectance distribution function (BRDF) models. This report details the limitations and efficient application of BRDF model inversions using data from ground- and satellite-based sensors. A turbid medium BRDF model, based on the discrete ordinates solution to the transport equation, was used to quantify the sensitivity of top-of-canopy reflectance to vegetation and soil parameters. Results were used to define parameter sets for inversions. Using synthetic reflectance values, the invertibility of the model was investigated for different optimization algorithms, surface and sampling conditions. Inversions were also conducted with field data from a ground-based radiometer. First, a soil BRDF model was inverted for different soil and sampling conditions. A condition-invariant solution was determined and used as the lower boundary condition in canopy model inversions. Finally, a scheme was developed to improve the speed and accuracy of inversions.
Ramos Turci, Luiz Felipe; Macau, Elbert E.N.; Yoneyama, Takashi
In this work, we investigate the use of the Dynamical System Theory to increase the efficiency of the satellite power supply subsystems. The core of a satellite power subsystem relies on its DC/DC converter. This is a very nonlinear system that presents a multitude of phenomena ranging from bifurcations, quasi-periodicity, chaos, coexistence of attractors, among others. The traditional power subsystem design techniques try to avoid these nonlinear phenomena so that it is possible to use linear system theory in small regions about the equilibrium points. Here, we show that more efficiency can be drawn from a power supply subsystem if the DC/DC converter operates in regions of high nonlinearity. In special, if it operates in a chaotic regime, is has an intrinsic sensitivity that can be exploited to efficiently drive the power subsystem over high ranges of power requests by using control of chaos techniques.
Ramos Turci, Luiz Felipe [Technological Institute of Aeronautics (ITA), Sao Jose dos Campos, SP (Brazil)], E-mail: email@example.com; Macau, Elbert E.N. [National Institute of Space Research (Inpe), Sao Jose dos Campos, SP (Brazil)], E-mail: firstname.lastname@example.org; Yoneyama, Takashi [Technological Institute of Aeronautics (ITA), Sao Jose dos Campos, SP (Brazil)], E-mail: email@example.com
In this work, we investigate the use of the Dynamical System Theory to increase the efficiency of the satellite power supply subsystems. The core of a satellite power subsystem relies on its DC/DC converter. This is a very nonlinear system that presents a multitude of phenomena ranging from bifurcations, quasi-periodicity, chaos, coexistence of attractors, among others. The traditional power subsystem design techniques try to avoid these nonlinear phenomena so that it is possible to use linear system theory in small regions about the equilibrium points. Here, we show that more efficiency can be drawn from a power supply subsystem if the DC/DC converter operates in regions of high nonlinearity. In special, if it operates in a chaotic regime, is has an intrinsic sensitivity that can be exploited to efficiently drive the power subsystem over high ranges of power requests by using control of chaos techniques.
Zhang, G.; Perrie, W. A.; Liu, G.; Zhang, L.
Hurricanes over the ocean have been observed by spaceborne aperture radar (SAR) since the first SAR images were available in 1978. SAR has high spatial resolution (about 1 km), relatively large coverage and capability for observations during almost all-weather, day-and-night conditions. In this study, seven C-band RADARSAT-2 dual-polarized (VV and VH) ScanSAR wide images from the Canadian Space Agency (CSA) Hurricane Watch Program in 2017 are collected over five hurricanes: Harvey, Irma, Maria, Nate, and Ophelia. We retrieve the ocean winds by applying our C-band Cross-Polarization Coupled-Parameters Ocean (C-3PO) wind retrieval model [Zhang et al., 2017, IEEE TGRS] to the SAR images. Ocean waves are estimated by applying a relationship based on the fetch- and duration-limited nature of wave growth inside hurricanes [Hwang et al., 2016; 2017, J. Phys. Ocean.]. We estimate the ocean surface currents using the Doppler Shift extracted from VV-polarized SAR images [Kang et al., 2016, IEEE TGRS]. C-3PO model is based on theoretical analysis of ocean surface waves and SAR microwave backscatter. Based on the retrieved ocean winds, we estimate the hurricane center locations, maxima wind speeds, and radii of the five hurricanes by adopting the SHEW model (Symmetric Hurricane Estimates for Wind) by Zhang et al. [2017, IEEE TGRS]. Thus, we investigate possible relations between hurricane structures and intensities, and especially some possible effects of the asymmetrical characteristics on changes in the hurricane intensities, such as the eyewall replacement cycle. The three SAR images of Ophelia include the north coast of Ireland and east coast of Scotland allowing study of ocean surface currents respond to the hurricane. A system of methods capable of observing marine winds, surface waves, and surface currents from satellites is of value, even if these data are only available in near real-time or from SAR-related satellite images. Insight into high resolution ocean winds
Sagawa, Tatsuyuki; Komatsu, Teruhisa
Seagrass and seaweed beds play important roles in coastal marine ecosystems. They are food sources and habitats for many marine organisms, and influence the physical, chemical, and biological environment. They are sensitive to human impacts such as reclamation and pollution. Therefore, their management and preservation are necessary for a healthy coastal environment. Satellite remote sensing is a useful tool for mapping and monitoring seagrass beds. The efficiency of seagrass mapping, seagrass bed classification in particular, has been evaluated by mapping accuracy using an error matrix. However, mapping accuracies are influenced by coastal environments such as seawater transparency, bathymetry, and substrate type. Coastal management requires sufficient accuracy and an understanding of mapping limitations for monitoring coastal habitats including seagrass beds. Previous studies are mainly based on case studies in specific regions and seasons. Extensive data are required to generalise assessments of classification accuracy from case studies, which has proven difficult. This study aims to build a simulator based on a radiative transfer model to produce modelled satellite images and assess the visual detectability of seagrass beds under different transparencies and seagrass coverages, as well as to examine mapping limitations and classification accuracy. Our simulations led to the development of a model of water transparency and the mapping of depth limits and indicated the possibility for seagrass density mapping under certain ideal conditions. The results show that modelling satellite images is useful in evaluating the accuracy of classification and that establishing seagrass bed monitoring by remote sensing is a reliable tool.
Akhand, Kawsar; Nizamuddin, Mohammad; Roytman, Leonid; Kogan, Felix
Potato is one of the staple foods and cash crops in Bangladesh. It is widely cultivated in all of the districts and ranks second after rice in production. Bangladesh is the fourth largest potato producer in Asia and is among the world's top 15 potato producing countries. The weather condition for potato cultivation is favorable during the sowing, growing and harvesting period. It is a winter crop and is cultivated during the period of November to March. Bangladesh is mainly an agricultural based country with respect to agriculture's contribution to GDP, employment and consumption. Potato is a prominent crop in consideration of production, its internal demand and economic value. Bangladesh has a big economic activities related to potato cultivation and marketing, especially the economic relations among farmers, traders, stockers and cold storage owners. Potato yield prediction before harvest is an important issue for the Government and the stakeholders in managing and controlling the potato market. Advanced very high resolution radiometer (AVHRR) based satellite data product vegetation health indices VCI (vegetation condition index) and TCI (temperature condition index) are used as predictors for early prediction. Artificial neural network (ANN) is used to develop a prediction model. The simulated result from this model is encouraging and the error of prediction is less than 10%.
Full Text Available Remote laboratories play an important role in the educational process of engineers. This paper deals with the structure of remote laboratories. The principle of the proposed remote laboratory structure is based on the Java server application that communicates with Matlab through the COM technology for the data exchange under the Windows operating system. Java does not support COM directly so the results of the JACOB project are used and modified to cope with this problem. In laboratories for control engineering education a control algorithm usually runs on a PC with Matlab that really controls the real plant. This is the server side described in the paper in details. To demonstrate the possibilities of a remote control a Java client server application is also introduced. It covers communication and offers a user friendly interface for the control of a remote plant and visualization of measured data.
Full Text Available The Tibetan Plateau (TP has been observed by satellite optical remote sensing, altimetry, and gravimetry for a variety of geophysical parameters, including water storage change. However, each of these sensors has its respective limitation in the parameters observed, accuracy and spatial-temporal resolution. Here, we utilized an integrated approach to combine remote sensing imagery, digital elevation model, and satellite radar and laser altimetry data, to quantify freshwater storage change in a twin lake system named Chibuzhang Co and Dorsoidong Co in the central TP, and compared that with independent observations including mass changes from the Gravity Recovery and Climate Experiment (GRACE data. Our results show that this twin lake, located within the Tanggula glacier system, remained almost steady during 1973–2000. However, Dorsoidong Co has experienced a significant lake level rise since 2000, especially during 2000–2005, that resulted in the plausible connection between the two lakes. The contemporary increasing lake level signal at a rate of 0.89 ± 0.05 cm·yr−1, in a 2° by 2° grid equivalent water height since 2002, is higher than the GRACE observed trend at 0.41 ± 0.17 cm·yr−1 during the same time span. Finally, a down-turning trend or inter-annual variability shown in the GRACE signal is observed after 2012, while the lake level is still rising at a consistent rate.
specific point in time; Timewave: Amount of motion and symmetry of wave shape (i.e., a truncated wave can be an indication of a rub); Orbits: A cross-sectional view of shaft movement; DC Gap Voltage: A measurement of the distance (e.g., gap) between the shaft and the proximity probes. This value is useful in determining bearing wear of shaft centerline location. Daily monitoring of these metrics will not only warn of impending failure, but provide valuable information regarding the possible cause of the impending failure and an approximate indication of time to failure. In the event of a sudden problem and subsequent trip of a turbine, this data helps determine the root cause of the failure. This results in faster problem resolution and a quicker restart of the turbine. Additionally, daily monitoring of these metrics allows companies to watch a problematic turbine's health until the next scheduled outage. Azima's remote, condition-based monitoring system and diagnostics service is an effective way to collect and trend these metrics on a daily basis, as well as supply expert advice in the event of any anomalies. The Azima system aggregates the analog data from the proximity probes mounted on the turbine at a sensor hub. The sensor hub digitizes the analog data and then, either wirelessly or through a wired Ethernet connection, sends the data via the Internet to a hosted server. The hosted server maintains the software that trends the data (e.g., vibration, spectrum, timewave, DC gap voltage, and orbits) and provides automatic alerting. The data can be accessed anywhere, anytime through a standard Web browser. The advantages of daily, remote, condition-based monitoring include: Daily monitoring of vital turbine health metrics to detect impending problems before they become critical; Automatic alerting when a change in condition is detected; Anywhere, anytime access via a standard Web browser. This allows multiple groups at different locations to simultaneously review and
Badger, Merete; Astrup, Poul; Hasager, Charlotte Bay
variations are clearly visible across the domain; for instance sheltering effects caused by the land masses. The satellite based wind resource maps have two shortcomings. One is the lack of information at the higher vertical levels where wind turbines operate. The other is the limited number of overlapping...... years of WRF data – specifically the parameters heat flux, air temperature, and friction velocity – are used to calculate a long-term correction for atmospheric stability effects. The stability correction is applied to the satellite based wind resource maps together with a vertical wind profile...... from satellite synthetic aperture radar (SAR) data are particularly suitable for offshore wind energy applications because they offer a spatial resolution up to 500 m and include coastal seas. In this presentation, satellite wind maps are used in combination with mast observations and numerical...
Broich, M.; Tulbure, M. G.; Wijaya, A.; Weisse, M.; Stolle, F.
Deforestation and forest degradation form the 2nd largest source of anthropogenic CO2 emissions. While deforestation is being globally mapped with satellite image time series, degradation remains insufficiently quantified. Previous studies quantified degradation for small scale, local sites. A method suitable for accurate mapping across large areas has not yet been developed due to the variability of the low magnitude and short-lived degradation signal and the absence of data with suitable resolution properties. Here we use a combination of newly available streams of free optical and radar image time series acquired by NASA and ESA, and HPC-based data science algorithms to innovatively quantify degradation consistently across Southeast Asia (SEA). We used Sentinel1 c-band radar data and NASA's new Harmonized Landsat8 (L8) Sentinel2 (S2) product (HLS) for cloud free optical images. Our results show that dense time series of cloud penetrating Sentinel 1 c-band radar can provide degradation alarm flags, while the HLS product of cloud-free optical images can unambiguously confirm degradation alarms. The detectability of degradation differed across SEA. In the seasonal forest of continental SEA the reliability of our radar-based alarm flags increased as the variability in landscape moisture decreases in the dry season. We reliably confirmed alarms with optical image time series during the late dry season, where degradation in open canopy forests becomes detectable once the undergrowth vegetation has died down. Conversely, in insular SEA landscape moisture is low, the radar time series generated degradation alarms flags with moderate to high reliability throughout the year, further confirmed with the HLS product. Based on the HLS product we can now confirm degradation within time series provides better results than either one on its own. Our results provide significant information with application for carbon trading policy and land management.
Harsa, Hastuadi; Buono, Agus; Hidayat, Rahmat; Achyar, Jaumil; Noviati, Sri; Kurniawan, Roni; Praja, Alfan S.
Rainfall datasets are available from various sources, including satellite estimates and ground observation. The locations of ground observation scatter sparsely. Therefore, the use of satellite estimates is advantageous, because satellite estimates can provide data on places where the ground observations do not present. However, in general, the satellite estimates data contain bias, since they are product of algorithms that transform the sensors response into rainfall values. Another cause may come from the number of ground observations used by the algorithms as the reference in determining the rainfall values. This paper describe the application of bias correction method to modify the satellite-based dataset by adding a number of ground observation locations that have not been used before by the algorithm. The bias correction was performed by utilizing Quantile Mapping procedure between ground observation data and satellite estimates data. Since Quantile Mapping required mean and standard deviation of both the reference and the being-corrected data, thus the Inverse Distance Weighting scheme was applied beforehand to the mean and standard deviation of the observation data in order to provide a spatial composition of them, which were originally scattered. Therefore, it was possible to provide a reference data point at the same location with that of the satellite estimates. The results show that the new dataset have statistically better representation of the rainfall values recorded by the ground observation than the previous dataset.
Ichii, K.; Kondo, M.; Wang, W.; Hashimoto, H.; Nemani, R. R.
Various satellite-based spatial products such as evapotranspiration (ET) and gross primary productivity (GPP) are now produced by integration of ground and satellite observations. Effective use of these multiple satellite-based products in terrestrial biosphere models is an important step toward better understanding of terrestrial carbon and water cycles. However, due to the complexity of terrestrial biosphere models with large number of model parameters, the application of these spatial data sets in terrestrial biosphere models is difficult. In this study, we established an effective but simple framework to refine a terrestrial biosphere model, Biome-BGC, using multiple satellite-based products as constraints. We tested the framework in the monsoon Asia region covered by AsiaFlux observations. The framework is based on the hierarchical analysis (Wang et al. 2009) with model parameter optimization constrained by satellite-based spatial data. The Biome-BGC model is separated into several tiers to minimize the freedom of model parameter selections and maximize the independency from the whole model. For example, the snow sub-model is first optimized using MODIS snow cover product, followed by soil water sub-model optimized by satellite-based ET (estimated by an empirical upscaling method; Support Vector Regression (SVR) method; Yang et al. 2007), photosynthesis model optimized by satellite-based GPP (based on SVR method), and respiration and residual carbon cycle models optimized by biomass data. As a result of initial assessment, we found that most of default sub-models (e.g. snow, water cycle and carbon cycle) showed large deviations from remote sensing observations. However, these biases were removed by applying the proposed framework. For example, gross primary productivities were initially underestimated in boreal and temperate forest and overestimated in tropical forests. However, the parameter optimization scheme successfully reduced these biases. Our analysis
Raj Kumar Tiwari; Santosh Kumar Agrahari
The embedded systems are widely used for the data acquisition. The data acquired may be used for monitoring various activity of the system or it can be used to control the parts of the system. Accessing various signals with remote location has greater advantage for multisite operation or unmanned systems. The remote data acquisition used in this paper is based on ARM processor. The Cortex M3 processor used in this system has in-built Ethernet controller which facilitate to acquire the remote ...
Aanæs, Henrik; Sveinsson, J. R.; Nielsen, Allan Aasbjerg
A method is proposed for pixel-level satellite image fusion derived directly from a model of the imaging sensor. By design, the proposed method is spectrally consistent. It is argued that the proposed method needs regularization, as is the case for any method for this problem. A framework for pixel...... neighborhood regularization is presented. This framework enables the formulation of the regularization in a way that corresponds well with our prior assumptions of the image data. The proposed method is validated and compared with other approaches on several data sets. Lastly, the intensity......-hue-saturation method is revisited in order to gain additional insight of what implications the spectral consistency has for an image fusion method....
Lin, J.; McElroy, M. B.; Boersma, F.; Nielsen, C.; Zhao, Y.; Lei, Y.; Liu, Y.; Zhang, Q.; Liu, Z.; Liu, H.; Mao, J.; Zhuang, G.; Roozendael, M.; Martin, R.; Wang, P.; Spurr, R. J.; Sneep, M.; Stammes, P.; Clemer, K.; Irie, H.
Vertical column densities (VCDs) of tropospheric nitrogen dioxide (NO2) retrieved from satellite remote sensing have been employed widely to constrain emissions of nitrogen oxides (NOx). A major strength of satellite-based emission constraint is analysis of emission trends and variability, while a crucial limitation is errors both in satellite NO2 data and in model simulations relating NOx emissions to NO2 columns. Through a series of studies, we have explored these aspects over China. We separate anthropogenic from natural sources of NOx by exploiting their different seasonality. We infer trends of NOx emissions in recent years and effects of a variety of socioeconomic events at different spatiotemporal scales including the general economic growth, global financial crisis, Chinese New Year, and Beijing Olympics. We further investigate the impact of growing NOx emissions on particulate matter (PM) pollution in China. As part of recent developments, we identify and correct errors in both satellite NO2 retrieval and model simulation that ultimately affect NOx emission constraint. We improve the treatments of aerosol optical effects, clouds and surface reflectance in the NO2 retrieval process, using as reference ground-based MAX-DOAS measurements to evaluate the improved retrieval results. We analyze the sensitivity of simulated NO2 to errors in the model representation of major meteorological and chemical processes with a subsequent correction of model bias. Future studies will implement these improvements to re-constrain NOx emissions.
Full Text Available Passive radar is a topic anti stealth technology with simple structure, and low cost. Radiation source model, signal transmission model, and target detection are the key points of passive radar technology research. The paper analyzes the characteristics of EBPSK signal modulation and target detection method aspect of spaceborne radiant source. By comparison with other satellite navigation and positioning system, the characteristics of EBPSK satellite passive radar system are analyzed. It is proved that the maximum detection range of EBPSK satellite signal can satisfy the needs of the proposed model. In the passive radar model, sparse representation is used to achieve high resolution DOA detection. The comparison with the real target track by simulation demonstrates that effective detection of airborne target using EBPSK satellite passive radar system based on sparse representation is efficient.
Yunck, T. P.; Melbourne, W. G.; Thornton, C. L.
NASA is developing a Global Positioning System (GPS) based measurement system to provide precise determination of earth satellite orbits, geodetic baselines, ionospheric electron content, and clock offsets between worldwide tracking sites. The system will employ variations on the differential GPS observing technique and will use a network of nine fixed ground terminals. Satellite applications will require either a GPS flight receiver or an on-board GPS beacon. Operation of the system for all but satellite tracking will begin by 1988. The first major satellite application will be a demonstration of decimeter accuracy in determining the altitude of TOPEX in the early 1990's. By then the system is expected to yield long-baseline accuracies of a few centimeters and instantaneous time synchronization to 1 ns.
Full Text Available New High Throughput Satellite (HTS systems allow high throughput IP uplinks/contribution at Ka-band frequencies for relatively lower costs when compared to broadcasting satellite uplinks at Ku band. This technology offers an advantage for live video contribution from remote areas, where the terrestrial infrastructure may not be adequate. On the other hand, the Ka-band is more subject to impairments due to rain or bad weather. This paper addresses the target system specification and provides an optimized approach for the transmission of IP-based video flows through HTS commercial services operating at Ka-band frequencies. In particular, the focus of this study is on the service requirements and the propagation analysis that provide a reference architecture to improve the overall link availability. The approach proposed herein leads to the introduction of a new concept of live service contribution using pairs of small satellite antennas and cheap satellite terminals.
We often need for software registration to protect the interests of the software developers. This article narrated one kind of software long-distance registration technology. The registration method is: place the registration information in a database table, after the procedure starts in check table registration information, if it has registered then the procedure may the normal operation; Otherwise, the customer must input the sequence number and registers through the network on the long-distance server. If it registers successfully, then records the registration information in the database table. This remote registration method can protect the rights of software developers.
Hou, Ying-Yu; He, Yan-Bo; Wang, Jian-Lin; Tian, Guo-Liang
Based on the time series 10-day composite NOAA Pathfinder AVHRR Land (PAL) dataset (8 km x 8 km), and by using land surface energy balance equation and "VI-Ts" (vegetation index-land surface temperature) method, a new algorithm of land surface evapotranspiration (ET) was constructed. This new algorithm did not need the support from meteorological observation data, and all of its parameters and variables were directly inversed or derived from remote sensing data. A widely accepted ET model of remote sensing, i. e., SEBS model, was chosen to validate the new algorithm. The validation test showed that both the ET and its seasonal variation trend estimated by SEBS model and our new algorithm accorded well, suggesting that the ET estimated from the new algorithm was reliable, being able to reflect the actual land surface ET. The new ET algorithm of remote sensing was practical and operational, which offered a new approach to study the spatiotemporal variation of ET in continental scale and global scale based on the long-term time series satellite remote sensing images.
Noakes, M.W.; Richardson, B.S.; Rowe, J.C.; Draper, J.V.; Sandness, G.R.
The detection and characterization of buried objects and materials is an important first step in the restoration of the numerous US Department of Energy (DOE) and US Department of Defense waste disposal sites. DOE, through its Environmental Restoration and Waste Management Robotics and Technology Development Program, has developed the Remote Characterization System (RCS) to address the needs of remote subsurfacecharacterization. The RCS consists of a low-metal-content (low-metallic-signature) remotely piloted vehicle, a high-level control station (HLCS) where operators can remotely control the vehicle and analyze real-time data from sensors, and an array of sensors that can be chosen to meet the survey task at hand. Communication between the vehicle and the base station is handled by a radio link. Site mapping is made possible through the use of geopositioning satellite data. The primary mode of vehicle operation is teleoperation, but provision has been made for semiautonomous or supervisory control that allows for automated sitesurvey on simple sites. Data analysis and display is supported for both real-time observation and postprocessing of data. The particular emphasis of this paper documents the human-factors-based design influences on the HLCS and describes the design in detail
Goetz, Alexander F. H.
The application of remote sensing techniques to mineral exploration involves the use of both spatial (morphological) as well as spectral information. This paper is directed toward a discussion of the uses of spectral image information and emphasizes the newest airborne and spaceborne sensor developments involving imaging spectrometers.
McCarthy, Matthew J; Colna, Kaitlyn E; El-Mezayen, Mahmoud M; Laureano-Rosario, Abdiel E; Méndez-Lázaro, Pablo; Otis, Daniel B; Toro-Farmer, Gerardo; Vega-Rodriguez, Maria; Muller-Karger, Frank E
Management of coastal and marine natural resources presents a number of challenges as a growing global population and a changing climate require us to find better strategies to conserve the resources on which our health, economy, and overall well-being depend. To evaluate the status and trends in changing coastal resources over larger areas, managers in government agencies and private stakeholders around the world have increasingly turned to remote sensing technologies. A surge in collaborative and innovative efforts between resource managers, academic researchers, and industry partners is becoming increasingly vital to keep pace with evolving changes of our natural resources. Synoptic capabilities of remote sensing techniques allow assessments that are impossible to do with traditional methods. Sixty years of remote sensing research have paved the way for resource management applications, but uncertainties regarding the use of this technology have hampered its use in management fields. Here we review examples of remote sensing applications in the sectors of coral reefs, wetlands, water quality, public health, and fisheries and aquaculture that have successfully contributed to management and decision-making goals.
McCarthy, Matthew J.; Colna, Kaitlyn E.; El-Mezayen, Mahmoud M.; Laureano-Rosario, Abdiel E.; Méndez-Lázaro, Pablo; Otis, Daniel B.; Toro-Farmer, Gerardo; Vega-Rodriguez, Maria; Muller-Karger, Frank E.
Management of coastal and marine natural resources presents a number of challenges as a growing global population and a changing climate require us to find better strategies to conserve the resources on which our health, economy, and overall well-being depend. To evaluate the status and trends in changing coastal resources over larger areas, managers in government agencies and private stakeholders around the world have increasingly turned to remote sensing technologies. A surge in collaborative and innovative efforts between resource managers, academic researchers, and industry partners is becoming increasingly vital to keep pace with evolving changes of our natural resources. Synoptic capabilities of remote sensing techniques allow assessments that are impossible to do with traditional methods. Sixty years of remote sensing research have paved the way for resource management applications, but uncertainties regarding the use of this technology have hampered its use in management fields. Here we review examples of remote sensing applications in the sectors of coral reefs, wetlands, water quality, public health, and fisheries and aquaculture that have successfully contributed to management and decision-making goals.
Menenti, M.; Mulders, C.W.B.
This report describes the development and adaptation of distributed numerical simulation models of hydrological processes in complex watersheds typical of the Andean region. These distributed models take advantage of the synoptic capabilities of sensors on-board satellites and GIS procedures have
The glaciers in western Karakoram are important for freshwater supply in the rivers of Pakistan. Global warming influences the future water supply from glaciers. In order to study the hydrological conditions and possible impacts of climate change, runoff simulations are performed for the Hunza basin. The hydrological modelling system SRM (Snowmelt Runoff Model) is customized and applied to the Hunza basin. Various data obtained from satellite remote sensing imagery and meteorological stations in the study area are processed, prepared and used as input to SRM. For runoff simulations the basin is divided into five sub-basins. The (sub-) basins are defined by the hydrological response units (HRU) based on the elevation zones and land-cover types. The spatially distributed data are aggregated HRU-wise as input for the model simulations. The energy available for snow and glacier melt is parameterized in SRM by degree day factors which are defined separately for seasonal snow, ice and debris covered glaciers. The model is calibrated for the Hunza basin using the meteorological and remote sensing data from years 2002 and 2003. The daily runoff is simulated and compared with the measured discharge data obtained from the power company. The Nash-Sutcliffe correlation coefficient of simulated versus measured runoff data is 0.87 for year 2002 and 0.96 for year 2003 which indicates a good agreement. An estimation of mass balance of Baltoro glacier is made using the meteorological data from Shigar station applying the hydrological method to estimate accumulation and melt. Based on these data is found that Baltoro glacier has slightly negative mass balance. The ablation rates of debris covered parts of Baltoro glacier at 4150 m elevation are estimated to be between 3 and 4 cm per day. However, the uncertainty in mass balance modelling is high due to poor knowledge of accumulation inferred by spatial extrapolation from station data.Keeping the glacier area unchanged, for the 2002
Full Text Available The present study focuses on the unprecedented flood situation captured through multi-temporal satellite images, witnessed along the Ganga River in Uttar Pradesh during September 2010. At three gauge stations (Kannauj, Ankinghat and Kanpur, river water level exceeded the previous high-flood level attained by river more than a decade ago. The present communication with the aid of pre- and post-flood satellite images, coupled with hydrological (river water level and meteorological (rainfall data, explains about the unprecedented flood situation. In the latter part of the study, a novel and cost-effective method for building a library of flood inundation extents based on historical satellite data analysis and tagging the inundation layer with observed water level is demonstrated. During flood season, based on the forecasted water level, the library can be accessed to fetch the spatial inundation layer corresponding to the forecasted stage and anticipate in advance, likely spatial inundation pattern and submergence of villages and hence in alerting the habitation at risk. This method can be helpful in anticipating the areas to be affected in situations where satellite images cannot be effectively utilized due to cloud cover and also for providing information about the areas being partially covered in satellite data.
Aug 31, 2017 ... Due to inadequate radar network, satellite plays the dominant role for nowcast of these thunderstorms. In this study, a nowcast based algorithm ForTracc developed by Vila ... of actual development of cumulonimbus clouds, ... MCS over Indian region using Infrared Channel ... (2016) based on case study of.
Clodius, W.B.; Weber, P.G.; Borel, C.C.; Smith, B.W.
The design of satellite based multispectral imaging systems requires the consideration of a number of tradeoffs between cost and performance. The authors have recently been involved in the design and evaluation of a satellite based multispectral sensor operating from the visible through the long wavelength IR. The criteria that led to some of the proposed designs and the modeling used to evaluate and fine tune the designs will both be discussed. These criteria emphasized the use of bands for surface temperature retrieval and the correction of atmospheric effects. The impact of cost estimate changes on the final design will also be discussed
Brown, Molly E.; Grace, Kathryn; Shively, Gerald; Johnson, Kiersten B.; Carroll, Mark
Climate change and degradation of ecosystem services functioning may threaten the ability of current agricultural systems to keep up with demand for adequate and inexpensive food and for clean water, waste disposal and other broader ecosystem services. Human health is likely to be affected by changes occurring across multiple geographic and time scales. Impacts range from increasing transmissibility and the range of vector-borne diseases, such as malaria and yellow fever, to undermining nutrition through deleterious impacts on food production and concomitant increases in food prices. This paper uses case studies to describe methods that make use of satellite remote sensing and Demographic and Health Survey data to better understand individual-level human health and nutrition outcomes. By bringing these diverse datasets together, the connection between environmental change and human health outcomes can be described through new research and analysis.
Kindt-Larsen, Lotte; Berg, Casper Willestofte; Tougaard, J.
grounds, quantify fishing effort and document harbour porpoise bycatch. Movement data from 66 harbour porpoises equipped with satellite transmitters from 1997 to 2012 were used to model population density. A simple model was constructed to investigate the relationship between the response (number...... telemetry or REM data allow for identification of areas of potential high and low bycatch risk, and better predictions are obtained when combining the 2 sources of data. The final model can thus be used as a tool to identify areas of bycatch risk...... and lower risk of porpoise bycatch. From May 2010 to April 2011, 4 commercial gillnet vessels were equipped with remote electronic monitoring (REM) systems. The REM system recorded time, GPS position and closed-circuit television (CCTV) footage of all gillnet hauls. REM data were used to identify fishing...
Full Text Available The upper ranges of the northern Andes are characterized by unique Neotropical, high altitude ecosystems known as paramos. These tundra-like grasslands are widely recognized by the scientific community for their biodiversity and their important ecosystem services for the local human population. Despite their remoteness, limited accessibility for humans and waterlogged soils, paramos are highly flammable ecosystems. They are constantly under the influence of seasonal biomass burning mostly caused by humans. Nevertheless, little is known about the spatial extent of these fires, their regime and the resulting ecological impacts. This paper presents a thorough mapping and analysis of the fires in one of the world’s largest paramo, namely the “Complejo de Páramos” of Cruz Verde-Sumapaz in the Eastern mountain range of the Andes (Colombia. Landsat TM/ETM+ and MODIS imagery from 2001 to 2013 was used to map and analyze the spatial distribution of fires and their intra- and inter-annual variability. Moreover, a logistic regression model analysis was undertaken to test the hypothesis that the dynamics of the paramo fires can be related to human pressures. The resulting map shows that the burned paramo areas account for 57,179.8 hectares, of which 50% (28,604.3 hectares are located within the Sumapaz National Park. The findings show that the fire season mainly occurs from January to March. The accuracy assessment carried out using a confusion matrix based on 20 reference burned areas shows values of 90.1% (producer accuracy for the mapped burned areas with a Kappa Index of Agreement (KIA of 0.746. The results of the logistic regression model suggest a significant predictive relevance of the variables road distance (0.55 ROC (receiver operating characteristic and slope gradient (0.53 ROC, indicating that the higher the probability of fire occurrence, the smaller the distance to the road and the higher the probability of more gentle slopes. The paper
Mitchell, D. L.; Garnier, A.; Mejia, J.; Avery, M. A.; Erfani, E.
To date, it is not clear whether the climate intervention method known as cirrus cloud thinning (CCT) can be viable since it requires cirrus clouds to form through homogeneous ice nucleation (henceforth hom) and some recent GCM studies predict cirrus are formed primarily through heterogeneous ice nucleation (henceforth het). A new CALIPSO infrared retrieval method has been developed for single-layer cirrus cloud that measures the temperature dependence of their layer-averaged number concentration N, effective diameter De and ice water content for optical depths (OD) between 0.3 and 3.0. Based on N, the prevailing ice nucleation mechanism (hom or het) can be estimated as a function of temperature, season, latitude and surface type. These satellite results indicate that seeding cirrus clouds at high latitudes during winter may produce significant global surface cooling. This is because hom often appears to dominate over land during winter north of 30°N latitude while the same appears true for most of the Southern Hemisphere (south of 30°S) during all seasons. Moreover, the sampled cirrus cloud frequency of occurrence in the Arctic is at least twice as large during winter relative to other seasons, while frequency of occurrence in the Antarctic peaks in the spring and is second-highest during winter. During Arctic winter, a combination of frequent hom cirrus, maximum cirrus coverage and an extreme or absent sun angle produces the maximum seasonal cirrus net radiative forcing (warming). Thus a reduction in OD and coverage (via CCT) for these cirrus clouds could yield a significant net cooling effect. From these CALIPSO retrievals, De-T relationships are generated as a function of season, latitude and surface type (land vs. ocean). These will be used in CAM5 to estimate De and the ice fall speed, from which the cirrus radiative forcing will be estimated during winter north of 30°latitude, where hom cirrus are common. Another CAM5 simulation will replace the hom
Full Text Available Natural crude-oil seepages, together with the oil released into seawater as a consequence of oil exploration/production/transportation activities, and operational discharges from tankers (i.e., oil dumped during cleaning actions represent the main sources of sea oil pollution. Satellite remote sensing can be a useful tool for the management of such types of marine hazards, namely oil spills, mainly owing to the synoptic view and the good trade-off between spatial and temporal resolution, depending on the specific platform/sensor system used. In this paper, an innovative satellite-based technique for oil spill detection, based on the general robust satellite technique (RST approach, is presented. It exploits the multi-temporal analysis of data acquired in the visible channels of the Moderate Resolution Imaging Spectroradiometer (MODIS on board the Aqua satellite in order to automatically and quickly detect the presence of oil spills on the sea surface, with an attempt to minimize “false detections” caused by spurious effects associated with, for instance, cloud edges, sun/satellite geometries, sea currents, etc. The oil spill event that occurred in June 2007 off the south coast of Cyprus in the Mediterranean Sea has been considered as a test case. The resulting data, the reliability of which has been evaluated by both carrying out a confutation analysis and comparing them with those provided by the application of another independent MODIS-based method, showcase the potential of RST in identifying the presence of oil with a high level of accuracy.
Full Text Available Building extraction from high resolution remote sensing images is a hot research topic in the field of photogrammetry and remote sensing. In this article, an object-based morphological building index (OBMBI is constructed based on both image segmentation and graph-based top-hat reconstruction, and OBMBI is used for building extraction from high resolution remote sensing images. First, bidirectional mapping relationship between pixels, objects and graph-nodes are constructed. Second, the OBMBI image is built based on both graph-based top-hat reconstruction and the above mapping relationship. Third, a binary thresholding is performed on the OBMBI image, and the binary image is converted into vector format to derive the building polygons. Finally, the post-processing is made to optimize the extracted building polygons. Two images, including an aerial image and a panchromatic satellite image, are used to test both the proposed method and classic PanTex method. The experimental results suggest that our proposed method has a higher accuracy in building extraction than the classic PanTex method. On average, the correctness, the completeness and the quality of our method are respectively 9.49%, 11.26% and 14.11% better than those of the PanTex.
Chandi Witharana; Heather J. Lynch
The logistical challenges of Antarctic field work and the increasing availability of very high resolution commercial imagery have driven an interest in more efficient search and classification of remotely sensed imagery. This exploratory study employed geographic object-based analysis (GEOBIA) methods to classify guano stains, indicative of chinstrap and Adélie penguin breeding areas, from very high spatial resolution (VHSR) satellite imagery and closely examined the transferability of knowle...
Lin, C. Q.; Liu, G.; Lau, A. K. H.; Li, Y.; Li, C. C.; Fung, J. C. H.; Lao, X. Q.
Given the vast territory of China, the long-term PM2.5 trends may substantially differ among the provinces. In this study, we aim to assess the provincial PM2.5 trends in China during the past few Five-Year Plan (FYP) periods. The lack of long-term PM2.5 measurements, however, makes such assessment difficult. Satellite remote sensing of PM2.5 concentration is an important step toward filling this data gap. In this study, a PM2.5 data set was built over China at a resolution of 1 km from 2001 to 2015 using satellite remote sensing. Analyses show that the national average of PM2.5 concentration increased by 0.04 μg·m-3·yr-1 during the 10th FYP period (2001-2005) and started to decline by -0.65 μg·m-3·yr-1 and -2.33 μg·m-3·yr-1 during the 11th (2006-2010) and the 12th (2011-2015) FYP period, respectively. In addition, substantial differences in the PM2.5 trends were observed among the provinces. Provinces in the Beijing-Tianjin-Hebei (BTH) region had the largest reduction of PM2.5 concentrations during the 10th and 12th FYP period. The greatest reduction rate of PM2.5 concentration during the 10th and 12th FYP period was observed in Beijing (-3.68 μg·m-3·yr-1) and Tianjin (-6.62 μg·m-3·yr-1), respectively. In contrast, PM2.5 concentrations remained steady for provinces in eastern and southeastern China (e.g., Shanghai) during the 12th FYP period. In overall, great efforts are still required to effectively reduce the PM2.5 concentrations in future.
De Vries, Willem H; Olivier, Scot S; Pertica, Alexander J
A system for tracking objects that are in earth orbit via a constellation or network of satellites having imaging devices is provided. An object tracking system includes a ground controller and, for each satellite in the constellation, an onboard controller. The ground controller receives ephemeris information for a target object and directs that ephemeris information be transmitted to the satellites. Each onboard controller receives ephemeris information for a target object, collects images of the target object based on the expected location of the target object at an expected time, identifies actual locations of the target object from the collected images, and identifies a next expected location at a next expected time based on the identified actual locations of the target object. The onboard controller processes the collected image to identify the actual location of the target object and transmits the actual location information to the ground controller.
Pascual, Ananda; Orfila, A.; Alvarez, Alberto; Hernandez, E.; Gomis, D.; Barth, Alexander; Tintore, Joaquim
The aim of the SOFT project is to develop a new ocean forecasting system by using a combination of satellite dat, evolutionary programming and numerical ocean models. To achieve this objective two steps are proved: (1) to obtain an accurate ocean forecasting system using genetic algorithms based on satellite data; and (2) to integrate the above new system into existing deterministic numerical models. Evolutionary programming will be employed to build 'intelligent' systems that, learning form the past ocean variability and considering the present ocean state, will be able to infer near future ocean conditions. Validation of the forecast skill will be carried out by comparing the forecasts fields with satellite and in situ observations. Validation with satellite observations will provide the expected errors in the forecasting system. Validation with in situ data will indicate the capabilities of the satellite based forecast information to improve the performance of the numerical ocean models. This later validation will be accomplished considering in situ measurements in a specific oceanographic area at two different periods of time. The first set of observations will be employed to feed the hybrid systems while the second set will be used to validate the hybrid and traditional numerical model results.
Mark Nelson; Greg Liknes; Charles H. Perry
Analysis and display of forest composition, structure, and pattern provides information for a variety of assessments and management decision support. The objective of this study was to produce geospatial datasets and maps of conterminous United States forest land ownership, forest site productivity, timberland, and reserved forest land. Satellite image-based maps of...
Ou, Steve Szu-Cheng; Liou, Kuo-Nan; Wang, Xingjuan; Hansell, Richard; Lefevre, Randy; Cocks, Stephen
We undertook a new approach to investigate the aerosol indirect effect of the first kind on ice cloud formation by using available data products from the Moderate-Resolution Imaging Spectrometer (MODIS) and obtained physical understanding about the interaction between aerosols and ice clouds. Our analysis focused on the examination of the variability in the correlation between ice cloud parameters (optical depth, effective particle size, cloud water path, and cloud particle number concentration) and aerosol optical depth and number concentration that were inferred from available satellite cloud and aerosol data products. Correlation results for a number of selected scenes containing dust and ice clouds are presented, and dust aerosol indirect effects on ice clouds are directly demonstrated from satellite observations.
Balch, William; Evans, Robert; Brown, Jim; Feldman, Gene; Mcclain, Charles; Esaias, Wayne
Global pigment and primary productivity algorithms based on a new data compilation of over 12,000 stations occupied mostly in the Northern Hemisphere, from the late 1950s to 1988, were tested. The results showed high variability of the fraction of total pigment contributed by chlorophyll, which is required for subsequent predictions of primary productivity. Two models, which predict pigment concentration normalized to an attenuation length of euphotic depth, were checked against 2,800 vertical profiles of pigments. Phaeopigments consistently showed maxima at about one optical depth below the chlorophyll maxima. CZCS data coincident with the sea truth data were also checked. A regression of satellite-derived pigment vs ship-derived pigment had a coefficient of determination. The satellite underestimated the true pigment concentration in mesotrophic and oligotrophic waters and overestimated the pigment concentration in eutrophic waters. The error in the satellite estimate showed no trends with time between 1978 and 1986.
Benson, R.F.; Bauer, P.; Brace, L.H.; Carlson, H.C.; Hagen, J.; Hanson, W.B.; Hoegy, W.R.; Torr, M.R.; Wickwar, V.B.
The Atmosphere Exploere-C satellite (AE-C) is uniquely suited for correlative studies with ground-based stations because its on-board propulsion system enables a desired ground station overflight condition to be maintained for a period of several weeks. It also provides the first low-altitude (below 260 km) comparison of satellite and incoherent scatter electron and ion temperatures. More than 40 comparisons of remote and in situ measurements were made by using data from AE-C and four incoherent scatter stations (Arecibo, Chatanika, Millstone Hill, and St. Santin). The results indicate very good agreement between satellite and ground measurements of the ion temperature, the average satellite retarding potential analyzer temperatures differing from the average incoherent scatter temperatures by -2% at St. Santin, +3% at Millstone Hill, and +2% at Arecibo. The electron temperatures also agree well, the average satellite temperatures exceeding the average incoherent scatter temperatures by 3% at St. Santin, 2% at Arecibo, and 11% at Millstone Hill. Several temperature comparisons were made between AE-C and Chatanika. In spite of the highly variable ionosphere often encountered at this high-latitude location, good agreement was obtained between the in situ and remote measurements of electron and ion temperatures. Longitudinal variations are found to be very important in the comparisons of electron temperature in some locations. The agreement between the electron temperatures is considerably better than that found in some earlier comparisons involving satellities at higher altitudes
Burunkaya, M; Güler, I
In this paper, a remote-controlled and microcontroller-based cradle is designed and constructed. This system is also called Remote Control of Microcontroller-Based Infant Stimulation System or the RECOMBIS System. Cradle is an infant stimulating system that provides relaxation and sleeping for the baby. RECOMBIS system is designed for healthy full-term newborns to provide safe infant care and provide relaxation and sleeping for the baby. A microcontroller-based electronic circuit was designed and implemented for RECOMBIS system. Electromagnets were controlled by 8-bit PIC16F84 microcontroller, which is programmed using MPASM package. The system works by entering preset values from the keyboard, or pulse code modulated radio frequency remote control system. The control of the system and the motion range were tested. The test results showed that the system provided a good performance.
Full Text Available This study assesses the impact assimilating the scatterometer near-surface wind observations and total precipitable water from the SSMI, into WRF on genesis and track forecasting of four tropical cyclones (TCs. These TCs are selected to be representative of different intensity categories and basins. Impact is via a series of data denial experiments that systematically exclude the remote sensed information. Compared with the control case, in which only the final analysis atmospheric variables are used to initialize and provide the lateral boundary conditions, the data assimilation runs performed consistently better, but with very different skill levels for the different TCs. Eliassen-Palm flux analyses are employed. It is confirmed that if a polar orbital satellite footprint passes over the TC’s critical genesis region, the forecast will profit most from assimilating the remotely sensed information. If the critical genesis region lies within an interorbital gap then, regardless of how strong the TC later becomes (e.g., Katrina 2005, the improvement from assimilating near-surface winds and total precipitable water in the model prediction is severely limited. This underpins the need for a synergy of data from different scatterometers/radiometers. Other approaches are suggested to improve the accuracy in the prediction of TC genesis and tracks.
Dong, Feihong; Li, Hongjun; Gong, Xiangwu; Liu, Quan; Wang, Jingchao
A typical application scenario of remote wireless sensor networks (WSNs) is identified as an emergency scenario. One of the greatest design challenges for communications in emergency scenarios is energy-efficient transmission, due to scarce electrical energy in large-scale natural and man-made disasters. Integrated high altitude platform (HAP)/satellite networks are expected to optimally meet emergency communication requirements. In this paper, a novel integrated HAP/satellite (IHS) architecture is proposed, and three segments of the architecture are investigated in detail. The concept of link-state advertisement (LSA) is designed in a slow flat Rician fading channel. The LSA is received and processed by the terminal to estimate the link state information, which can significantly reduce the energy consumption at the terminal end. Furthermore, the transmission power requirements of the HAPs and terminals are derived using the gradient descent and differential equation methods. The energy consumption is modeled at both the source and system level. An innovative and adaptive algorithm is given for the energy-efficient path selection. The simulation results validate the effectiveness of the proposed adaptive algorithm. It is shown that the proposed adaptive algorithm can significantly improve energy efficiency when combined with the LSA and the energy consumption estimation. PMID:26404292
Full Text Available A typical application scenario of remote wireless sensor networks (WSNs is identified as an emergency scenario. One of the greatest design challenges for communications in emergency scenarios is energy-efficient transmission, due to scarce electrical energy in large-scale natural and man-made disasters. Integrated high altitude platform (HAP/satellite networks are expected to optimally meet emergency communication requirements. In this paper, a novel integrated HAP/satellite (IHS architecture is proposed, and three segments of the architecture are investigated in detail. The concept of link-state advertisement (LSA is designed in a slow flat Rician fading channel. The LSA is received and processed by the terminal to estimate the link state information, which can significantly reduce the energy consumption at the terminal end. Furthermore, the transmission power requirements of the HAPs and terminals are derived using the gradient descent and differential equation methods. The energy consumption is modeled at both the source and system level. An innovative and adaptive algorithm is given for the energy-efficient path selection. The simulation results validate the effectiveness of the proposed adaptive algorithm. It is shown that the proposed adaptive algorithm can significantly improve energy efficiency when combined with the LSA and the energy consumption estimation.
Dong, Feihong; Li, Hongjun; Gong, Xiangwu; Liu, Quan; Wang, Jingchao
A typical application scenario of remote wireless sensor networks (WSNs) is identified as an emergency scenario. One of the greatest design challenges for communications in emergency scenarios is energy-efficient transmission, due to scarce electrical energy in large-scale natural and man-made disasters. Integrated high altitude platform (HAP)/satellite networks are expected to optimally meet emergency communication requirements. In this paper, a novel integrated HAP/satellite (IHS) architecture is proposed, and three segments of the architecture are investigated in detail. The concept of link-state advertisement (LSA) is designed in a slow flat Rician fading channel. The LSA is received and processed by the terminal to estimate the link state information, which can significantly reduce the energy consumption at the terminal end. Furthermore, the transmission power requirements of the HAPs and terminals are derived using the gradient descent and differential equation methods. The energy consumption is modeled at both the source and system level. An innovative and adaptive algorithm is given for the energy-efficient path selection. The simulation results validate the effectiveness of the proposed adaptive algorithm. It is shown that the proposed adaptive algorithm can significantly improve energy efficiency when combined with the LSA and the energy consumption estimation.
Morelli, Marco; Masini, Andrea; Simeone, Emilio; Khazova, Marina
We present an innovative satellite-based UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in-vivo assessment of the erythemal effects on some volunteers having a controlled exposure to solar radiation.Both validations showed that the satellite-based UV dosimeter has a good accuracy and reliability needed for health-related applications.The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. This app will be launched on the global market by siHealth Ltd in May 2016 under the name of "HappySun" and available both for Android and for iOS devices (more info on http://www.happysun.co.uk).Extensive R&D activities are on-going for further improvement of the satellite-based UV dosimeter's accuracy.
Horion, Stéphanie Marie Anne F; Kurnik, Blaz; Barbosa, Paulo
, and therefore to better trigger timely and appropriate actions on the field. In this study, meteorological and remote sensing based drought indicators were compared over the Greater Horn of Africa in order to better understand: (i) how they depict historical drought events ; (ii) if they could be combined...... distribution. Two remote sensing based indicators were tested: the Normalized Difference Water Index (NDWI) derived from SPOT-VEGETATION and the Global Vegetation Index (VGI) derived form MERIS. The first index is sensitive to change in leaf water content of vegetation canopies while the second is a proxy...... of the amount and vigour of vegetation. For both indexes, anomalies were estimated using available satellite archives. Cross-correlations between remote sensing based anomalies and SPI were analysed for five land covers (forest, shrubland, grassland, sparse grassland, cropland and bare soil) over different...
This book describes the design and performance analysis of satnav systems, signals, and receivers. It also provides succinct descriptions and comparisons of all the world’s satnav systems. Its comprehensive and logical structure addresses all satnav signals and systems in operation and being developed. Engineering Satellite-Based Navigation and Timing: Global Navigation Satellite Systems, Signals, and Receivers provides the technical foundation for designing and analyzing satnav signals, systems, and receivers. Its contents and structure address all satnav systems and signals: legacy, modernized, and new. It combines qualitative information with detailed techniques and analyses, providing a comprehensive set of insights and engineering tools for this complex multidisciplinary field. Part I describes system and signal engineering including orbital mechanics and constellation design, signal design principles and underlying considerations, link budgets, qua tifying receiver performance in interference, and e...
Mendiguren, Gorka; Koch, Julian; Stisen, Simon
Distributed hydrological models are traditionally evaluated against discharge stations, emphasizing the temporal and neglecting the spatial component of a model. The present study widens the traditional paradigm by highlighting spatial patterns of evapotranspiration (ET), a key variable at the land-atmosphere interface, obtained from two different approaches at the national scale of Denmark. The first approach is based on a national water resources model (DK-model), using the MIKE-SHE model code, and the second approach utilizes a two-source energy balance model (TSEB) driven mainly by satellite remote sensing data. Ideally, the hydrological model simulation and remote-sensing-based approach should present similar spatial patterns and driving mechanisms of ET. However, the spatial comparison showed that the differences are significant and indicate insufficient spatial pattern performance of the hydrological model.The differences in spatial patterns can partly be explained by the fact that the hydrological model is configured to run in six domains that are calibrated independently from each other, as it is often the case for large-scale multi-basin calibrations. Furthermore, the model incorporates predefined temporal dynamics of leaf area index (LAI), root depth (RD) and crop coefficient (Kc) for each land cover type. This zonal approach of model parameterization ignores the spatiotemporal complexity of the natural system. To overcome this limitation, this study features a modified version of the DK-model in which LAI, RD and Kc are empirically derived using remote sensing data and detailed soil property maps in order to generate a higher degree of spatiotemporal variability and spatial consistency between the six domains. The effects of these changes are analyzed by using empirical orthogonal function (EOF) analysis to evaluate spatial patterns. The EOF analysis shows that including remote-sensing-derived LAI, RD and Kc in the distributed hydrological model adds
The main environmental issues affecting the broad acceptability of nuclear power plant are the emission of radioactive materials, the generation of radioactive waste, and the potential for nuclear accidents. All nuclear fission reactors, regardless of design, location, operator or regulator, have the potential to undergo catastrophic accidents involving loss of control of the reactor core, failure of safety systems and subsequent widespread fallout of hazardous fission products. Risk is the mathematical product of probability and consequences, so lowprobability and high-consequence accidents, by definition, have a high risk. NPP environment surveillance is a very important task in frame of risk assessment. Satellite remote sensing data had been applied for dosimeter levels first time for Chernobyl NPP accident in 1986. Just for a normal functioning of a nuclear power plant, multitemporal and multispectral satellite data in complementarily with field data are very useful tools for NPP environment surveillance and risk assessment. Satellite remote sensing is used as an important technology to help environmental research to support research analysis of spatio-temporal dynamics of environmental features nearby nuclear facilities. Digital processing techniques applied to several LANDSAT, MODIS and QuickBird data in synergy with in-situ data are used to assess the extent and magnitude of radiation and non-radiation effects on the water, near field soil, vegetation and air. As a test case the methodology was applied for for Nuclear Power Plant (NPP) Cernavoda, Romania. Thermal discharge from nuclear reactors cooling is dissipated as waste heat in Danube-Black -Sea Canal and Danube River. Water temperatures captured in thermal IR imagery are correlated with meteorological parameters. If during the winter thermal plume is localized to an area of a few km of NPP, the temperature difference between the plume and non-plume areas being about 1.5 oC, during summer and fall , is
used by different groups in an operational environment. 6 II. Literature Review As management science has recognized, it is not practical to separate...schedule only one satellite per set of requirements. A -4 .............. er.- Appendix B O9perational Conce~t Usin a Knowlede -Based System There are many
Capece, M.; Pavesi, B.; Tozzi, P.; Galligan, K. P.
This paper summarizes concepts developed during a study for the ESA in which the evolution of ISDN capability and the impact in the satellite land mobile area are examined. Following the progressive steps of the expected ISDN implementation and the potential market penetration, a space based system capable of satisfying particular user services classes has been investigated. The approach used is to establish a comparison between the requirements of potential mobile users and the services already envisaged by ISDN, identifying the service subclasses that might be adopted in a mobile environment through a satellite system. Two system alternatives, with different ISDN compatibility, have been identified. The first option allows a partial compatibility, by providing the central stations of the earth segment with suitable interface units. The second option permits a full integration, operating on the satellite on-board capabilities.
Abrishamkar, Farrokh; Biglieri, Ezio
Digital transmission for satellite-based land mobile communications is discussed. To satisfy the power and bandwidth limitations imposed on such systems, a combination of trellis coding and continuous-phase modulated signals are considered. Some schemes based on this idea are presented, and their performance is analyzed by computer simulation. The results obtained show that a scheme based on directional detection and Viterbi decoding appears promising for practical applications.
Hung, R. J.; Tsao, Y. D.
Rawinsonde data and geosynchronous satellite imagery were used to investigate the life cycles of St. Anthony, Minnesota's severe convective storms. It is found that the fully developed storm clouds, with overshooting cloud tops penetrating above the tropopause, collapsed about three minutes before the touchdown of the tornadoes. Results indicate that the probability of producing an outbreak of tornadoes causing greater damage increases when there are higher values of potential energy storage per unit area for overshooting cloud tops penetrating the tropopause. It is also found that there is less chance for clouds with a lower moisture content to be outgrown as a storm cloud than clouds with a higher moisture content.
Diaz, J. A.; Pieri, D. C.; Bland, G.; Fladeland, M. M.
The development of small unmanned aerial systems (sUAS) with a variety of sensor packages, enables in situ and proximal remote sensing measurements of volcanic plumes. Using Costa Rican volcanoes as a Natural Laboratory, the University of Costa Rica as host institution, in collaboration with four NASA centers, have started an initiative to develop low-cost, field-deployable airborne platforms to perform volcanic gas & ash plume research, and in-situ volcanic monitoring in general, in conjunction with orbital assets and state-of-the-art models of plume transport and composition. Several gas sensors have been deployed into the active plume of Turrialba Volcano including a miniature mass spectrometer, and an electrochemical SO2 sensor system with temperature, pressure, relative humidity, and GPS sensors. Several different airborne platforms such as manned research aircraft, unmanned aerial vehicles, tethered balloons, as well as man-portable in-situ ground truth systems are being used for this research. Remote sensing data is also collected from the ASTER and OMI spaceborne instruments and compared with in situ data. The CARTA-UAV 2013 Mission deployment and follow up measurements successfully demonstrated a path to study and visualize gaseous volcanic emissions using mass spectrometer and gas sensor based instrumentation in harsh environment conditions to correlate in situ ground/airborne data with remote sensing satellite data for calibration and validation purposes. The deployment of such technology improves on our current capabilities to detect, analyze, monitor, model, and predict hazards presented to aircraft by volcanogenic ash clouds from active and impending volcanic eruptions.
Carvalho, Gustavo A.; Minnett, Peter J.; Fleming, Lora E.; Banzon, Viva F.; Baringer, Warner
In a continuing effort to develop suitable methods for the surveillance of Harmful Algal Blooms (HABs) of Karenia brevis using satellite radiometers, a new multi-algorithm method was developed to explore whether improvements in the remote sensing detection of the Florida Red Tide was possible. A Hybrid Scheme was introduced that sequentially applies the optimized versions of two pre-existing satellite-based algorithms: an Empirical Approach (using water-leaving radiance as a function of chlorophyll concentration) and a Bio-optical Technique (using particulate backscatter along with chlorophyll concentration). The long-term evaluation of the new multi-algorithm method was performed using a multi-year MODIS dataset (2002 to 2006; during the boreal Summer-Fall periods – July to December) along the Central West Florida Shelf between 25.75°N and 28.25°N. Algorithm validation was done with in situ measurements of the abundances of K. brevis; cell counts ≥1.5×104 cells l−1 defined a detectable HAB. Encouraging statistical results were derived when either or both algorithms correctly flagged known samples. The majority of the valid match-ups were correctly identified (~80% of both HABs and non-blooming conditions) and few false negatives or false positives were produced (~20% of each). Additionally, most of the HAB-positive identifications in the satellite data were indeed HAB samples (positive predictive value: ~70%) and those classified as HAB-negative were almost all non-bloom cases (negative predictive value: ~86%). These results demonstrate an excellent detection capability, on average ~10% more accurate than the individual algorithms used separately. Thus, the new Hybrid Scheme could become a powerful tool for environmental monitoring of K. brevis blooms, with valuable consequences including leading to the more rapid and efficient use of ships to make in situ measurements of HABs. PMID:21037979
Lehahn, Yoav; d'Ovidio, Francesco; Koren, Ilan
The well-lit upper layer of the open ocean is a dynamical environment that hosts approximately half of global primary production. In the remote parts of this environment, distant from the coast and from the seabed, there is no obvious spatially fixed reference frame for describing the dynamics of the microscopic drifting organisms responsible for this immense production of organic matter—the phytoplankton. Thus, a natural perspective for studying phytoplankton dynamics is to follow the trajectories of water parcels in which the organisms are embedded. With the advent of satellite oceanography, this Lagrangian perspective has provided valuable information on different aspects of phytoplankton dynamics, including bloom initiation and termination, spatial distribution patterns, biodiversity, export of carbon to the deep ocean, and, more recently, bottom-up mechanisms that affect the distribution and behavior of higher-trophic-level organisms. Upcoming submesoscale-resolving satellite observations and swarms of autonomous platforms open the way to the integration of vertical dynamics into the Lagrangian view of phytoplankton dynamics.
Lehahn, Yoav; d'Ovidio, Francesco; Koren, Ilan
The well-lit upper layer of the open ocean is a dynamical environment that hosts approximately half of global primary production. In the remote parts of this environment, distant from the coast and from the seabed, there is no obvious spatially fixed reference frame for describing the dynamics of the microscopic drifting organisms responsible for this immense production of organic matter-the phytoplankton. Thus, a natural perspective for studying phytoplankton dynamics is to follow the trajectories of water parcels in which the organisms are embedded. With the advent of satellite oceanography, this Lagrangian perspective has provided valuable information on different aspects of phytoplankton dynamics, including bloom initiation and termination, spatial distribution patterns, biodiversity, export of carbon to the deep ocean, and, more recently, bottom-up mechanisms that affect the distribution and behavior of higher-trophic-level organisms. Upcoming submesoscale-resolving satellite observations and swarms of autonomous platforms open the way to the integration of vertical dynamics into the Lagrangian view of phytoplankton dynamics.
Muzylev, Eugene; Uspensky, Alexander; Startseva, Zoya; Volkova, Elena; Kukharsky, Alexander; Uspensky, Sergey
The model of vertical water and heat transfer in the "soil-vegetation-atmosphere" system (SVAT) for vegetation covered territory has been developed, allowing assimilating satellite remote sensing data on land surface condition as well as accounting for heterogeneities of vegetation and meteorological characteristics. The model provides the calculation of water and heat balance components (such as evapotranspiration Ev, soil water content W, sensible and latent heat fluxes and others ) as well as vertical soil moisture and temperature distributions, temperatures of soil surface and foliage, land surface brightness temperature for any time interval within vegetation season. To describe the landscape diversity soil constants and leaf area index LAI, vegetation cover fraction B, and other vegetation characteristics are used. All these values are considered to be the model parameters. Territory of Kursk region with square about 15 thousands km2 situated in the Black Earth zone of Central Russia was chosen for investigation. Satellite-derived estimates of land surface characteristics have been constructed under cloud-free condition basing AVHRR/NOAA, MODIS/EOS Terra and EOS Aqua, SEVIRI/Meteosat-8, -9 data. The developed technologies of AVHRR data thematic processing have been refined providing the retrieval of surface skin brightness temperature Tsg, air foliage temperature Ta, efficient surface temperature Ts.eff and emissivity E, as well as derivation of vegetation index NDVI, B, and LAI. The linear regression estimators for Tsg, Ta and LAI have been built using representative training samples for 2003-2009 vegetation seasons. The updated software package has been applied for AVHRR data thematic processing to generate named remote sensing products for various dates of the above vegetation seasons. The error statistics of Ta, Ts.eff and Тsg derivation has been investigated for various samples using comparison with in-situ measurements that has given RMS errors in the
Zhao, Y.; Wei, P.; Zhu, H.; Xing, B.
The Bohai Sea is the inland sea with the highest latitude in China. In winter, the phenomenon of freezing occurs in the Bohai Sea due to frequent cold wave influx. According to historical records, there have been three serious ice packs in the Bohai Sea in the past 50 years which caused heavy losses to our economy. Therefore, it is of great significance to monitor the drift of sea ice and sea ice in the Bohai Sea. The GF4 image has the advantages of short imaging time and high spatial resolution. Based on the GF4 satellite images, the three methods of SIFT (Scale invariant feature - the transform and Scale invariant feature transform), MCC (maximum cross-correlation method) and sift combined with MCC are used to monitor sea ice drift and calculate the speed and direction of sea ice drift, the three calculation results are compared and analyzed by using expert interpretation and historical statistical data to carry out remote sensing monitoring of sea ice drift results. The experimental results show that the experimental results of the three methods are in accordance with expert interpretation and historical statistics. Therefore, the GF4 remote sensing satellite images have the ability to monitor sea ice drift and can be used for drift monitoring of sea ice in the Bohai Sea.
Smith, Laurence C.
The growing availability of multi-temporal satellite data has increased opportunities for monitoring large rivers from space. A variety of passive and active sensors operating in the visible and microwave range are currently operating, or planned, which can estimate inundation area and delineate flood boundaries. Radar altimeters show great promise for directly measuring stage variation in large rivers. It also appears to be possible to obtain estimates of river discharge from space, using ground measurements and satellite data to construct empirical curves that relate water surface area to discharge. Extrapolation of these curves to ungauged sites may be possible for the special case of braided rivers.Where clouds, trees and floating vegetation do not obscure the water surface, high-resolution visible/infrared sensors provide good delineation of inundated areas. Synthetic aperture radar (SAR) sensors can penetrate clouds and can also detect standing water through emergent aquatic plants and forest canopies. However, multiple frequencies and polarizations are required for optimal discrimination of various inundated vegetation cover types. Existing single-polarization, fixed-frequency SARs are not sufficient for mapping inundation area in all riverine environments. In the absence of a space-borne multi-parameter SAR, a synergistic approach using single-frequency, fixed-polarization SAR and visible/infrared data will provide the best results over densely vegetated river floodplains.
Bolten, J. D.; Mohammed, I. N.; Srinivasan, R.; Lakshmi, V.
Better understanding of the hydrological cycle of the Lower Mekong River Basin (LMRB) and addressing the value-added information of using remote sensing data on the spatial variability of soil moisture over the Mekong Basin is the objective of this work. In this work, we present the development and assessment of the LMRB (drainage area of 495,000 km2) Soil and Water Assessment Tool (SWAT). The coupled model framework presented is part of SERVIR, a joint capacity building venture between NASA and the U.S. Agency for International Development, providing state-of-the-art, satellite-based earth monitoring, imaging and mapping data, geospatial information, predictive models, and science applications to improve environmental decision-making among multiple developing nations. The developed LMRB SWAT model enables the integration of satellite-based daily gridded precipitation, air temperature, digital elevation model, soil texture, and land cover and land use data to drive SWAT model simulations over the Lower Mekong River Basin. The LMRB SWAT model driven by remote sensing climate data was calibrated and verified with observed runoff data at the watershed outlet as well as at multiple sites along the main river course. Another LMRB SWAT model set driven by in-situ climate observations was also calibrated and verified to streamflow data. Simulated soil moisture estimates from the two models were then examined and compared to a downscaled Soil Moisture Active Passive Sensor (SMAP) 36 km radiometer products. Results from this work present a framework for improving SWAT performance by utilizing a downscaled SMAP soil moisture products used for model calibration and validation. Index Terms: 1622: Earth system modeling; 1631: Land/atmosphere interactions; 1800: Hydrology; 1836 Hydrological cycles and budgets; 1840 Hydrometeorology; 1855: Remote sensing; 1866: Soil moisture; 6334: Regional Planning
Myint, S.W.; Yuan, M.; Cerveny, R.S.; Giri, C.
Remote sensing of a natural disaster's damage offers an exciting backup and/or alternative to traditional means of on-site damage assessment. Although necessary for complete assessment of damage areas, ground-based damage surveys conducted in the aftermath of natural hazard passage can sometimes be potentially complicated due to on-site difficulties (e.g., interaction with various authorities and emergency services) and hazards (e.g., downed power lines, gas lines, etc.), the need for rapid mobilization (particularly for remote locations), and the increasing cost of rapid physical transportation of manpower and equipment. Satellite image analysis, because of its global ubiquity, its ability for repeated independent analysis, and, as we demonstrate here, its ability to verify on-site damage assessment provides an interesting new perspective and investigative aide to researchers. Using one of the strongest tornado events in US history, the 3 May 1999 Oklahoma City Tornado, as a case example, we digitized the tornado damage path and co-registered the damage path using pre- and post-Landsat Thematic Mapper image data to perform a damage assessment. We employed several geospatial approaches, specifically the Getis index, Geary's C, and two lacunarity approaches to categorize damage characteristics according to the original Fujita tornado damage scale (F-scale). Our results indicate strong relationships between spatial indices computed within a local window and tornado F-scale damage categories identified through the ground survey. Consequently, linear regression models, even incorporating just a single band, appear effective in identifying F-scale damage categories using satellite imagery. This study demonstrates that satellite-based geospatial techniques can effectively add spatial perspectives to natural disaster damages, and in particular for this case study, tornado damages.
Schwandner, Florian M.; Miller, Charles E.; Duren, Riley M.; Natraj, Vijay; Eldering, Annmarie; Gunson, Michael R.; Crisp, David
Atmospheric CO2 budgets are controlled by the strengths, as well as the spatial and temporal variabilities of CO2 sources and sinks. Natural CO2 sources and sinks are dominated by the vast areas of the oceans and the terrestrial biosphere. In contrast, anthropogenic and geogenic CO2 sources are dominated by distributed area and point sources, which may constitute as much as 70% of anthropogenic (e.g., Duren & Miller, 2012), and over 80% of geogenic emissions (Burton et al., 2013). Comprehensive assessments of CO2 budgets necessitate robust and highly accurate satellite remote sensing strategies that address the competing and often conflicting requirements for sampling over disparate space and time scales. Spatial variability: The spatial distribution of anthropogenic sources is dominated by patterns of production, storage, transport and use. In contrast, geogenic variability is almost entirely controlled by endogenic geological processes, except where surface gas permeability is modulated by soil moisture. Satellite remote sensing solutions will thus have to vary greatly in spatial coverage and resolution to address distributed area sources and point sources alike. Temporal variability: While biogenic sources are dominated by diurnal and seasonal patterns, anthropogenic sources fluctuate over a greater variety of time scales from diurnal, weekly and seasonal cycles, driven by both economic and climatic factors. Geogenic sources typically vary in time scales of days to months (geogenic sources sensu stricto are not fossil fuels but volcanoes, hydrothermal and metamorphic sources). Current ground-based monitoring networks for anthropogenic and geogenic sources record data on minute- to weekly temporal scales. Satellite remote sensing solutions would have to capture temporal variability through revisit frequency or point-and-stare strategies. Space-based remote sensing offers the potential of global coverage by a single sensor. However, no single combination of orbit
Gandhinagar Ekanthappa, Rudresh; Escobar, Rodrigo; Matevossian, Achot; Akopian, David
Electrical and computer engineering graduates need practical working skills with real-world electronic devices, which are addressed to some extent by hands-on laboratories. Deployment capacity of hands-on laboratories is typically constrained due to insufficient equipment availability, facility shortages, and lack of human resources for in-class support and maintenance. At the same time, at many sites, existing experimental systems are usually underutilized due to class scheduling bottlenecks. Nowadays, online education gains popularity and remote laboratories have been suggested to broaden access to experimentation resources. Remote laboratories resolve many problems as various costs can be shared, and student access to instrumentation is facilitated in terms of access time and locations. Labs are converted to homeworks that can be done without physical presence in laboratories. Even though they are not providing full sense of hands-on experimentation, remote labs are a viable alternatives for underserved educational sites. This paper studies remote modality of USRP-based radio-communication labs offered by National Instruments (NI). The labs are offered to graduate and undergraduate students and tentative assessments support feasibility of remote deployments.
Saito, K.; Brown, D.; Spence, R.; Chenvidyakarn, T.; Adams, B.; Bevington, J.; Platt, S.; Chuenpagdee, R.; Juntarashote, K.; Khan, A.
The use of high-resolution optical satellite images is being investigated for evaluating and monitoring recovery after natural disasters. Funded by EPSRC, UK, the aim of the RECOVERY project is to develop indicators of recovery that can exploit the wealth of data now available, including those from satellite imagery, internet-based statistics and advanced field survey techniques. The final output will be a set of guidelines that suggests how remote sensing can be used to help monitor and evaluate the recovery process after natural disasters. The final guideline that will be produced at the end of the two year project, which started in February 2008, will be freely available to aid agencies and anyone that is interested. Currently there is no agreed standard approach for evaluating the effectiveness of recovery aid, although international frameworks such as PDNA (Post-Disaster Needs Assessment, United Nations Development Program, European Commission and World Bank) is currently being developed, and TRIAMS (Tsunami Recovery and Impact Assessment and Monitoring System, by UNDP and WHO) is being implemented to monitor the recovery from the Indian Ocean Tsunami. The RECOVERY project consists of three phases. Phase 1 was completed by September 2008 and focused on user needs survey, developing the recovery indicators and satellite image data identification/acquisition. The user needs survey was conducted to identify whether there were any indicators that the aid community would like to see prioritised. The survey result suggested that most indicators are equally important. Based on this result and also referring to the TRIAMS framework, a comprehensive list of indicators were developed which belong to six large categories, i.e. housing, infrastructure, services, livelihood, environment, social/security, risk reduction. For the RECOVERY project, two case study sites have been identified, i.e. the village of Baan Nam Khem on the west coast of Thailand, which was heavily
Leifer, I.; Clark, R.; Jones, C.; Holt, B.; Svejkovsky, J.; Swayze, G.
The vast, persistent, and unconstrained oil release from the DeepWater Horizon (DWH) challenged the spill response, which required accurate quantitative oil assessment at synoptic and operational scales. Experienced observers are the mainstay of oil spill response. Key limitations are weather, scene illumination geometry, and few trained observers, leading to potential observer bias. Aiding the response was extensive passive and active satellite and airborne remote sensing, including intelligent system augmentation, reviewed herein. Oil slick appearance strongly depends on many factors like emulsion composition and scene geometry, yielding false positives and great thickness uncertainty. Oil thicknesses and the oil to water ratios for thick slicks were derived quantitatively with a new spectral library approach based on the shape and depth of spectral features related to C-H vibration bands. The approach used near infrared, imaging spectroscopy data from the AVIRIS (Airborne Visual/InfraRed Imaging Spectrometer) instrument on the NASA ER-2 stratospheric airplane. Extrapolation to the total slick used MODIS satellite visual-spectrum broadband data, which observes sunglint reflection from surface slicks; i.e., indicates the presence of oil and/or surfactant slicks. Oil slick emissivity is less than seawater's allowing MODIS thermal infrared (TIR) nighttime identification; however, water temperature variations can cause false positives. Some strong emissivity features near 6.7 and 9.7 ??m could be analyzed as for the AVIRIS short wave infrared features, but require high spectral resolution data. TIR spectral trends can allow fresh/weathered oil discrimination. Satellite Synthetic Aperture Radar (SSAR) provided synoptic data under all-sky conditions by observing oil dampening of capillary waves; however, SSAR typically cannot discriminate thick from thin oil slicks. Airborne UAVSAR's significantly greater signal-to-noise ratio and fine spatial resolution allowed
Oreggioni Weiberlen, Fiorella; Báez Benítez, Julián
Satellite-based precipitation estimates represent a potential alternative source of input data in a plethora of meteorological and hydrological applications, especially in regions characterized by a low density of rain gauge stations. Paraguay provides a good example of a case where the use of satellite-based precipitation could be advantageous. This study aims to evaluate the version 7 of the Tropical Rainfall Measurement Mission Multi-Satellite Precipitation Analysis (TMPA V7; 3B42 V7) and the version 1.0 of the purely satellite-based product of the Climate Prediction Center Morphing Technique (CMORPH RAW) through their comparison with daily in situ precipitation measurements from 1998 to 2012 over Paraguay. The statistical assessment is conducted with several commonly used indexes. Specifically, to evaluate the accuracy of daily precipitation amounts, mean error (ME), root mean square error (RMSE), BIAS, and coefficient of determination (R 2) are used, and to analyze the capability to correctly detect different precipitation intensities, false alarm ratio (FAR), frequency bias index (FBI), and probability of detection (POD) are applied to various rainfall rates (0, 0.1, 0.5, 1, 2, 5, 10, 20, 40, 60, and 80 mm/day). Results indicate that TMPA V7 has a better performance than CMORPH RAW over Paraguay. TMPA V7 has higher accuracy in the estimation of daily rainfall volumes and greater precision in the detection of wet days (> 0 mm/day). However, both satellite products show a lower ability to appropriately detect high intensity precipitation events.
Zasetsky, A. Y.; Khalizov, A.; Sloan, J.
Observations of broadband Infrared satellites such as ILAS-II (Ministry of the Environment, Japan, launched 14 December 2002) and SciSat-1 (Canadian Space Agency, launched 12 August 2003) can provide details of the chemical composition and particle size of atmospheric aerosols by direct inversion without recourse to models. During the past decade, we have developed mathematical methods to achieve this inversion by working with FTIR observations of model atmospheric aerosols in cryogenic flowtubes. More recently, we have converted these to operational algorithms for use in the above missions. In this presentation, we will briefly outline these procedures and illustrate their capabilities using laboratory data. These laboratory results show that the chemical compositions, phases and sizes of ensembles of particles can be obtained simultaneously using these procedures. We will also report chemical and microphysical properties of lower stratospheric clouds and aerosols derived by applying these procedures to observations from space.
Full Text Available Snow on Antarctic sea ice plays a key role for sea ice physical processes and complicates retrieval of sea ice thickness using altimetry. Current methods of snow depth retrieval are based on satellite microwave radiometry, which perform best for dry, homogeneous snow packs on level sea ice. We introduce an alternative approach based on in-situ measurements of total (sea ice plus snow freeboard and snow depth, which we use to compute snow depth on sea ice from Ice, Cloud, and land Elevation Satellite (ICESat total freeboard observations. We compare ICESat snow depth for early winter and spring of the years 2004 through 2006 with the Advanced Scanning Microwave Radiometer aboard EOS (AMSR-E snow depth product. We find ICESat snow depths agree more closely with ship-based visual and air-borne snow radar observations than AMSR-E snow depths. We obtain average modal and mean ICESat snow depths, which exceed AMSR-E snow depths by 5–10 cm in winter and 10–15 cm in spring. We observe an increase in ICESat snow depth from winter to spring for most Antarctic regions in accordance with ground-based observations, in contrast to AMSR-E snow depths, which we find to stay constant or to decrease. We suggest satellite laser altimetry as an alternative method to derive snow depth on Antarctic sea ice, which is independent of snow physical properties.
Lopez Valencia, Oliver Miguel
Advances in multi-satellite based observations of the earth system have provided the capacity to retrieve information across a wide-range of land surface hydrological components and provided an opportunity to characterize terrestrial processes from a completely new perspective. Given the spatial advantage that space-based observations offer, several regional-to-global scale products have been developed, offering insights into the multi-scale behaviour and variability of hydrological states and fluxes. However, one of the key challenges in the use of satellite-based products is characterizing the degree to which they provide realistic and representative estimates of the underlying retrieval: that is, how accurate are the hydrological components derived from satellite observations? The challenge is intrinsically linked to issues of scale, since the availability of high-quality in-situ data is limited, and even where it does exist, is generally not commensurate to the resolution of the satellite observation. Basin-scale studies have shown considerable variability in achieving water budget closure with any degree of accuracy using satellite estimates of the water cycle. In order to assess the suitability of this type of approach for evaluating hydrological observations, it makes sense to first test it over environments with restricted hydrological inputs, before applying it to more hydrological complex basins. Here we explore the concept of hydrological consistency, i.e. the physical considerations that the water budget impose on the hydrologic fluxes and states to be temporally and spatially linked, to evaluate the reproduction of a set of large-scale evaporation (E) products by using a combination of satellite rainfall (P) and Gravity Recovery and Climate Experiment (GRACE) observations of storage change, focusing on arid and semi-arid environments, where the hydrological flows can be more realistically described. Our results indicate no persistent hydrological
Li, Jie; Zhu, Lingling; Cao, Fubin
To solve the problem that the remote sensing image segmentation speed is slow and the real-time performance is poor, this paper studies the method of remote sensing image segmentation based on Hadoop platform. On the basis of analyzing the structural characteristics of Hadoop cloud platform and its component MapReduce programming, this paper proposes a method of image segmentation based on the combination of OpenCV and Hadoop cloud platform. Firstly, the MapReduce image processing model of Hadoop cloud platform is designed, the input and output of image are customized and the segmentation method of the data file is rewritten. Then the Mean Shift image segmentation algorithm is implemented. Finally, this paper makes a segmentation experiment on remote sensing image, and uses MATLAB to realize the Mean Shift image segmentation algorithm to compare the same image segmentation experiment. The experimental results show that under the premise of ensuring good effect, the segmentation rate of remote sensing image segmentation based on Hadoop cloud Platform has been greatly improved compared with the single MATLAB image segmentation, and there is a great improvement in the effectiveness of image segmentation.
Seepers, Robert Mark; Wang, Wenjin; de Haan, Gerard; Sourdis, Ioannis; Strydis, Christos
The time interval between consecutive heartbeats (interpulse interval, IPI) has previously been suggested for securing mobile-health solutions. This time interval is known to contain a degree of randomness, permitting the generation of a time- and person-specific identifier. It is commonly assumed that only devices trusted by a person can make physical contact with him/her, and that this physical contact allows each device to generate a similar identifier based on its own cardiac recordings. Under these conditions, the identifiers generated by different trusted devices can facilitate secure authentication. Recently, a wide range of techniques have been proposed for measuring heartbeats remotely, a prominent example of which is remote photoplethysmography (rPPG). These techniques may pose a significant threat to heartbeat-based security, as an adversary may pretend to be a trusted device by generating a similar identifier without physical contact, thus bypassing one of the core security conditions. In this paper, we assess the feasibility of such remote attacks using state-of-the-art rPPG methods. Our evaluation shows that rPPG has similar accuracy as contact PPG and, thus, forms a substantial threat to heartbeat-based-security systems that permit trusted devices to obtain their identifiers from contact PPG recordings. Conversely, rPPG cannot obtain an accurate representation of an identifier generated from electrical cardiac signals, making the latter invulnerable to state-of-the-art remote attacks.
Full Text Available In this review paper we present geographical, ecological and historical aspects of Southeast Asia from the perspective of forest degradation monitoring and critically discuss available approaches for large area forest degradation monitoring with satellite remote sensing data at high to medium spatial resolution (5–30 m. Several authors have achieved promising results in geographically limited areas within Southeast Asia using automated detection algorithms. However, the application of automated methods to large area assessments remains a major challenge. To-date, nearly all large area assessments of forest degradation in the region have included a strong visual interpretation component. We conclude that due to the variety of forest types and forest disturbance levels, as well as the variable image acquisition conditions in Southeast Asia, it is unlikely that forest degradation monitoring can be conducted throughout the region using a single automated approach with currently available remote sensing data. The provision of regionally consistent information on forest degradation from satellite remote sensing data remains therefore challenging. However, the expected increase in observation frequency in the near future (due to Landsat 8 and Sentinel-2 satellites may lead to the desired improvement in data availability and enable consistent and robust regional forest degradation monitoring in Southeast Asia. Keywords: Tropical forest disturbance, Selective logging, Shifting cultivation, Satellite data, Indochina peninsula, Maritime continent
Full Text Available This paper describes the use of machine learning methods to build a decision support system for predicting the distribution of coastal ocean algal blooms based on remote sensing data in Monterey Bay. This system can help scientists obtain prior information in a large ocean region and formulate strategies for deploying robots in the coastal ocean for more detailed in situ exploration. The difficulty is that there are insufficient in situ data to create a direct statistical machine learning model with satellite data inputs. To solve this problem, we built a Random Forest model using MODIS and MERIS satellite data and applied a threshold filter to balance the training inputs and labels. To build this model, several features of remote sensing satellites were tested to obtain the most suitable features for the system. After building the model, we compared our random forest model with previous trials based on a Support Vector Machine (SVM using satellite data from 221 days, and our approach performed significantly better. Finally, we used the latest in situ data from a September 2014 field experiment to validate our model.
Piffl, V.; Pichal, J.
The following topics were dealt with: (i) Current status of the Garching/Greifswald connection; (ii) Remote participation across national boundaries; (iii) The TEC approach to a remote control room at TEXTOR; (iv) Uniform data access for remote participation; (v) Remote participation in the US transport code collaboration; (vi) Client-server for remote collaboration and remote invocation of analysis applications and application to the national transport code; (vii) Remote collaboration and data access at the DIII-D national fusion facility; (viii) The collaboration for support of scientific research; and (ix) JET and remote participation. (P.A.)
Piffl, V; Pichal, J [eds.
The following topics were dealt with: (i) Current status of the Garching/Greifswald connection; (ii) Remote participation across national boundaries; (iii) The TEC approach to a remote control room at TEXTOR; (iv) Uniform data access for remote participation; (v) Remote participation in the US transport code collaboration; (vi) Client-server for remote collaboration and remote invocation of analysis applications and application to the national transport code; (vii) Remote collaboration and data access at the DIII-D national fusion facility; (viii) The collaboration for support of scientific research; and (ix) JET and remote participation. (P.A.)
Full Text Available Water level (WL and water volume (WV of surface-water bodies are among the most crucial variables used in water-resources assessment and management. They fluctuate as a result of climatic forcing, and they are considered as indicators of climatic impacts on water resources. Quantifying riverine WL and WV, however, usually requires the availability of timely and continuous in situ data, which could be a challenge for rivers in remote regions, including the Mekong River basin. As one of the most developed rivers in the world, with more than 20 dams built or under construction, Mekong River is in need of a monitoring system that could facilitate basin-scale management of water resources facing future climate change. This study used spaceborne sensors to investigate two dams in the upper Mekong River, Xiaowan and Jinghong Dams within China, to examine river flow dynamics after these dams became operational. We integrated multi-mission satellite radar altimetry (RA, Envisat and Jason-2 and Landsat-5/-7/-8 Thematic Mapper (TM/Enhanced Thematic Mapper plus (ETM+/Operational Land Imager (OLI optical remote sensing (RS imageries to construct composite WL time series with enhanced spatial resolutions and substantially extended WL data records. An empirical relationship between WL variation and water extent was first established for each dam, and then the combined long-term WL time series from Landsat images are reconstructed for the dams. The R2 between altimetry WL and Landsat water area measurements is >0.95. Next, the Tropical Rainfall Measuring Mission (TRMM data were used to diagnose and determine water variation caused by the precipitation anomaly within the basin. Finally, the impact of hydrologic dynamics caused by the impoundment of the dams is assessed. The discrepancy between satellite-derived WL and available in situ gauge data, in term of root-mean-square error (RMSE is at 2–5 m level. The estimated WV variations derived from combined RA
P. M. E. Décréau
latitudes, is radiating radio waves. The radio waves are issued from multiple sources of small size, each related to a given fs series and radiating inside a beam of narrow cone angle, referred to as a beamlet. The beamlets illuminate different satellites simultaneously, at different characteristic fs values, according to the latitude at which the satellite is placed. Second, when an observing satellite moves away from its assumed source region (the plasmapause surface, it is illuminated by several beamlets, issued from nearby sources with characteristic fs values close to each other. The addition of radio waves blurs the spectra of the overall received electric field. It can move the signal peaks such that their position fs satisfiesfs = (n+α df, with 0 < α < 1. These findings open new perspectives for the interpretation of NTC events displaying harmonic signatures.
Chen, Gongbo; Knibbs, Luke D; Zhang, Wenyi; Li, Shanshan; Cao, Wei; Guo, Jianping; Ren, Hongyan; Wang, Boguang; Wang, Hao; Williams, Gail; Hamm, N A S; Guo, Yuming
PM 1 might be more hazardous than PM 2.5 (particulate matter with an aerodynamic diameter ≤ 1 μm and ≤2.5 μm, respectively). However, studies on PM 1 concentrations and its health effects are limited due to a lack of PM 1 monitoring data. To estimate spatial and temporal variations of PM 1 concentrations in China during 2005-2014 using satellite remote sensing, meteorology, and land use information. Two types of Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6 aerosol optical depth (AOD) data, Dark Target (DT) and Deep Blue (DB), were combined. Generalised additive model (GAM) was developed to link ground-monitored PM 1 data with AOD data and other spatial and temporal predictors (e.g., urban cover, forest cover and calendar month). A 10-fold cross-validation was performed to assess the predictive ability. The results of 10-fold cross-validation showed R 2 and Root Mean Squared Error (RMSE) for monthly prediction were 71% and 13.0 μg/m 3 , respectively. For seasonal prediction, the R 2 and RMSE were 77% and 11.4 μg/m 3 , respectively. The predicted annual mean concentration of PM 1 across China was 26.9 μg/m 3 . The PM 1 level was highest in winter while lowest in summer. Generally, the PM 1 levels in entire China did not substantially change during the past decade. Regarding local heavy polluted regions, PM 1 levels increased substantially in the South-Western Hebei and Beijing-Tianjin region. GAM with satellite-retrieved AOD, meteorology, and land use information has high predictive ability to estimate ground-level PM 1 . Ambient PM 1 reached high levels in China during the past decade. The estimated results can be applied to evaluate the health effects of PM 1 . Copyright © 2017 Elsevier Ltd. All rights reserved.
Marlow, W. A.; Cahoy, K.; Males, J.; Carlton, A.; Yoon, H.
Real-time observation and monitoring of geostationary (GEO) satellites with ground-based imaging systems would be an attractive alternative to fielding high cost, long lead, space-based imagers, but ground-based observations are inherently limited by atmospheric turbulence. Adaptive optics (AO) systems are used to help ground telescopes achieve diffraction-limited seeing. AO systems have historically relied on the use of bright natural guide stars or laser guide stars projected on a layer of the upper atmosphere by ground laser systems. There are several challenges with this approach such as the sidereal motion of GEO objects relative to natural guide stars and limitations of ground-based laser guide stars; they cannot be used to correct tip-tilt, they are not point sources, and have finite angular sizes when detected at the receiver. There is a difference between the wavefront error measured using the guide star compared with the target due to cone effect, which also makes it difficult to use a distributed aperture system with a larger baseline to improve resolution. Inspired by previous concepts proposed by A.H. Greenaway, we present using a space-based laser guide starprojected from a satellite orbiting the Earth. We show that a nanosatellite-based guide star system meets the needs for imaging GEO objects using a low power laser even from 36,000 km altitude. Satellite guide star (SGS) systemswould be well above atmospheric turbulence and could provide a small angular size reference source. CubeSatsoffer inexpensive, frequent access to space at a fraction of the cost of traditional systems, and are now being deployed to geostationary orbits and on interplanetary trajectories. The fundamental CubeSat bus unit of 10 cm cubed can be combined in multiple units and offers a common form factor allowing for easy integration as secondary payloads on traditional launches and rapid testing of new technologies on-orbit. We describe a 6U CubeSat SGS measuring 10 cm x 20 cm x
Brandt, Martin Stefan; Mbow, Cheikh; Diouf, Abdoul A.
After a dry period with prolonged droughts in the 1970s and 1980s, recent scientific outcome suggests that the decades of abnormally dry conditions in the Sahel have been reversed by positive anomalies in rainfall. Various remote sensing studies observed a positive trend in vegetation greenness...... over the last decades which is known as the re-greening of the Sahel. However, little investment has been made in including long-term ground-based data collections to evaluate and better understand the biophysical mechanisms behind these findings. Thus, deductions on a possible increment in biomass...... remain speculative. Our aim is to bridge these gaps and give specifics on the biophysical background factors of the re-greening Sahel. Therefore, a trend analysis was applied on long time series (1987-2013) of satellite-based vegetation and rainfall data, as well as on ground-observations of leaf biomass...
Kimijiama, S; Nagai, M
In Greater Mekong Sub-region (GMS), economic liberalization and deregulation facilitated by GMS Regional Economic Corporation Program (GMS-ECP) has triggered urbanization in the region. However, the urbanization rate and its linkage to socio-economic activities are ambiguous. The objectives of this paper are to: (a) determine the changes in urban area from 1972 to 2013 using remote sensing data, and (b) analyse the relationships between urbanization with respect to socio-economic activities in central Laos. The study employed supervised classification and human visible interpretation to determine changes in urbanization rate. Regression analysis was used to analyze the correlation between the urbanization rate and socio-economic variables. The result shows that the urban area increased significantly from 1972 to 2013. The socio-economic variables such as school enrollment, labour force, mortality rate, water source and sanitation highly correlated with the rate of urbanization during the period. The study concluded that identifying the highly correlated socio-economic variables with urbanization rate could enable us to conduct a further urbanization simulation. The simulation helps in designing policies for sustainable development
Die, Hu; Lei, Zhang; Hongbin, Wang
In this study, Aerosol Optical Depth (AOD) at 550nm from the MODIS sensor on board the Terra/Aqua satellites were compared with sun photometer (CE-318) measurements from 11 AERONET stations in China. The average correlation coefficient (R) value from the AOD product, using the Aqua-MODIS Deep Blue algorithm, in the Hexi Corridor was 0.67. The MODIS Dark Target algorithm AOD product is superior to Deep Blue algorithm AOD products in SACOL of the Semi-arid regions of the Loess Plateau. These two kinds of algorithm are not applicable to sites in Lanzhou city. The average R value of Dark Target algorithm AOD MODIS products is 0.91 for Terra and 0.88 for Aqua in the eastern part of China. According to the analysis of spatial and temporal characteristics of the two MODIS AOD products in China, high value areas are mainly distributed in the southern part of Xinjiang (0.5∼0.8), Sichuan Basin (0.8∼0.9), North China (0.6∼0.8) and the middle and lower reaches of the Changjiang River (0.8∼1.0). The Deep Blue algorithm for Aqua-MODIS is a good supplement for the retrieval of AOD above bright surfaces of deserts in Northwest China
Rokhmana, Catur Aries; Andaru, Ruli
Indonesia is located in an area prone to disasters, which are various kinds of natural disasters happen. In disaster management, the geoinformation data are needed to be able to evaluate the impact area. The UAV (Unmanned Aerial Vehicle)-Based remote sensing technology is a good choice to produce a high spatial resolution of less than 15 cm, while the current resolution of the satellite imagery is still greater than 50 cm. This paper shows some technical notes that should be considered when using UAV-Based remote sensing system in post disaster for rapid assessment. Some cases are Aceh Earthquake in years 2013 for seeing infrastructure damages, Banjarnegara landslide in year 2014 for seeing the impact; and Kelud volcano eruption in year 2014 for seeing the impact and volumetric material calculation. The UAV-Based remote sensing system should be able to produce the Orthophoto image that can provide capabilities for visual interpretation the individual damage objects, and the changes situation. Meanwhile the DEM (digital Elevation model) product can derive terrain topography, and volumetric calculation with accuracy 3-5 pixel or sub-meter also. The UAV platform should be able for working remotely and autonomously in dangerous area and limited infrastructures. In mountainous or volcano area, an unconventional flight plan should implemented. Unfortunately, not all impact can be seen from above such as wall crack, some parcel boundaries, and many objects that covered by others higher object. The previous existing geoinformation data are also needed to be able to evaluate the change detection automatically.
Sedaghat, Amin; Mohammadi, Nazila
Local feature detectors are widely used in many photogrammetry and remote sensing applications. The quantity and distribution of the local features play a critical role in the quality of the image matching process, particularly for multi-sensor high resolution remote sensing image registration. However, conventional local feature detectors cannot extract desirable matched features either in terms of the number of correct matches or the spatial and scale distribution in multi-sensor remote sensing images. To address this problem, this paper proposes a novel method for uniform and robust local feature extraction for remote sensing images, which is based on a novel competency criterion and scale and location distribution constraints. The proposed method, called uniform competency (UC) local feature extraction, can be easily applied to any local feature detector for various kinds of applications. The proposed competency criterion is based on a weighted ranking process using three quality measures, including robustness, spatial saliency and scale parameters, which is performed in a multi-layer gridding schema. For evaluation, five state-of-the-art local feature detector approaches, namely, scale-invariant feature transform (SIFT), speeded up robust features (SURF), scale-invariant feature operator (SFOP), maximally stable extremal region (MSER) and hessian-affine, are used. The proposed UC-based feature extraction algorithms were successfully applied to match various synthetic and real satellite image pairs, and the results demonstrate its capability to increase matching performance and to improve the spatial distribution. The code to carry out the UC feature extraction is available from href="https://www.researchgate.net/publication/317956777_UC-Feature_Extraction.
Varnavas, Kosta; Sims, Herb
With the explosion of the CubeSat, small sat, and nanosat markets, the need for a robust, highly capable, yet affordable satellite base station, capable of telemetry capture and relay, is significant. The Programmable Ultra-Lightweight System Adaptable Radio (PULSAR) is NASA Marshall Space Flight Center's (MSFC's) software-defined digital radio, developed with previous Technology Investment Programs and Technology Transfer Office resources. The current PULSAR will have achieved a Technology Readiness Level-6 by the end of FY 2014. The extensibility of the PULSAR will allow it to be adapted to perform the tasks of a mobile base station capable of commanding, receiving, and processing satellite, rover, or planetary probe data streams with an appropriate antenna.
Roelfsema, C. M.; Phinn, S. R.; Lyons, M. B.; Kovacs, E.; Saunders, M. I.; Leon, J. X.
Corals and Submerged Aquatic Vegetation (SAV) are typically found in highly dynamic environments where the magnitude and types of physical and biological processes controlling their distribution, diversity and function changes dramatically. Recent advances in the types of satellite image data and the length of their archives that are available globally, coupled with new techniques for extracting environmental information from these data sets has enabled significant advances to be made in our ability to map and monitor coral and SAV environments. Object Based Image Analysis techniques are one of the most significant advances in information extraction techniques for processing images to deliver environmental information at multiple spatial scales. This poster demonstrates OBIA applied to high spatial resolution satellite image data to map and monitor coral and SAV communities across a variety of environments in the Western Pacific that vary in their extent, biological composition, forcing physical factors and location. High spatial resolution satellite imagery (Quickbird, Ikonos and Worldview2) were acquired coincident with field surveys on each reef to collect georeferenced benthic photo transects, over various areas in the Western Pacific. Base line maps were created, from Roviana Lagoon Solomon island (600 km2), Bikini Atoll Marshall Island (800 Km2), Lizard Island, Australia (30 km2) and time series maps for geomorphic and benthic communities were collected for Heron Reef, Australia (24 km2) and Eastern Banks area of Moreton Bay, Australia (200 km2). The satellite image data were corrected for radiometric and atmospheric distortions to at-surface reflectance. Georeferenced benthic photos were acquired by divers or Autonomous Underwater Vehicles, analysed for benthic cover composition, and used for calibration and validation purposes. Hierarchical mapping from: reef/non-reef (1000's - 10000's m); reef type (100's - 1000's m); 'geomorphic zone' (10's - 100's m); to
Wang, Jun; Xu, Xiaoguang; Ding, Shouguo; Zeng, Jing; Spurr, Robert; Liu, Xiong; Chance, Kelly; Mishchenko, Michael I.
We present a numerical testbed for remote sensing of aerosols, together with a demonstration for evaluating retrieval synergy from a geostationary satellite constellation. The testbed combines inverse (optimal-estimation) software with a forward model containing linearized code for computing particle scattering (for both spherical and non-spherical particles), a kernel-based (land and ocean) surface bi-directional reflectance facility, and a linearized radiative transfer model for polarized radiance. Calculation of gas absorption spectra uses the HITRAN (HIgh-resolution TRANsmission molecular absorption) database of spectroscopic line parameters and other trace species cross-sections. The outputs of the testbed include not only the Stokes 4-vector elements and their sensitivities (Jacobians) with respect to the aerosol single scattering and physical parameters (such as size and shape parameters, refractive index, and plume height), but also DFS (Degree of Freedom for Signal) values for retrieval of these parameters. This testbed can be used as a tool to provide an objective assessment of aerosol information content that can be retrieved for any constellation of (planned or real) satellite sensors and for any combination of algorithm design factors (in terms of wavelengths, viewing angles, radiance and/or polarization to be measured or used). We summarize the components of the testbed, including the derivation and validation of analytical formulae for Jacobian calculations. Benchmark calculations from the forward model are documented. In the context of NASA's Decadal Survey Mission GEOCAPE (GEOstationary Coastal and Air Pollution Events), we demonstrate the use of the testbed to conduct a feasibility study of using polarization measurements in and around the O2 A band for the retrieval of aerosol height information from space, as well as an to assess potential improvement in the retrieval of aerosol fine and coarse mode aerosol optical depth (AOD) through the
Wright, Daniel B.; Mantilla, Ricardo; Peters-Lidard, Christa D.
RainyDay is a Python-based platform that couples rainfall remote sensing data with Stochastic Storm Transposition (SST) for modeling rainfall-driven hazards such as floods and landslides. SST effectively lengthens the extreme rainfall record through temporal resampling and spatial transposition of observed storms from the surrounding region to create many extreme rainfall scenarios. Intensity-Duration-Frequency (IDF) curves are often used for hazard modeling but require long records to describe the distribution of rainfall depth and duration and do not provide information regarding rainfall space-time structure, limiting their usefulness to small scales. In contrast, RainyDay can be used for many hazard applications with 1-2 decades of data, and output rainfall scenarios incorporate detailed space-time structure from remote sensing. Thanks to global satellite coverage, RainyDay can be used in inaccessible areas and developing countries lacking ground measurements, though results are impacted by remote sensing errors. RainyDay can be useful for hazard modeling under nonstationary conditions. PMID:29657544
Streett, D.; Warren, C.
During the Deepwater Horizon spill, NOAA imagery analysts in the Satellite Analysis Branch (SAB) issued more than 300 near-real-time satellite-based oil spill analyses. These analyses were used by the oil spill response community for planning, issuing surface oil trajectories and tasking assets (e.g., oil containment booms, skimmers, overflights). SAB analysts used both Synthetic Aperture Radar (SAR) and high resolution visible/near IR multispectral satellite imagery as well as a variety of ancillary datasets. Satellite imagery used included ENVISAT ASAR (ESA), TerraSAR-X (DLR), Cosmo-Skymed (ASI), ALOS (JAXA), Radarsat (MDA), ENVISAT MERIS (ESA), SPOT (SPOT Image Corp.), Aster (NASA), MODIS (NASA), and AVHRR (NOAA). Ancillary datasets included ocean current information, wind information, location of natural oil seeps and a variety of in situ oil observations. The analyses were available as jpegs, pdfs, shapefiles and through Google, KML files and also available on a variety of websites including Geoplatform and ERMA. From the very first analysis issued just 5 hours after the rig sank through the final analysis issued in August, the complete archive is still publicly available on the NOAA/NESDIS website http://www.ssd.noaa.gov/PS/MPS/deepwater.html SAB personnel also served as the Deepwater Horizon International Disaster Charter Project Manager (at the official request of the USGS). The Project Manager’s primary responsibility was to acquire and oversee the processing and dissemination of satellite data generously donated by numerous private companies and nations in support of the oil spill response including some of the imagery described above. SAB has begun to address a number of goals that will improve our routine oil spill response as well as help assure that we are ready for the next spill of national significance. We hope to (1) secure a steady, abundant and timely stream of suitable satellite imagery even in the absence of large-scale emergencies such as
Allen, G. H.; David, C. H.; Andreadis, K. M.; Emery, C. M.; Famiglietti, J. S.
Earth observing satellites provide valuable near real-time (NRT) information about flood occurrence and magnitude worldwide. This NRT information can be used in early flood warning systems and other flood management applications to save lives and mitigate flood damage. However, these NRT products are only useful to early flood warning systems if they are quickly made available, with sufficient time for flood mitigation actions to be implemented. More specifically, NRT data latency, or the time period between the satellite observation and when the user has access to the information, must be less than the time it takes a flood to travel from the flood observation location to a given downstream point of interest. Yet the paradigm that "lower latency is always better" may not necessarily hold true in river systems due to tradeoffs between data latency and data quality. Further, the existence of statistical breaks in the global distribution of flood wave travel time (i.e. a jagged statistical distribution) would represent preferable latencies for river-observation NRT remote sensing products. Here we present a global analysis of flood wave velocity (i.e. flow celerity) and travel time. We apply a simple kinematic wave model to a global hydrography dataset and calculate flow wave celerity and travel time during bankfull flow conditions. Bankfull flow corresponds to the condition of maximum celerity and thus we present the "worst-case scenario" minimum flow wave travel time. We conduct a similar analysis with respect to the time it takes flood waves to reach the next downstream city, as well as the next downstream reservoir. Finally, we conduct these same analyses, but with regards to the technical capabilities of the planned Surface Water and Ocean Topography (SWOT) satellite mission, which is anticipated to provide waterbody elevation and extent measurements at an unprecedented spatial and temporal resolution. We validate these results with discharge records from paired
Miles, S.; Gillie, M.
Task 18 working group of the International Energy Agency's Hydrogen Implementing Agreement has been evaluating and documenting experiences with renewable based hydrogen energy projects in remote and island communities in the United Kingdom, Canada, Norway, Iceland, Gran Canaria, Spain and New Zealand. The objective was to examine the lessons learned from existing projects and provide recommendations regarding the effective development of hydrogen systems. In order to accomplish this task, some of the drivers behind the niche markets where hydrogen systems have already been developed, or are in the development stages, were studied in order to determine how these could be expanded and modified to reach new markets. Renewable based hydrogen energy projects for remote and island communities are currently a key niche market. This paper compared various aspects of these projects and discussed the benefits, objectives and barriers facing the development of a hydrogen-based economy
Zoran, M. A.; Nicolae, D. N.; Talianu, C. L.; Ciobanu, M.; Ciuciu, J. G.
The synergistic use of multi-temporal and multi-spectral remote sensing data offers the possibility of monitoring of environment quality in the vicinity of nuclear power plants (NPP). Advanced digital processing techniques applied to several LANDSAT, MODIS and ASTER data are used to assess the extent and magnitude of radiation and non-radiation effects on the water, near field soil, vegetation and air for NPP Cernavoda , Romania . Cernavoda Unit 1 power plant, using CANDU technology, having 706.5 MW power, is successfully in operation since 1996. Cernavoda Unit 2 which is currently under construction will be operational in 2007. Thermal discharge from nuclear reactor cooling is dissipated as waste heat in Danube-Black -Sea Canal and Danube river. Water temperature distributions captured in thermal IR imagery are correlated with meteorological parameters. Additional information regarding flooding events and earthquake risks is considered . During the winter, the thermal plume is localized to an area within a few km of the power plant, and the temperature difference between the plume and non-plume areas is about 1.5 oC. During the summer and fall, there is a larger thermal plume extending 5-6 km far along Danube Black Sea Canal, and the temperature change is about 1.0 oC. Variation of surface water temperature in the thermal plume is analyzed. The strong seasonal difference in the thermal plume is related to vertical mixing of the water column in winter and to stratification in summer. Hydrodynamic simulation leads to better understanding of the mechanisms by which waste heat from NPP Cernavoda is dissipated in the environment.
XCOR Aerospace, a commercial space company, is planning to provide frequent, low cost access to near-Earth space on the Lynx suborbital Reusable Launch Vehicle (sRLV). Measurements in the external vacuum environment can be made and can launch from most runways on a limited lead time. Lynx can operate as a platform to perform suborbital in situ measurements and remote sensing to supplement models and simulations with new data points. These measurements can serve as a quantitative link to existing instruments and be used as a basis to calibrate detectors on spacecraft. Easier access to suborbital data can improve the longevity and cohesiveness of spacecraft and ground-based resources. A study of how these measurements can be made on Lynx sRLV will be presented. At the boundary between terrestrial and space weather, measurements from instruments on Lynx can help develop algorithms to optimize the consolidation of ground and satellite based data as well as assimilate global models with new data points. For example, current tides and the equatorial electrojet, essential to understanding the Thermosphere-Ionosphere system, can be measured in situ frequently and on short notice. Furthermore, a negative-ion spectrometer and a Faraday cup, can take measurements of the D-region ion composition. A differential GPS receiver can infer the spatial gradient of ionospheric electron density. Instruments and optics on spacecraft degrade over time, leading to calibration drift. Lynx can be a cost effective platform for deploying a reference instrument to calibrate satellites with a frequent and fast turnaround and a successful return of the instrument. A calibrated reference instrument on Lynx can make collocated observations as another instrument and corrections are made for the latter, thus ensuring data consistency and mission longevity. Aboard a sRLV, atmospheric conditions that distort remotely sensed data (ground and spacecraft based) can be measured in situ. Moreover, an
Zhao, Y.; Lobell, D. B.; Chen, X.
A large gap between maize yields on average farmers' fields and the highest yields achieved by either experiment or farmers is typical throughout the developing world, including in the North China Plain (NCP). This maize yield gap as identified by previous studies indicates large opportunities for raising yield by improving agronomy. Quzhou county is typical of the winter-wheat summer-maize system in NCP where the average plot size is as small as 0.25 hectares. To analyze this cropping system amidst the challenge of substantial heterogeneity, we identified fields that were either persistently higher or lower yielding according to the remote sensing yield estimates, and then conducted detailed field surveys. We found irrigation facility to be a major constraint to yield both in terms of irrigation water quality and farmers' access to wells. In total, improving the access to unsalty water would be associated with a 0.32t/ha (4.2%) increase in multi-year average yield. In addition, farmers' method of choosing cultivar, which likely relates to their overall knowledge level, significantly explained yield variation. In particular, those choosing cultivars according to technician advice, personal experiences and high yielding neighbors' advice had on average higher yield than farmers that either followed seed sellers' advice or collectively purchased seeds. Overall, the study presents a generalizable methodology of assessing yield gap as well as its persistent factors using a combination of satellite and survey data.
Belleman, J; González, J L
New electronics has been developed for the remote control of the pick-up electrodes at the CERN Proton Synchrotron (PS). Communication between VME-based control computers and remote equipment is via full duplex point-to-point digital data links. Data are sent and received in serial format over simple twisted pairs at a rate of 1 Mbit/s, for distances of up to 300 m. Coupling transformers are used to avoid ground loops. The link hardware consists of a general-purpose VME-module, the 'TRX' (transceiver), containing four FIFO-buffered communication channels, and a dedicated control card for each remote station. Remote transceiver electronics is simple enough not to require micro-controllers or processors. Currently, some sixty pick-up stations of various types, all over the PS Complex (accelerators and associated beam transfer lines) are equipped with the new system. Even though the TRX was designed primarily for communication with pick-up electronics, it could also be used for other purposes, for example to for...
Schneider, Philipp; Stebel, Kerstin; Ajtai, Nicolae; Diamandi, Andrei; Horalek, Jan; Nicolae, Doina; Stachlewska, Iwona; Zehner, Claus
Here, we present a new ESA-funded project entitled Satellite based Monitoring Initiative for Regional Air quality (SAMIRA), which aims at improving regional and local air quality monitoring through synergetic use of data from present and upcoming satellites, traditionally used in situ air quality monitoring networks and output from chemical transport models. Through collaborative efforts in four countries, namely Romania, Poland, the Czech Republic and Norway, all with existing air quality problems, SAMIRA intends to support the involved institutions and associated users in their national monitoring and reporting mandates as well as to generate novel research in this area. Despite considerable improvements in the past decades, Europe is still far from achieving levels of air quality that do not pose unacceptable hazards to humans and the environment. Main concerns in Europe are exceedances of particulate matter (PM), ground-level ozone, benzo(a)pyrene (BaP) and nitrogen dioxide (NO2). While overall sulfur dioxide (SO2) emissions have decreased in recent years, regional concentrations can still be high in some areas. The objectives of SAMIRA are to improve algorithms for the retrieval of hourly aerosol optical depth (AOD) maps from SEVIRI, and to develop robust methods for deriving column- and near-surface PM maps for the study area by combining satellite AOD with information from regional models. The benefit to existing monitoring networks (in situ, models, satellite) by combining these datasets using data fusion methods will be tested for satellite-based NO2, SO2, and PM/AOD. Furthermore, SAMIRA will test and apply techniques for downscaling air quality-related EO products to a spatial resolution that is more in line with what is generally required for studying urban and regional scale air quality. This will be demonstrated for a set of study sites that include the capitals of the four countries and the highly polluted areas along the border of Poland and the
K. H. Lee
Full Text Available In East Asia, satellite observation is important because aerosols from natural and anthropogenic sources have been recognized as a major source of regional and global air pollution. However, retrieving aerosols properties from satellite observations over land can be difficult because of the surface reflection, complex aerosol composition, and aerosol absorption. In this study, a new aerosol retrieval method called as the Moderate Resolution Imaging Spectroradiometer (MODIS satellite aerosol retrieval (MSTAR was developed and applied to three different aerosol event cases over East Asia. MSTAR uses a separation technique that can distinguish aerosol reflectance from top-of-atmosphere (TOA reflectance. The aerosol optical thickness (AOT was determined by comparing this aerosol reflectance with pre-calculated values. Three case studies show how the methodology identifies discrepancies between measured and calculated values to retrieve more accurate AOT. The comparison between MODIS and the Aerosol Robotic Network (AERONET showed improvement using the suggested methodology with the cluster-based look-up-tables (LUTs (linear slope = 0.94, R = 0.92 than using operational MODIS collection 5 aerosol products (linear slope = 0.78, R = 0.87. In conclusion, the suggested methodology is shown to work well with aerosol models acquired by statistical clustering of the observation data in East Asia.
Böer, M; Thien, W; Tölke, D
In the course of a thesis submitted for a diploma degree within the Fachhochschule Oldenburg the Serengeti Safaripark was surveyed in autumn and winter 1996/97 laying in the planning foundations for the application for licences from the controlling authorities. Taking into consideration the special way of keeping animals in the Serengeti Safaripark (game ranching, spacious walk-through-facilities) the intention was to employ the outstanding satellite based geodesy. This technology relies on special aerials receiving signals from 24 satellites which circle around the globe. These data are being gathered and examined. This examination produces the exact position of this aerial in a system of coordinates which allows depicting this point on a map. This procedure was used stationary (from a strictly defined point) as well as in the movement (in a moving car). Additionally conventional procedures were used when the satellite based geodesy came to its limits. Finally a detailed map of the Serengeti Safaripark was created which shows the position and size of stables and enclosures as well as wood and water areas and the sectors of the leisure park. Furthermore the established areas of the enclosures together with an already existing animal databank have flown into an information system with the help of which the stock of animals can be managed enclosure-orientated.
Full Text Available Image registration is an important task in many computer vision applications such as fusion systems, 3D shape recovery and earth observation. Particularly, registering satellite images is challenging and time-consuming due to limited resources and large image size. In such scenario, state-of-the-art image registration methods such as scale-invariant feature transform (SIFT may not be suitable due to high processing time. In this paper, we propose an algorithm based on block processing via entropy to register satellite images. The performance of the proposed method is evaluated using different real images. The comparative analysis shows that it not only reduces the processing time but also enhances the accuracy.
Checchi, Francesco; Stewart, Barclay T; Palmer, Jennifer J; Grundy, Chris
Estimating the size of forcibly displaced populations is key to documenting their plight and allocating sufficient resources to their assistance, but is often not done, particularly during the acute phase of displacement, due to methodological challenges and inaccessibility. In this study, we explored the potential use of very high resolution satellite imagery to remotely estimate forcibly displaced populations. Our method consisted of multiplying (i) manual counts of assumed residential structures on a satellite image and (ii) estimates of the mean number of people per structure (structure occupancy) obtained from publicly available reports. We computed population estimates for 11 sites in Bangladesh, Chad, Democratic Republic of Congo, Ethiopia, Haiti, Kenya and Mozambique (six refugee camps, three internally displaced persons' camps and two urban neighbourhoods with a mixture of residents and displaced) ranging in population from 1,969 to 90,547, and compared these to "gold standard" reference population figures from census or other robust methods. Structure counts by independent analysts were reasonably consistent. Between one and 11 occupancy reports were available per site and most of these reported people per household rather than per structure. The imagery-based method had a precision relative to reference population figures of layout. For each site, estimates were produced in 2-5 working person-days. In settings with clearly distinguishable individual structures, the remote, imagery-based method had reasonable accuracy for the purposes of rapid estimation, was simple and quick to implement, and would likely perform better in more current application. However, it may have insurmountable limitations in settings featuring connected buildings or shelters, a complex pattern of roofs and multi-level buildings. Based on these results, we discuss possible ways forward for the method's development.
Full Text Available The SatBałtyk (Satellite Monitoring of the Baltic Sea Environment project is being realized in Poland by the SatBałtyk Scientific Consortium, specifically appointed for this purpose, which associates four scientific institutions: the Institute of Oceanology PAN in Sopot - coordinator of the project, the University of Gdańsk (Institute of Oceanography, the Pomeranian Academy in Słupsk (Institute of Physics and the University of Szczecin (Institute of Marine Sciences. The project is aiming to prepare a technical infrastructure and set in motion operational procedures for the satellite monitoring of the Baltic Sea ecosystem. The main sources of input data for this system will be the results of systematic observations by metrological and environmental satellites such as TIROS N/NOAA, MSG (currently Meteosat 10, EOS/AQUA and Sentinel -1, 2, 3 (in the future. The system will deliver on a routine basis the variety of structural and functional properties of this sea, based on data provided by relevant satellites and supported by hydro-biological models. Among them: the solar radiation influx to the sea’s waters in various spectral intervals, energy balances of the short- and long-wave radiation at the Baltic Sea surface and in the upper layers of the atmosphere over the Baltic, sea surface temperature distribution, dynamic states of the water surface, concentrations of chlorophyll a and other phytoplankton pigments in the Baltic waters, spatial distributions of algal blooms, the occurrence of coastal upwelling events, and the characteristics of primary production of organic matter and photosynthetically released oxygen in the water and many others. The structure of the system and preliminary results will be presented.
Liu, Z.; Shie, C. L.; Meyer, D. J.
Global satellite-based precipitation products have been widely used in research and applications around the world. Compared to ground-based observations, satellite-based measurements provide precipitation data on a global scale, especially in remote continents and over oceans. Over the years, satellite-based precipitation products have evolved from single sensor and single algorithm to multi-sensors and multi-algorithms. As a result, many satellite-based precipitation products have been enhanced such as spatial and temporal coverages. With inclusion of ground-based measurements, biases of satellite-based precipitation products have been significantly reduced. However, data quality issues still exist and can be caused by many factors such as observations, satellite platform anomaly, algorithms, production, calibration, validation, data services, etc. The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) is home to NASA global precipitation product archives including the Tropical Rainfall Measuring Mission (TRMM), the Global Precipitation Measurement (GPM), as well as other global and regional precipitation products. Precipitation is one of the top downloaded and accessed parameters in the GES DISC data archive. Meanwhile, users want to easily locate and obtain data quality information at regional and global scales to better understand how precipitation products perform and how reliable they are. As data service providers, it is necessary to provide an easy access to data quality information, however, such information normally is not available, and when it is available, it is not in one place and difficult to locate. In this presentation, we will present challenges and activities at the GES DISC to address precipitation data quality issues.
Tadesse, Tsegaye; Senay, Gabriel B.; Berhan, Getachew; Regassa, Teshome; Beyene, Shimelis
Satellite-derived evapotranspiration anomalies and normalized difference vegetation index (NDVI) products from Moderate Resolution Imaging Spectroradiometer (MODIS) data are currently used for African agricultural drought monitoring and food security status assessment. In this study, a process to evaluate satellite-derived evapotranspiration (ETa) products with a geospatial statistical exploratory technique that uses NDVI, satellite-derived rainfall estimate (RFE), and crop yield data has been developed. The main goal of this study was to evaluate the ETa using the NDVI and RFE, and identify a relationship between the ETa and Ethiopia's cereal crop (i.e., teff, sorghum, corn/maize, barley, and wheat) yields during the main rainy season. Since crop production is one of the main factors affecting food security, the evaluation of remote sensing-based seasonal ETa was done to identify the appropriateness of this tool as a proxy for monitoring vegetation condition in drought vulnerable and food insecure areas to support decision makers. The results of this study showed that the comparison between seasonal ETa and RFE produced strong correlation (R2 > 0.99) for all 41 crop growing zones in Ethiopia. The results of the spatial regression analyses of seasonal ETa and NDVI using Ordinary Least Squares and Geographically Weighted Regression showed relatively weak yearly spatial relationships (R2 products have a good predictive potential for these 31 identified zones in Ethiopia. Decision makers may potentially use ETa products for monitoring cereal crop yields and early warning of food insecurity during drought years for these identified zones.
Hsu, N. Christina; Gautam, Ritesh
The Himalayan glaciers and snowpacks play an important role in the hydrological cycle over Asia. The seasonal snow melt from the Himalayan glaciers and snowpacks is one of the key elements to the livelihood of the downstream densely populated regions of South Asia. During the pre-monsoon season (April-May-June), South Asia not only experiences the reversal of the regional meridional tropospheric temperature gradient (i.e., the onset of the summer monsoon), but also is being bombarded by dry westerly airmass that transports mineral dust from various Southwest Asian desert and arid regions into the Indo-Gangetic Plains in northern India. Mixed with heavy anthropogenic pollution, mineral dust constitutes the bulk of regional aerosol loading and forms an extensive and vertically extended brown haze lapping against the southern slopes of the Himalayas. Episodic dust plumes are advected over the Himalayas, and are discernible in satellite imagery, resulting in dust-capped snow surface. Motivated by the potential implications of accelerated snowmelt, we examine the changes in radiative energetics induced by aerosol transport over the Himalayan snow cover by utilizing space borne observations. Our objective lies in the investigation of potential impacts of aerosol solar absorption on the Top-of-Atmosphere (TOA) spectral reflectivity and the broadband albedo, and hence the accelerated snowmelt, particularly in the western Himalayas. Lambertian Equivalent Reflectivity (LER) in the visible and near-infrared wavelengths, derived from Moderate Resolution Imaging Spectroradiometer radiances, is used to generate statistics for determining perturbation caused due to dust layer over snow surface in over ten years of continuous observations. Case studies indicate significant reduction of LER ranging from 5 to 8% in the 412-860nm spectra. Broadband flux observations, from the Clouds and the Earth's Radiant Energy System, are also used to investigate changes in shortwave TOA flux over
Van Den Hoek, Jamon; Read, Jordan S.; Winslow, Luke A.; Montesano, Paul; Markfort, Corey D.
Satellite-based measurements of vegetation canopy structure have been in common use for the last decade but have never been used to estimate canopy's impact on wind sheltering of individual lakes. Wind sheltering is caused by slower winds in the wake of topography and shoreline obstacles (e.g. forest canopy) and influences heat loss and the flux of wind-driven mixing energy into lakes, which control lake temperatures and indirectly structure lake ecosystem processes, including carbon cycling and thermal habitat partitioning. Lakeshore wind sheltering has often been parameterized by lake surface area but such empirical relationships are only based on forested lakeshores and overlook the contributions of local land cover and terrain to wind sheltering. This study is the first to examine the utility of satellite imagery-derived broad-scale estimates of wind sheltering across a diversity of land covers. Using 30 m spatial resolution ASTER GDEM2 elevation data, the mean sheltering height, hs, being the combination of local topographic rise and canopy height above the lake surface, is calculated within 100 m-wide buffers surrounding 76,000 lakes in the U.S. state of Wisconsin. Uncertainty of GDEM2-derived hs was compared to SRTM-, high-resolution G-LiHT lidar-, and ICESat-derived estimates of hs, respective influences of land cover type and buffer width on hsare examined; and the effect of including satellite-based hs on the accuracy of a statewide lake hydrodynamic model was discussed. Though GDEM2 hs uncertainty was comparable to or better than other satellite-based measures of hs, its higher spatial resolution and broader spatial coverage allowed more lakes to be included in modeling efforts. GDEM2 was shown to offer superior utility for estimating hs compared to other satellite-derived data, but was limited by its consistent underestimation of hs, inability to detect within-buffer hs variability, and differing accuracy across land cover types. Nonetheless
Kahn, Ralph A.
The organizers of the National Academy of Sciences Arthur M. Sackler Colloquia Series on Improving Our Fundamental Understanding of the Role of Aerosol-Cloud Interactions in the Climate System would like to post Ralph Kahn's presentation entitled Remote Sensing of Aerosols from Satellites: Why has it been so difficult to quantify aerosol-cloud interactions for climate assessment, and how can we make progress? to their public website.
Ershadi, A.; Houborg, R.; McCabe, M. F.; Anderson, M. C.; Hain, C.
Satellite remote sensing has the potential to offer spatially and temporally distributed information on land surface characteristics, which may be used as inputs and constraints for estimating land surface fluxes of carbon, water and energy. Enhanced satellite-based monitoring systems for aiding local water resource assessments and agricultural management activities are particularly needed for the Middle East and North Africa (MENA) region. The MENA region is an area characterized by limited fresh water resources, an often inefficient use of these, and relatively poor in-situ monitoring as a result of sparse meteorological observations. To address these issues, an integrated modeling approach for near real-time monitoring of land surface states and fluxes at fine spatio-temporal scales over the MENA region is presented. This approach is based on synergistic application of multiple sensors and wavebands in the visible to shortwave infrared and thermal infrared (TIR) domain. The multi-scale flux mapping and monitoring system uses the Atmosphere-Land Exchange Inverse (ALEXI) model and associated flux disaggregation scheme (DisALEXI), and the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) in conjunction with model reanalysis data and multi-sensor remotely sensed data from polar orbiting (e.g. Landsat and MODerate resolution Imaging Spectroradiometer (MODIS)) and geostationary (MSG; Meteosat Second Generation) satellite platforms to facilitate time-continuous (i.e. daily) estimates of field-scale water, energy and carbon fluxes. Within this modeling system, TIR satellite data provide information about the sub-surface moisture status and plant stress, obviating the need for precipitation input and a detailed soil surface characterization (i.e. for prognostic modeling of soil transport processes). The STARFM fusion methodology blends aspects of high frequency (spatially coarse) and spatially fine resolution sensors and is applied directly to flux output
the four primary technology areas for 2016 was “energy storage technology for mobile electric micro-grid applications” . 4 Figure 1.3. Typical...providing electrical power to a remote U.S. contingency base. The first program minimizes the total cost of electricity production and the second program...battlefield and at home are a high priority for the U.S. military. We present twomixed integer linear programs developed for amicrogrid providing electrical
Full Text Available An accurate and comprehensive representation of an observation task is a prerequisite in disaster monitoring to achieve reliable sensor observation planning. However, the extant disaster event or task information models do not fully satisfy the observation requirements for the accurate and efficient planning of remote-sensing satellite sensors. By considering the modeling requirements for a disaster observation task, we propose an observation task chain (OTChain representation model that includes four basic OTChain segments and eight-tuple observation task metadata description structures. A prototype system, namely OTChainManager, is implemented to provide functions for modeling, managing, querying, and visualizing observation tasks. In the case of flood water monitoring, we use a flood remote-sensing satellite sensor observation task for the experiment. The results show that the proposed OTChain representation model can be used in modeling process-owned flood disaster observation tasks. By querying and visualizing the flood observation task instances in the Jinsha River Basin, the proposed model can effectively express observation task processes, represent personalized observation constraints, and plan global remote-sensing satellite sensor observations. Compared with typical observation task information models or engines, the proposed OTChain representation model satisfies the information demands of the OTChain and its processes as well as impels the development of a long time-series sensor observation scheme.
Brunner, J.; Pierce, R. B.; Lenzen, A.
A satellite based surface visibility retrieval has been developed using Moderate Resolution Imaging Spectroradiometer (MODIS) measurements as a proxy for Advanced Baseline Imager (ABI) data from the next generation of Geostationary Operational Environmental Satellites (GOES-R). The retrieval uses a multiple linear regression approach to relate satellite aerosol optical depth, fog/low cloud probability and thickness retrievals, and meteorological variables from numerical weather prediction forecasts to National Weather Service Automated Surface Observing System (ASOS) surface visibility measurements. Validation using independent ASOS measurements shows that the GOES-R ABI surface visibility retrieval (V) has an overall success rate of 64.5% for classifying Clear (V ≥ 30 km), Moderate (10 km ≤ V United States Environmental Protection Agency (EPA) and National Park Service (NPS) Interagency Monitoring of Protected Visual Environments (IMPROVE) network, and provide useful information to the regional planning offices responsible for developing mitigation strategies required under the EPA's Regional Haze Rule, particularly during regional haze events associated with smoke from wildfires.
Leptoukh, Gregory; Lynnes, C.; Ahmad, S.; Fox, P.; Zednik, S.; West, P.
With the recent attention to climate change and proliferation of remote-sensing data utilization, climate model and various environmental monitoring and protection applications have begun to increasingly rely on satellite measurements. Research application users seek good quality satellite data, with uncertainties and biases provided for each data point. However, different communities address remote sensing quality issues rather inconsistently and differently. We describe our attempt to systematically characterize, capture, and provision quality and uncertainty information as it applies to the NASA MODIS Aerosol Optical Depth data product. In particular, we note the semantic differences in quality/bias/uncertainty at the pixel, granule, product, and record levels. We outline various factors contributing to uncertainty or error budget; errors. Web-based science analysis and processing tools allow users to access, analyze, and generate visualizations of data while alleviating users from having directly managing complex data processing operations. These tools provide value by streamlining the data analysis process, but usually shield users from details of the data processing steps, algorithm assumptions, caveats, etc. Correct interpretation of the final analysis requires user understanding of how data has been generated and processed and what potential biases, anomalies, or errors may have been introduced. By providing services that leverage data lineage provenance and domain-expertise, expert systems can be built to aid the user in understanding data sources, processing, and the suitability for use of products generated by the tools. We describe our experiences developing a semantic, provenance-aware, expert-knowledge advisory system applied to NASA Giovanni web-based Earth science data analysis tool as part of the ESTO AIST-funded Multi-sensor Data Synergy Advisor project.
Heras, E. de las; Lastra, D.; Vega, J.; Castro, R.; Ruiz, M.; Barrera, E.
Remote experimentation (RE) methods will be essential in next generation fusion devices. Requirements for long pulse RE will be: on-line data visualization, on-line data acquisition processes monitoring and on-line data acquisition systems interactions (start, stop or set-up modifications). Note that these methods are not oriented to real-time control of fusion plant devices. INDRA Sistemas S.A., CIEMAT (Centro de Investigaciones Energeticas Medioambientales y Tecnologicas) and UPM (Universidad Politecnica de Madrid) have designed a specific software architecture for these purposes. The architecture can be supported on the BeansNet platform, whose integration with an application server provides an adequate solution to the requirements. BeansNet is a JINI based framework developed by INDRA, which makes easy the implementation of a remote experimentation model based on a Service Oriented Architecture. The new software architecture has been designed on the basis of the experience acquired in the development of an upgrade of the TJ-II remote experimentation system.
Full Text Available With the increasing demand for high-resolution remote sensing images for mapping and monitoring the Earth’s environment, geometric positioning accuracy improvement plays a significant role in the image preprocessing step. Based on the statistical learning theory, we propose a new method to improve the geometric positioning accuracy without ground control points (GCPs. Multi-temporal images from the ZY-3 satellite are tested and the bias-compensated rational function model (RFM is applied as the block adjustment model in our experiment. An easy and stable weight strategy and the fast iterative shrinkage-thresholding (FIST algorithm which is widely used in the field of compressive sensing are improved and utilized to define the normal equation matrix and solve it. Then, the residual errors after traditional block adjustment are acquired and tested with the newly proposed inherent error compensation model based on statistical learning theory. The final results indicate that the geometric positioning accuracy of ZY-3 satellite imagery can be improved greatly with our proposed method.
Carozza, Ludovico; Bevilacqua, Alessandro
Improvements in communication and processing technologies have opened the doors to exploit on-board cameras to compute objects' spatial attitude using only the visual information from sequences of remote sensed images. The strategies and the algorithmic approach used to extract such information affect the estimation accuracy of the three-axis orientation of the object. This work presents a method for analyzing the most relevant error sources, including numerical ones, possible drift effects and their influence on the overall accuracy, referring to vision-based approaches. The method in particular focuses on the analysis of the image registration algorithm, carried out through on-purpose simulations. The overall accuracy has been assessed on a challenging case study, for which accuracy represents the fundamental requirement. In particular, attitude determination has been analyzed for small satellites, by comparing theoretical findings to metric results from simulations on realistic ground-truth data. Significant laboratory experiments, using a numerical control unit, have further confirmed the outcome. We believe that our analysis approach, as well as our findings in terms of error characterization, can be useful at proof-of-concept design and planning levels, since they emphasize the main sources of error for visual based approaches employed for satellite attitude estimation. Nevertheless, the approach we present is also of general interest for all the affine applicative domains which require an accurate estimation of three-dimensional orientation parameters (i.e., robotics, airborne stabilization).
De Las Heras, E.; Lastra, D. [INDRA Sistemas, S.A., Unidad de Sistemas de Control, Madrid (Spain); Vega, J.; Castro, R. [Association Euratom CIEMAT for Fusion, Madrid (Spain); Ruiz, M.; Barrera, E. [Universidad Politecnica de Madrid (Spain)
INDRA is the first Information Technology company in Spain and it presents here, through a series of transparencies, its own approach for the remote experimentation architecture for long pulses (REAL). All the architecture is based on Java-2 platform standards and REAL is a totally open architecture. By itself REAL offers significant advantages: -) access authentication and authorization under multiple security implementations, -) local or remote network access: LAN, WAN, VPN..., -) on-line access to acquisition systems for monitoring and configuration, -) scalability, flexibility, robustness, platform independence,.... The BeansNet implementation of REAL gives additional good things such as: -) easy implementation, -) graphical tool for service composition and configuration, -) availability and hot-swap (no need of stopping or restarting services after update or remodeling, and -) INDRA support. The implementation of BeansNet at the TJ-2 stellarator at Ciemat is presented. This document is made of the presentation transparencies. (A.C.)
Full Text Available Timely and accurate change detection of buildings provides important information for urban planning and management.Accompanying with the rapid development of satellite remote sensing technology,detecting building changes from high-resolution remote sensing images have received wide attention.Given that pixel-based methods of change detection often lead to low accuracy while object-based methods are complicated for uses,this research proposes a method that combines pixel-based and object-based methods for detecting building changes from high-resolution remote sensing images.First,based on the multiple features extracted from the high-resolution images,a random forest classifier is applied to detect changed building at the pixel level.Then,a segmentation method is applied to segement the post-phase remote sensing image and to get post-phase image objects.Finally,both changed building at the pixel level and post-phase image objects are fused to recognize the changed building objects.Multi-temporal QuickBird images are used as experiment data for building change detection with high-resolution remote sensing images,the results indicate that the proposed method could reduce the influence of environmental difference,such as light intensity and view angle,on building change detection,and effectively improve the accuracies of building change detection.
Gossart, A.; Souverijns, N.; Lhermitte, S.; Lenaerts, J.; Gorodetskaya, I.; Schween, J. H.; Van Lipzig, N. P. M.
Surface mass balance (SMB) strongly controls spatial and temporal variations in the Antarctic Ice Sheet (AIS) mass balance and its contribution to sea level rise. Currently, the scarcity of observational data and the challenges of climate modelling over the ice sheet limit our understanding of the processes controlling AIS SMB. Particularly, the impact of blowing snow on local SMB is not yet constrained and is subject to large uncertainties. To assess the impact of blowing snow on local SMB, we investigate the attenuated backscatter profiles from ceilometers at two East Antarctic locations in Dronning Maud Land. Ceilometers are robust ground-based remote sensing instruments that yield information on cloud base height and vertical structure, but also provide information on the particles present in the boundary layer. We developed a new algorithm to detect blowing snow (snow particles lifted by the wind from the surface to substantial height) from the ceilometer attenuated backscatter. The algorithm successfully allows to detect strong blowing snow signal from layers thicker than 15 m at the Princess Elisabeth (PE, (72°S, 23°E)) and Neumayer (70°S, 8° W) stations. Applying the algorithm to PE, we retrieve the frequency and annual cycle of blowing snow as well as discriminate between clear sky and overcast conditions during blowing snow. We further apply the blowing snow algorithm at PE to evaluate the blowing snow events detection by satellite imagery (Palm et al., 2011): the near-surface blowing snow layers are apparent in lidar backscatter profiles and enable snowdrift events detection (spatial and temporal frequency, height and optical depth). These data are processed from CALIPSO, at a high resolution (1x1 km digital elevation model). However, the remote sensing detection of blowing snow events by satellite is limited to layers of a minimal thickness of 20-30 m. In addition, thick clouds, mostly occurring during winter storms, can impede drifting snow
Wells, G. L.; Tapley, B. D.; Bettadpur, S. V.; Howard, T.; Porter, B.; Smith, S.; Teng, L.; Tapley, C.
The effective use of remote sensing products as guidance to emergency managers and first responders during field operations requires close coordination and communication with state-level decision makers, incident commanders and the leaders of individual strike teams. Information must be tailored to meet the needs of different emergency support functions and must contain current (ideally near real-time) data delivered in standard formats in time to influence decisions made under rapidly changing conditions. Since 2003, a representative of the University of Texas Center for Space Research (CSR) has served as a member of the Governor's Emergency Management Council and has directed the flow of information from remote sensing observations and high performance computing modeling and simulations to the Texas Division of Emergency Management in the State Operations Center. The CSR team has supported response and recovery missions resulting from hurricanes, tornadoes, flash floods, wildfires, oil spills and other natural and man-made disasters in Texas and surrounding states. Through web mapping services, state emergency managers and field teams have received threat model forecasts, real-time vehicle tracking displays and imagery to support search-and-clear operations before hurricane landfall, search-and-rescue missions following floods, tactical wildfire suppression, pollution monitoring and hazardous materials detection. Data servers provide near real-time satellite imagery collected by CSR's direct broadcast receiving system and post data products delivered during activations of the United Nations International Charter on Space and Major Disasters. In the aftermath of large-scale events, CSR is charged with tasking state aviation resources, including the Air National Guard and Texas Civil Air Patrol, to acquire geolocated aerial photography of the affected region for wide area damage assessment. A data archive for each disaster is available online for years following
Akanda, A. S.; Serman, E. A.; Jutla, A.
focuses on stretching this understanding to water and health implications in this growing megacity and adjoining slum areas, and how satellite remote sensing data products and derived knowledge can inform urban planning, water management, and public health sectors to adapt to these climatic and anthropogenic changes for the benefit of societies.
Lee, Zhongping; Shang, Shaoling; Hu, Chuanmin; Zibordi, Giuseppe
Using 901 remote-sensing reflectance spectra (R(rs)(λ), sr⁻¹, λ from 400 to 700 nm with a 5 nm resolution), we evaluated the correlations of R(rs)(λ) between neighboring spectral bands in order to characterize (1) the spectral interdependence of R(rs)(λ) at different bands and (2) to what extent hyperspectral R(rs)(λ) can be reconstructed from multiband measurements. The 901 R(rs) spectra were measured over a wide variety of aquatic environments in which water color varied from oceanic blue to coastal green or brown, with chlorophyll-a concentrations ranging from ~0.02 to >100 mg m⁻³, bottom depths from ~1 m to >1000 m, and bottom substrates including sand, coral reef, and seagrass. The correlation coefficient of R(rs)(λ) between neighboring bands at center wavelengths λ(k) and λ(l), r(Δλ)(λ(k), λ(l)), was evaluated systematically, with the spectral gap (Δλ=λ(l)-λ(k)) changing between 5, 10, 15, 20, 25, and 30 nm, respectively. It was found that r(Δλ) decreased with increasing Δλ, but remained >0.97 for Δλ≤20 nm for all spectral bands. Further, using 15 spectral bands between 400 and 710 nm, we reconstructed, via multivariant linear regression, hyperspectral R(rs)(λ) (from 400 to 700 nm with a 5 nm resolution). The percentage difference between measured and reconstructed R(rs) for each band in the 400-700 nm range was generally less than 1%, with a correlation coefficient close to 1.0. The mean absolute error between measured and reconstructed R(rs) was about 0.00002 sr⁻¹ for each band, which is significantly smaller than the R(rs) uncertainties from all past and current ocean color satellite radiometric products. These results echo findings of earlier studies that R(rs) measurements at ~15 spectral bands in the visible domain can provide nearly identical spectral information as with hyperspectral (contiguous bands at 5 nm spectral resolution) measurements. Such results provide insights for data
Schüttler, Tobias; Maman, Shimrit; Girwidz, Raimund
Context- and project-based teaching has proven to foster different affective and cognitive aspects of learning. As a versatile and multidisciplinary scientific research area with diverse applications for everyday life, satellite remote sensing is an interesting context for physics education. In this paper we give a brief overview of satellite remote sensing of vegetation and how to obtain your own, individual infrared remote sensing data with affordable converted digital cameras. This novel technique provides the opportunity to conduct individual remote sensing measurement projects with students in their respective environment. The data can be compared to real satellite data and is of sufficient accuracy for educational purposes.
Tilley, D.G.; Sarma, Y.V.B.
of several SAR systems are compared based upon image data in sheltered bays and reservoirs. The upper limits of SAR system resolution in high sea states are discussed relative to wind and wave measurements made near hurricane Josephine with NASA shuttle...
Coskun, H Gonca; Alganci, Ugur; Usta, Gokce
Accurate and timely information about land use and land cover (LULC) and its changes in urban areas are crucial for urban land management decision-making, ecosystem monitoring and urban planning. Also, monitoring and representation of urban sprawl and its effects on the LULC patterns and hydrological processes of an urbanized watershed is an essential part of water resource planning and management. This paper presents an image analysis study using multi temporal digital satellite imagery of LULC and changes in the Kucukcekmece Watershed (Metropolitan Istanbul, Turkey) from 1992 to 2006. The Kucukcekmece Basin includes portions of the Kucukcekmece District within the municipality of Istanbul so it faces a dramatic urbanization. An urban monitoring analysis approach was first used to implement a land cover classification. A change detection method controlled with ground truth information was then used to determine changes in land cover. During the study period, the variability and magnitude of hydrological components based on land-use patterns were cumulatively influenced by urban sprawl in the watershed. The proposed approach, which uses a combination of Remote Sensing (RS) and Geographical Information System (GIS) techniques, is an effective tool that enhances land-use monitoring, planning, and management of urbanized watersheds.
We estimated surface salinity flux and solar penetration from satellite data, and performed model simulations to examine the impact of including the satellite estimates on temperature, salinity, and dissolved oxygen distributions on the Louisiana continental shelf (LCS) near the ...
Zhang Yining; Ye Mei; Zhao Shujun
It designed a remote monitoring system of BESⅢ experiment based on web. The software of the system is mainly based on module programming. The Ajax technology and the MVC pattern is used in system framework construction. The function of selecting multiple tables is realized by structural checkbox tree using jstree library. Data chart is plotted by High Charts library. The updating of data curve is realized by the method of calculating the time span between the real data record to measure the http request. The system design can be used by detector monitoring system like BESⅢ. (authors)
Cappelle, J.; Iverson, S.A.; Takekawa, John Y.; Newman, S.H.; Dodman, T.; Gaidet, N.
We provide recommendations for implementing telemetry studies on waterfowl on the basis of our experience in a tracking study conducted in three countries of sub-Saharan Africa. The aim of the study was to document movements by duck species identified as priority candidates for the potential spread of avian influenza. Our study design included both captive and field test components on four wild duck species (Garganey, Comb Duck, White-faced Duck and Fulvous Duck). We used our location data to evaluate marking success and determine when signal loss occurred. The captive study of eight ducks marked with non-working transmitters in a zoo in Montpellier, France, prior to fieldwork showed no evidence of adverse effects, and the harness design appeared to work well. The field study in Malawi, Nigeria and Mali started in 2007 on 2 February, 6 February and 14 February, and ended on 22 November 2007 (288 d), 20 January 2010 (1 079 d), and 3 November 2008 (628 d), respectively. The field study indicated that 38 of 47 (81%) of the platform transmitter terminals (PTTs) kept transmitting after initial deployment, and the transmitters provided 15 576 locations. Signal loss during the field study was attributed to three main causes: PTT loss, PTT failure and mortality (natural, human-caused and PTT-related). The PTT signal quality varied by geographic region, and interference caused signal loss in the Mediterranean Sea region. We recommend careful attention at the beginning of the study to determine the optimum timing of transmitter deployment and the number of transmitters to be deployed per species. These sample sizes should be calculated by taking into account region-specific causes of signal loss to ensure research objectives are met. These recommendations should be useful for researchers undertaking a satellite tracking program, especially when working in remote areas of Africa where logistics are difficult or with poorly-known species. ?? NISC (Pty) Ltd.
Evlyn Márcia Leão de Moraes Novo
Full Text Available This work proposes a trophic state index based on the remote sensing retrieval of chlorophyll-α concentration. For that, in situ Bidirectional Reflectance Factor (BRF data acquired in the Ibitinga reservoir were resampled to match Landsat/TM spectral simulated bands (TM_sim bands and used to run linear correlation with concurrent measurements of chlorophyll-α concentration. Monte Carlo simulation was then applied to select the most suitable model relating chlorophyll-α concentration and simulated TM/Landsat reflectance. TM4_sim/TM3_sim ratio provided the best model with a R2 value of 0.78. The model was then inverted to create a look-up-table (LUT relating TM4_sim/TM3_sim ratio intervals to chlorophyll-α concentration trophic state classes covering the entire range measured in the reservoir. Atmospheric corrected Landsat TM images converted to surface reflectance were then used to generate a TM4/TM3 ratio image. The ratio image frequency distribution encompassed the range of TM4_sim/TM3_sim ratio indicating agreement between in situ and satellite data and supporting the use of satellite data to map chlorophyll- concentration trophic state distribution in the reservoir. Based on that, the LUT was applied to a Landsat/TM ratio image to map the spatial distribution of chlorophyll- trophic state classes in Ibitinga reservoir. Despite the stochastic selection of TM4_sim/TM3_sim ratio as the best input variable for modeling the chlorophyll-α concentration, it has a physical basis: high concentration of phytoplankton increases the reflectance in the near-infrared (TM4 and decreases the reflectance in the red (TM3. The band ratio, therefore, enhances the relationship between chlorophyll- concentration and remotely sensed reflectance.
Full Text Available Remote sensing is a rapid and reliable method for estimating crop growth data from individual plant to crops in irrigated agriculture ecosystem. The LAI is one of the important biophysical parameter for determining vegetation health, biomass, photosynthesis and evapotranspiration (ET for the modelling of crop yield and water productivity. Ground measurement of this parameter is tedious and time-consuming due to heterogeneity across the landscape over time and space. This study deals with the development of remote-sensing based empirical relationships for the estimation of ground-based LAI (LAIG using NDVI, modelled with and without atmospheric correction models for three irrigated crops (corn, wheat and rice grown in irrigated farms within Coleambally Irrigation Area (CIA which is located in southern Murray Darling basin, NSW in Australia. Extensive ground truthing campaigns were carried out to measure crop growth and to collect field samples of LAI using LAI- 2000 Plant Canopy Analyser and reflectance using CROPSCAN Multi Spectral Radiometer at several farms within the CIA. A Set of 12 cloud free Landsat 5 TM satellite images for the period of 2010-11 were downloaded and regression analysis was carried out to analyse the co-relationships between satellite and ground measured reflectance and to check the reliability of data sets for the crops. Among all the developed regression relationships between LAI and NDVI, the atmospheric correction process has significantly improved the relationship between LAI and NDVI for Landsat 5 TM images. The regression analysis also shows strong correlations for corn and wheat but weak correlations for rice which is currently being investigated.
Xiao, J.; Frolking, S. E.; Milliman, T. E.; Schneider, A.; Friedl, M. A.
Human population is rapidly urbanizing. In much of the world, cities are prone to hotter weather than surrounding rural areas - so-called `urban heat islands' - and this effect can have mortal consequences during heat waves. During the daytime, when the surface energy balance is driven by incoming solar radiation, the magnitude of urban warming is strongly influenced by surface albedo and the capacity to evaporate water (i.e., there is a strong relationship between vegetated land fraction and the ratio of sensible to latent heat loss or Bowen ratio). At nighttime, urban cooling is often inhibited by the thermal inertia of the built environment and anthropogenic heat exhaust from building and transportation energy use. We evaluated a suite of global remote sensing data sets representing a range of urban characteristics against MODIS-derived land-surface temperature differences between urban and surrounding rural areas. We included two new urban datasets in this analysis - MODIS-derived change in global urban extent and global urban microwave backscatter - along with several MODIS standard products and DMSP/OLS nighttime lights time series data. The global analysis spanned a range of urban characteristics that likely influence the magnitude of daytime and/or nighttime urban heat islands - urban size, population density, building density, state of development, impervious fraction, eco-climatic setting. Specifically, we developed new satellite datasets and synthesizing these with existing satellite data into a global database of urban land surface parameters, used two MODIS land surface temperature products to generate time series of daytime and nighttime urban heat island effects for 30 large cities across the globe, and empirically analyzed these data to determine specifically which remote sensing-based characterizations of global urban areas have explanatory power with regard to both daytime and nighttime urban heat islands.
Thomas, Aparna; George, Minu
The two major areas of concern in industrial establishments are monitoring and security. The remote monitoring and controlling can be established with the help of Web technology. Managers can monitor and control the equipment in the remote area through a web browser. The targeted area includes all type of susceptible environment like gas filling station, research and development laboratories. The environmental parameters like temperature, light intensity, gas etc. can be monitored. Security is a very important factor in an industrial setup. So motion detection feature is added to the system to ensure the security. The remote monitoring and controlling system makes use of the latest, less power consumptive and fast working microcontroller like S3C2440. This system is based on ARM9 and Linux operating system. The ARM9 will collect the sensor data and establish real time video monitoring along with motion detection feature. These captured video data as well as environmental data is transmitted over internet using embedded web server which is integrated within the ARM9 board.
Bhatti, Haris Akram; Rientjes, Tom; Haile, Alemseged Tamiru; Habib, Emad; Verhoef, Wouter
With the advances in remote sensing technology, satellite-based rainfall estimates are gaining attraction in the field of hydrology, particularly in rainfall-runoff modeling. Since estimates are affected by errors correction is required. In this study, we tested the high resolution National Oceanic and Atmospheric Administration's (NOAA) Climate Prediction Centre (CPC) morphing technique (CMORPH) satellite rainfall product (CMORPH) in the Gilgel Abbey catchment, Ethiopia. CMORPH data at 8 km-30 min resolution is aggregated to daily to match in-situ observations for the period 2003-2010. Study objectives are to assess bias of the satellite estimates, to identify optimum window size for application of bias correction and to test effectiveness of bias correction. Bias correction factors are calculated for moving window (MW) sizes and for sequential windows (SW's) of 3, 5, 7, 9, …, 31 days with the aim to assess error distribution between the in-situ observations and CMORPH estimates. We tested forward, central and backward window (FW, CW and BW) schemes to assess the effect of time integration on accumulated rainfall. Accuracy of cumulative rainfall depth is assessed by Root Mean Squared Error (RMSE). To systematically correct all CMORPH estimates, station based bias factors are spatially interpolated to yield a bias factor map. Reliability of interpolation is assessed by cross validation. The uncorrected CMORPH rainfall images are multiplied by the interpolated bias map to result in bias corrected CMORPH estimates. Findings are evaluated by RMSE, correlation coefficient (r) and standard deviation (SD). Results showed existence of bias in the CMORPH rainfall. It is found that the 7 days SW approach performs best for bias correction of CMORPH rainfall. The outcome of this study showed the efficiency of our bias correction approach.
Haris Akram Bhatti
Full Text Available With the advances in remote sensing technology, satellite-based rainfall estimates are gaining attraction in the field of hydrology, particularly in rainfall-runoff modeling. Since estimates are affected by errors correction is required. In this study, we tested the high resolution National Oceanic and Atmospheric Administration’s (NOAA Climate Prediction Centre (CPC morphing technique (CMORPH satellite rainfall product (CMORPH in the Gilgel Abbey catchment, Ethiopia. CMORPH data at 8 km-30 min resolution is aggregated to daily to match in-situ observations for the period 2003–2010. Study objectives are to assess bias of the satellite estimates, to identify optimum window size for application of bias correction and to test effectiveness of bias correction. Bias correction factors are calculated for moving window (MW sizes and for sequential windows (SW’s of 3, 5, 7, 9, …, 31 days with the aim to assess error distribution between the in-situ observations and CMORPH estimates. We tested forward, central and backward window (FW, CW and BW schemes to assess the effect of time integration on accumulated rainfall. Accuracy of cumulative rainfall depth is assessed by Root Mean Squared Error (RMSE. To systematically correct all CMORPH estimates, station based bias factors are spatially interpolated to yield a bias factor map. Reliability of interpolation is assessed by cross validation. The uncorrected CMORPH rainfall images are multiplied by the interpolated bias map to result in bias corrected CMORPH estimates. Findings are evaluated by RMSE, correlation coefficient (r and standard deviation (SD. Results showed existence of bias in the CMORPH rainfall. It is found that the 7 days SW approach performs best for bias correction of CMORPH rainfall. The outcome of this study showed the efficiency of our bias correction approach.
Brandt, Martin; Mbow, Cheikh; Diouf, Abdoul A; Verger, Aleixandre; Samimi, Cyrus; Fensholt, Rasmus
After a dry period with prolonged droughts in the 1970s and 1980s, recent scientific outcome suggests that the decades of abnormally dry conditions in the Sahel have been reversed by positive anomalies in rainfall. Various remote sensing studies observed a positive trend in vegetation greenness over the last decades which is known as the re-greening of the Sahel. However, little investment has been made in including long-term ground-based data collections to evaluate and better understand the biophysical mechanisms behind these findings. Thus, deductions on a possible increment in biomass remain speculative. Our aim is to bridge these gaps and give specifics on the biophysical background factors of the re-greening Sahel. Therefore, a trend analysis was applied on long time series (1987-2013) of satellite-based vegetation and rainfall data, as well as on ground-observations of leaf biomass of woody species, herb biomass, and woody species abundance in different ecosystems located in the Sahel zone of Senegal. We found that the positive trend observed in satellite vegetation time series (+36%) is caused by an increment of in situ measured biomass (+34%), which is highly controlled by precipitation (+40%). Whereas herb biomass shows large inter-annual fluctuations rather than a clear trend, leaf biomass of woody species has doubled within 27 years (+103%). This increase in woody biomass did not reflect on biodiversity with 11 of 16 woody species declining in abundance over the period. We conclude that the observed greening in the Senegalese Sahel is primarily related to an increasing tree cover that caused satellite-driven vegetation indices to increase with rainfall reversal. © 2014 John Wiley & Sons Ltd.
Bhatti, Haris Akram; Rientjes, Tom; Haile, Alemseged Tamiru; Habib, Emad; Verhoef, Wouter
With the advances in remote sensing technology, satellite-based rainfall estimates are gaining attraction in the field of hydrology, particularly in rainfall-runoff modeling. Since estimates are affected by errors correction is required. In this study, we tested the high resolution National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Centre (CPC) morphing technique (CMORPH) satellite rainfall product (CMORPH) in the Gilgel Abbey catchment, Ethiopia. CMORPH data at 8 km-30 min resolution is aggregated to daily to match in-situ observations for the period 2003–2010. Study objectives are to assess bias of the satellite estimates, to identify optimum window size for application of bias correction and to test effectiveness of bias correction. Bias correction factors are calculated for moving window (MW) sizes and for sequential windows (SW’s) of 3, 5, 7, 9, …, 31 days with the aim to assess error distribution between the in-situ observations and CMORPH estimates. We tested forward, central and backward window (FW, CW and BW) schemes to assess the effect of time integration on accumulated rainfall. Accuracy of cumulative rainfall depth is assessed by Root Mean Squared Error (RMSE). To systematically correct all CMORPH estimates, station based bias factors are spatially interpolated to yield a bias factor map. Reliability of interpolation is assessed by cross validation. The uncorrected CMORPH rainfall images are multiplied by the interpolated bias map to result in bias corrected CMORPH estimates. Findings are evaluated by RMSE, correlation coefficient (r) and standard deviation (SD). Results showed existence of bias in the CMORPH rainfall. It is found that the 7 days SW approach performs best for bias correction of CMORPH rainfall. The outcome of this study showed the efficiency of our bias correction approach. PMID:27314363
Borne, Frédéric; Viennois, Gaëlle
Remote sensing classification methods mostly use only the physical properties of pixels or complex texture indexes but do not lead to recommendation for practical applications. Our objective was to design a texture-based method, called the Paysages A PRIori method (PAPRI), which works both at pixel and neighborhood level and which can handle different spatial scales of analysis. The aim was to stay close to the logic of a human expert and to deal with co-occurrences in a more efficient way than other methods. The PAPRI method is pixelwise and based on a comparison of statistical and spatial reference properties provided by the expert with local properties computed in varying size windows centered on the pixel. A specific distance is computed for different windows around the pixel and a local minimum leads to choosing the class in which the pixel is to be placed. The PAPRI method brings a significant improvement in classification quality for different kinds of images, including aerial, lidar, high-resolution satellite images as well as texture images from the Brodatz and Vistex databases. This work shows the importance of texture analysis in understanding remote sensing images and for future developments.
Shi, Yeyin; Murray, Seth C.; Rooney, William L.; Valasek, John; Olsenholler, Jeff; Pugh, N. Ace; Henrickson, James; Bowden, Ezekiel; Zhang, Dongyan; Thomasson, J. Alex
Recent development of unmanned aerial systems has created opportunities in automation of field-based high-throughput phenotyping by lowering flight operational cost and complexity and allowing flexible re-visit time and higher image resolution than satellite or manned airborne remote sensing. In this study, flights were conducted over corn and sorghum breeding trials in College Station, Texas, with a fixed-wing unmanned aerial vehicle (UAV) carrying two multispectral cameras and a high-resolution digital camera. The objectives were to establish the workflow and investigate the ability of UAV-based remote sensing for automating data collection of plant traits to develop genetic and physiological models. Most important among these traits were plant height and number of plants which are currently manually collected with high labor costs. Vegetation indices were calculated for each breeding cultivar from mosaicked and radiometrically calibrated multi-band imagery in order to be correlated with ground-measured plant heights, populations and yield across high genetic-diversity breeding cultivars. Growth curves were profiled with the aerial measured time-series height and vegetation index data. The next step of this study will be to investigate the correlations between aerial measurements and ground truth measured manually in field and from lab tests.
Goldman, Marvin; Ustin, Susan [University of California, Laboratory for Energy-related Health Research, CA (United States); Warman, Edward A [Stone and Webster Engineering Corp., Boston, MA (United States)
Radiation-induced damage in conifers adjacent to the damaged Chernobyl nuclear power plant has been evaluated using LANDSAT Thematic Mapper satellite images. Eight images acquired between April 22, 1986 and May 15, 1987 were used to assess the extent and magnitude of radiation effects on pine trees within 10 km of the reactor site. The timing and spatial extent of vegetation damaged was used to estimate the radiation doses in the near field around the Chernobyl nuclear power station and to derive dose rates as a function of time during and after the accident. A normalized vegetation index was developed from the TM spectral band data to visually demonstrate the damage and mortality to nearby conifer stands. The earliest date showing detectable injury 1 km west of the reactor unit was June 16, 1986. Subsequent dates revealed continued expansion of the affected areas to the west, north, and south. The greatest aerial expansion of this area occurred by October 15, 1986, with vegetation changes evident up to 5 km west, 2 km south, and 2 km north of the damaged Reactor Unit 4. By May 11, 1987, further scene changes were due principally to removal and mitigation efforts by the Soviet authorities. Areas showing spectral evidence of vegetation damage during the previous growing season do not show evidence of recovery and reflectance in the TM Bands 4 and 3 remain higher than surrounding vegetation, which infers that the trees are dead. The patterns of spectral change indicative of vegetation stress are consistent with changes expected for radiation injury and mortality. The extent and the timing of these effects enabled developing an integrated radiation dose estimate, which was combined with the information regarding the characteristics of radionuclide mix to provide an estimate of maximum dose rates during the early period of the accident. The derived peak dose rates during the 10-day release in the accident are high and are estimated at about 0.5 to 1 rad per hour. These
Sheffield, J.; Lobell, D. B.; Wood, E. F.
Monitoring drought globally is challenging because of the lack of dense in-situ hydrologic data in many regions. In particular, soil moisture measurements are absent in many regions and in real time. This is especially problematic for developing regions such as Africa where water information is arguably most needed, but virtually non-existent on the ground. With the emergence of remote sensing estimates of all components of the water cycle there is now the potential to monitor the full terrestrial water cycle from space to give global coverage and provide the basis for drought monitoring. These estimates include microwave-infrared merged precipitation retrievals, evapotranspiration based on satellite radiation, temperature and vegetation data, gravity recovery measurements of changes in water storage, microwave based retrievals of soil moisture and altimetry based estimates of lake levels and river flows. However, many challenges remain in using these data, especially due to biases in individual satellite retrieved components, their incomplete sampling in time and space, and their failure to provide budget closure in concert. A potential way forward is to use modeling to provide a framework to merge these disparate sources of information to give physically consistent and spatially and temporally continuous estimates of the water cycle and drought. Here we present results from our experimental global water cycle monitor and its African drought monitor counterpart (http://hydrology.princeton.edu/monitor). The system relies heavily on satellite data to drive the Variable Infiltration Capacity (VIC) land surface model to provide near real-time estimates of precipitation, evapotranspiraiton, soil moisture, snow pack and streamflow. Drought is defined in terms of anomalies of soil moisture and other hydrologic variables relative to a long-term (1950-2000) climatology. We present some examples of recent droughts and how they are identified by the system, including
The NASA Operational Simulator for Small Satellites (NOS3) is a suite of tools to aid in areas such as software development, integration test (IT), mission operations training, verification and validation (VV), and software systems check-out. NOS3 provides a software development environment, a multi-target build system, an operator interface-ground station, dynamics and environment simulations, and software-based hardware models. NOS3 enables the development of flight software (FSW) early in the project life cycle, when access to hardware is typically not available. For small satellites there are extensive lead times on many of the commercial-off-the-shelf (COTS) components as well as limited funding for engineering test units (ETU). Considering the difficulty of providing a hardware test-bed to each developer tester, hardware models are modeled based upon characteristic data or manufacturers data sheets for each individual component. The fidelity of each hardware models is such that FSW executes unaware that physical hardware is not present. This allows binaries to be compiled for both the simulation environment, and the flight computer, without changing the FSW source code. For hardware models that provide data dependent on the environment, such as a GPS receiver or magnetometer, an open-source tool from NASA GSFC (42 Spacecraft Simulation) is used to provide the necessary data. The underlying infrastructure used to transfer messages between FSW and the hardware models can also be used to monitor, intercept, and inject messages, which has proven to be beneficial for VV of larger missions such as James Webb Space Telescope (JWST). As hardware is procured, drivers can be added to the environment to enable hardware-in-the-loop (HWIL) testing. When strict time synchronization is not vital, any number of combinations of hardware components and software-based models can be tested. The open-source operator interface used in NOS3 is COSMOS from Ball Aerospace. For
It has become known that lightning activity represents the thunderstorm activity, namely, the intensity and area of precipitation and/or updraft. Thunderstorm is also important as a proxy of the energy input from ocean to atmosphere in typhoon, meaning that if we could monitor the thunderstorm with lightning we could predict the maximum wind velocity near the typhoon center by one or two days before. Constructing ELF and VLF radio wave observation network in Southeast Asia (AVON) and a regional dense network of automated weather station in a big city, we plan to establish the monitoring system for thunderstorm development in western pacific warm pool (WPWP) where typhoon is formed and in detail in big city area. On the other hand, some developing countries in SE-Asia are going to own micro-satellites dedicated to meteorological remote sensing. Making use of the lightning activity data measured by the ground-based networks, and information on 3-D structures of thunderclouds observed by the flexible on-demand operation of the remote-sensing micro-satellites, we would establish a new methodology to obtain very detail semi-real time information that cannot be achieved only with existing observation facilities, such as meteorological radar or large meteorological satellite. Using this new system we try to issue nowcast for the local thunderstorm and for typhoons. The first attempt will be carried out in Metro Manila in Philippines and WPWP as one of the SATREPS projects.
Casana, Jesse; Laugier, Elise Jakoby
Since the start of the Syrian civil war in 2011, the rich archaeological heritage of Syria and northern Iraq has faced severe threats, including looting, combat-related damage, and intentional demolition of monuments. However, the inaccessibility of the conflict zone to archaeologists or cultural heritage specialists has made it difficult to produce accurate damage assessments, impeding efforts to develop mitigation strategies and policies. This paper presents results of a project, undertaken in collaboration with the American Schools of Oriental Research (ASOR) and the US Department of State, to monitor damage to archaeological sites in Syria, northern Iraq, and southern Turkey using recent, high-resolution satellite imagery. Leveraging a large database of archaeological and heritage sites throughout the region, as well as access to continually updated satellite imagery from DigitalGlobe, this project has developed a flexible and efficient methodology to log observations of damage in a manner that facilitates spatial and temporal queries. With nearly 5000 sites carefully evaluated, analysis reveals unexpected patterns in the timing, severity, and location of damage, helping us to better understand the evolving cultural heritage crisis in Syria and Iraq. Results also offer a model for future remote sensing-based archaeological and heritage monitoring efforts in the Middle East and beyond.
Full Text Available Since the start of the Syrian civil war in 2011, the rich archaeological heritage of Syria and northern Iraq has faced severe threats, including looting, combat-related damage, and intentional demolition of monuments. However, the inaccessibility of the conflict zone to archaeologists or cultural heritage specialists has made it difficult to produce accurate damage assessments, impeding efforts to develop mitigation strategies and policies. This paper presents results of a project, undertaken in collaboration with the American Schools of Oriental Research (ASOR and the US Department of State, to monitor damage to archaeological sites in Syria, northern Iraq, and southern Turkey using recent, high-resolution satellite imagery. Leveraging a large database of archaeological and heritage sites throughout the region, as well as access to continually updated satellite imagery from DigitalGlobe, this project has developed a flexible and efficient methodology to log observations of damage in a manner that facilitates spatial and temporal queries. With nearly 5000 sites carefully evaluated, analysis reveals unexpected patterns in the timing, severity, and location of damage, helping us to better understand the evolving cultural heritage crisis in Syria and Iraq. Results also offer a model for future remote sensing-based archaeological and heritage monitoring efforts in the Middle East and beyond.
Houborg, Rasmus; Cescatti, Alessandro; Gitelson, Anatoly A.
variability exists. Satellite remote sensing can support modeling efforts by offering distributed information on important land surface characteristics, which would be very difficult to obtain otherwise. This study investigates the utility of satellite based
Dec 2, 2017 ... State Key Laboratory of Remote Sensing Science, Faculty of Geographical Science, Beijing Normal University, ... factors. Remote sensing has provided many land surface biophysical ...... at the landscape scale; Can. J. Rem.
Wu, Guiping; Liu, Yuanbo
Poyang Lake is the largest freshwater lake in China, with high morphological complexity from south to north. In recent years, the lake has experienced expansion and shrinkage processes over both short- and long-term scales, resulting in significant hydrological, ecological and economic problems. Exactly how and how rapidly the processes of spatial change have occurred in the lake during the expansion and shrinkage periods is unknown. Such knowledge is of great importance for policymakers as it may help with flood/drought prevention, land use planning and lake ecological conservation. In this study, we investigated the spatial-temporal distribution and changing processes of inundation in Poyang Lake based on Moderate Resolution Imaging Spectroradiometer (MODIS) Level-1B data from 2000 to 2011. A defined water variation rate (WVR) and inundation frequency (IF) indicator revealed the water surface submersion and exposure processes of lake expansion and shrinkage in different zones which were divided according to the lake's hydrological and topographic features. Regional differences and significant seasonality variability were found in the annual and monthly mean IF. The monthly mean IF increased slowly from north to south during January-August but decreased quickly from south to north during September-December. During the lake expansion period, the lake-type water body zone (Zone II) had the fastest expansion rate, with a mean monthly WVR value of 34.47% in February-March, and was followed by the channel-type water body zone (Zone I) in March-May (22.47%). However, during the lake shrinkage period, rapid shrinkage first appeared around the alluvial delta zones in August-October. The sequence of lake surface shrinkage from August to December is exactly opposite to that of lake expansion from February to July. These complex inundation characteristics and changing process were driven by the high temporal variability of the river flows, the morphological diversity of the
Photovoltaic (PV) technology is an attractive source of power for systems without connection to power grid. Because of seasonal variations of solar radiation, design of such a power system requires careful analysis in order to provide required reliability. In this paper we present results of three-year measurements of experimental PV system located in Poland and based on polycrystalline silicon module. Irradiation values calculated from results of ground measurements have been compared with data from solar radiation databases employ calculations from of satellite observations. Good convergence level of both data sources has been shown, especially during summer. When satellite data from the same time period is available, yearly and monthly production of PV energy can be calculated with 2% and 5% accuracy, respectively. However, monthly production during winter seems to be overestimated, especially in January. Results of this work may be helpful in forecasting performance of similar PV systems in Central Europe and allow to make more precise forecasts of PV system performance than based only on tables with long time averaged values.
Davalle, Daniele; Cassettari, Riccardo; Saponara, Sergio; Fanucci, Luca; Cucchi, Luca; Bigongiari, Franco; Errico, Walter
This paper presents STAR, a flexible Telemetry, Tracking & Command (TT&C) transponder for Earth Observation (EO) small satellites, developed in collaboration with INTECS and SITAEL companies. With respect to state-of-the-art EO transponders, STAR includes the possibility of scientific data transfer thanks to the 40 Mbps downlink data-rate. This feature represents an important optimization in terms of hardware mass, which is important for EO small satellites. Furthermore, in-flight re-configurability of communication parameters via telecommand is important for in-orbit link optimization, which is especially useful for low orbit satellites where visibility can be as short as few hundreds of seconds. STAR exploits the principles of digital radio to minimize the analog section of the transceiver. 70MHz intermediate frequency (IF) is the interface with an external S/X band radio-frequency front-end. The system is composed of a dedicated configurable high-speed digital signal processing part, the Signal Processor (SP), described in technology-independent VHDL working with a clock frequency of 184.32MHz and a low speed control part, the Control Processor (CP), based on the 32-bit Gaisler LEON3 processor clocked at 32 MHz, with SpaceWire and CAN interfaces. The quantization parameters were fine-tailored to reach a trade-off between hardware complexity and implementation loss which is less than 0.5 dB at BER = 10-5 for the RX chain. The IF ports require 8-bit precision. The system prototype is fitted on the Xilinx Virtex 6 VLX75T-FF484 FPGA of which a space-qualified version has been announced. The total device occupation is 82 %.
Schroeder, R; Rawlins, M A; McDonald, K C; Podest, E; Zimmermann, R; Kueppers, M
Wetlands are not only primary producers of atmospheric greenhouse gases but also possess unique features that are favourable for application of satellite microwave remote sensing to monitoring their status and trend. In this study we apply combined passive and active microwave remote sensing data sets from the NASA sensors AMSR-E and QuikSCAT to map surface water dynamics over Northern Eurasia. We demonstrate our method on the evolution of large wetland complexes for two consecutive years from January 2006 to December 2007. We apply river discharge measurements from the Ob River along with land surface runoff simulations derived from the Pan-Arctic Water Balance Model during and after snowmelt in 2006 and 2007 to interpret the abundance of widespread flooding along the River Ob in early summer of 2007 observed in the remote sensing products. The coarse-resolution, 25 km, surface water product is compared to a high-resolution, 30 m, inundation map derived from ALOS PALSAR (Advanced Land Observation Satellite phased array L-band synthetic aperture radar) imagery acquired for 11 July 2006, and extending along a transect in the central Western Siberian Plain. We found that the surface water fraction derived from the combined AMSR-E/QuikSCAT data sets closely tracks the inundation mapped using higher-resolution ALOS PALSAR data.
Full Text Available Remote sensing technologies have been widely applied in urban environments’ monitoring, synthesis and modeling. Incorporating spatial information in perceptually coherent regions, superpixel-based approaches can effectively eliminate the “salt and pepper” phenomenon which is common in pixel-wise approaches. Compared with fixed-size windows, superpixels have adaptive sizes and shapes for different spatial structures. Moreover, superpixel-based algorithms can significantly improve computational efficiency owing to the greatly reduced number of image primitives. Hence, the superpixel algorithm, as a preprocessing technique, is more and more popularly used in remote sensing and many other fields. In this paper, we propose a superpixel segmentation algorithm called Superpixel Segmentation with Local Competition (SSLC, which utilizes a local competition mechanism to construct energy terms and label pixels. The local competition mechanism leads to energy terms locality and relativity, and thus, the proposed algorithm is less sensitive to the diversity of image content and scene layout. Consequently, SSLC could achieve consistent performance in different image regions. In addition, the Probability Density Function (PDF, which is estimated by Kernel Density Estimation (KDE with the Gaussian kernel, is introduced to describe the color distribution of superpixels as a more sophisticated and accurate measure. To reduce computational complexity, a boundary optimization framework is introduced to only handle boundary pixels instead of the whole image. We conduct experiments to benchmark the proposed algorithm with the other state-of-the-art ones on the Berkeley Segmentation Dataset (BSD and remote sensing images. Results demonstrate that the SSLC algorithm yields the best overall performance, while the computation time-efficiency is still competitive.
Liu, Jiayin; Tang, Zhenmin; Cui, Ying; Wu, Guoxing
Remote sensing technologies have been widely applied in urban environments' monitoring, synthesis and modeling. Incorporating spatial information in perceptually coherent regions, superpixel-based approaches can effectively eliminate the "salt and pepper" phenomenon which is common in pixel-wise approaches. Compared with fixed-size windows, superpixels have adaptive sizes and shapes for different spatial structures. Moreover, superpixel-based algorithms can significantly improve computational efficiency owing to the greatly reduced number of image primitives. Hence, the superpixel algorithm, as a preprocessing technique, is more and more popularly used in remote sensing and many other fields. In this paper, we propose a superpixel segmentation algorithm called Superpixel Segmentation with Local Competition (SSLC), which utilizes a local competition mechanism to construct energy terms and label pixels. The local competition mechanism leads to energy terms locality and relativity, and thus, the proposed algorithm is less sensitive to the diversity of image content and scene layout. Consequently, SSLC could achieve consistent performance in different image regions. In addition, the Probability Density Function (PDF), which is estimated by Kernel Density Estimation (KDE) with the Gaussian kernel, is introduced to describe the color distribution of superpixels as a more sophisticated and accurate measure. To reduce computational complexity, a boundary optimization framework is introduced to only handle boundary pixels instead of the whole image. We conduct experiments to benchmark the proposed algorithm with the other state-of-the-art ones on the Berkeley Segmentation Dataset (BSD) and remote sensing images. Results demonstrate that the SSLC algorithm yields the best overall performance, while the computation time-efficiency is still competitive.
Geli, H. M. E.; Hain, C.; Anderson, M. C.; Senay, G. B.
Recent research findings on modeling actual evapotranspiration (ET) using remote sensing data and methods have proven the ability of these methods to address wide range of hydrological and water resources issues including river basin water balance for improved water resources management, drought monitoring, drought impact and socioeconomic responses, agricultural water management, optimization of land-use for water conservations, water allocation agreement among others. However, there is still a critical need to identify appropriate type of ET information that can address each of these issues. The current trend of increasing demand for water due to population growth coupled with variable and limited water supply due to drought especially in arid and semiarid regions with limited water supply have highlighted the need for such information. To properly address these issues different spatial and temporal resolutions of ET information will need to be used. For example, agricultural water management applications require ET information at field (30-m) and daily time scales while for river basin hydrologic analysis relatively coarser spatial and temporal scales can be adequate for such regional applications. The objective of this analysis is to evaluate the potential of using an integrated ET information that can be used to address some of these issues collectively. This analysis will highlight efforts to address some of the issues that are applicable to New Mexico including assessment of statewide water budget as well as drought impact and socioeconomic responses which all require ET information but at different spatial and temporal scales. This analysis will provide an evaluation of four remote sensing based ET models including ALEXI, DisALEXI, SSEBop, and SEBAL3.0. The models will be compared with ground-based observations from eddy covariance towers and water balance calculations. Remote sensing data from Landsat, MODIS, and VIIRS sensors will be used to provide ET
Claydon, C. R.
The conceptual design of an automated satellite design data base system is presented. The satellite catalog in the system includes data for all earth orbital satellites funded to the hardware stage for launch between 1970 and 1980, and provides a concise compilation of satellite capabilities and design parameters. The cost of satellite subsystems and components will be added to the base. Data elements are listed and discussed. Sensor and science and applications opportunities catalogs will be included in the data system. Capabilities of the BASIS storage, retrieval, and analysis system are used in the system design.
National Aeronautics and Space Administration — This dataset consists of ground-based Global Navigation Satellite System (GNSS) GLObal NAvigation Satellite System (GLONASS) Broadcast Ephemeris Data (hourly files)...
Jensen, Thomas B.S.; Gill, Rashpal S.; Overgaard, Søren
This contribution presents the initial results from experiments with detection of weather radar clutter by information fusion with satellite based nowcasting products. Previous studies using information fusion of weather radar data and first generation Meteosat imagery have shown promising results...... for the detecting and removal of clutter. Naturally, the improved spatio-temporal resolution of the Meteosat Second Generation sensors, coupled with its increased number of spectral bands, is expected to yield even better detection accuracies. Weather radar data from three C-band Doppler weather radars...... Application Facility' of EUMETSAT and is based on multispectral images from the SEVIRI sensor of the Meteosat-8 platform. Of special interest is the 'Precipitating Clouds' product, which uses the spectral information coupled with surface temperatures from Numerical Weather Predictions to assign probabilities...
You, Y.; Wang, S.; Yang, Q.; Shen, M.; Chen, G.
Alpine river water environment on the Plateau (such as Tibetan Plateau, China) is a key indicator for water security and environmental security in China. Due to the complex terrain and various surface eco-environment, it is a very difficult to monitor the water environment over the complex land surface of the plateau. The increasing availability of remote sensing techniques with appropriate spatiotemporal resolutions, broad coverage and low costs allows for effective monitoring river water environment on the Plateau, particularly in remote and inaccessible areas where are lack of in situ observations. In this study, we propose a remote sense-based monitoring model by using multi-platform remote sensing data for monitoring alpine river environment. In this study some parameterization methodologies based on satellite remote sensing data and field observations have been proposed for monitoring the water environmental parameters (including chlorophyll-a concentration (Chl-a), water turbidity (WT) or water clarity (SD), total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC)) over the china's southwest highland rivers, such as the Brahmaputra. First, because most sensors do not collect multiple observations of a target in a single pass, data from multiple orbits or acquisition times may be used, and varying atmospheric and irradiance effects must be reconciled. So based on various types of satellite data, at first we developed the techniques of multi-sensor data correction, atmospheric correction. Second, we also built the inversion spectral database derived from long-term remote sensing data and field sampling data. Then we have studied and developed a high-precision inversion model over the southwest highland river backed by inversion spectral database through using the techniques of multi-sensor remote sensing information optimization and collaboration. Third, take the middle reaches of the Brahmaputra river as the study area, we validated the key
Opgenoorth, H.J.; Kirkwood, S.
The instrumentation and the orbit of the Viking satellite made this first Swedish satellite mission ideally suited for coordinated observations with the dense network of ground-based stations in northern Scandinavia. Several arrays of complementing instruments such as magnetometers, all-sky cameras, riometers and doppler radars monitored on a routine basis the ionosphere under the magnetospheric region passed by Viking. For a large number of orbits the Viking passages close to Scandinavia were covered by the operation of specially designed programmes at the European incoherent-scatter facility (EISCAT). First results of coordinated observations on the ground and aboard Viking have shed new light on the most spectacular feature of substorm expansion, the westward-travelling surge. The end of a substorm and the associated decay of a westward-travelling surge have been analysed. EISCAT measurements of high spatial and temporal resolution indicate that the conductivities and electric fields associated with westward-travelling surges are not represented correctly by the existing models. (author)
Full Text Available In this study we present calibration/validation activities associated with satellite MERIS image processing and aimed at estimatingchl a and CDOM in the Curonian Lagoon. Field data were used to validate the performances of two atmospheric correction algorithms,to build a band-ratio algorithm for chl a and to validate MERIS-derived maps. The neural network-based Case 2 Regional processor wasfound suitable for mapping CDOM; for chl a the band-ratio algorithm applied to image data corrected with the 6S code was found moreappropriate. Maps were in agreement with in situ measurements.This study confirmed the importance of atmospheric correction to estimate water quality and demonstrated the usefulness ofMERIS in investigating eutrophic aquatic ecosystems.
Full Text Available One of economically important fish in the Bay of Bone is Skipjack tuna which their distribution and migration are influenced by surrounding environment. This study aims to investigate the relationship between skipjack tuna and their environments, and to predict potential fishing zones (PFZs for the fish in the Bone Bay-Flores Sea using satellite-based oceanography and catch data. Generalized additive models (GAMs were used to assess the relationship. A generalized linear model(GLM constructed from GAMs was used for prediction. Monthly mean sea surface temperature (SST and chlorophyll-a during the northwest monsoon (December-January together with catch data were used for the year 2012-2013. We used the GAMs to assess the effect of the environment variables on skipjack tuna CPUE (catch per unit effort. The best GLM was selected to predict skipjack tuna abundance. Results indicated that the highest CPUEs (fish/trip occurred in areas where SST and chlorophyll-a ranged from 29.5°-31.5°C and 0.15 - 0.25 mg m-3, respectively. The PFZs for skipjack were closely related to the spatial distribution of the optimum oceanographic conditions and these mainly developed in three locations, northern area of Bone Bay in December, in the middle area of the bay (4°-5.5°S and 120.5°-121.5°E during January and moved to the Flores Sea in February. The movement of skipjack concentration was consistent with the fishery data. This suggests that the dynamics of the optimum oceanographic signatures provided a good indicator for predicting feeding grounds as hotspot areas for skipjack tuna in Bone Bay-Flores Sea during northwest monsoon. Keywords: skipjack tuna, potential fishing zones, satellite based-oceanographic data, Northwest monsoon
Cui, J.; Zhang, S.; Zhang, J.; Shen, X.; Ding, R.; Xu, S.
As of the latest technical methods, hyperspectral remote sensing technology has been widely used in each brach of the geosciences. However, it is still a blank for using the hyperspectral remote sensing to study the active structrure. Hyperspectral remote sensing, with high spectral resolution, continuous spectrum, continuous spatial data, low cost, etc, has great potentialities in the areas of stratum division and fault identification. Blind fault identification in plains and invisible fault discrimination in loess strata are the two hot problems in the current active fault research. Thus, the study of active fault based on the hyperspectral technology has great theoretical significance and practical value. Magnetic susceptibility (MS) records could reflect the rhythm alteration of the formation. Previous study shown that MS has correlation with spectral feature. In this study, the Emaokou section, located to the northwest of the town of Huairen, in Shanxi Province, has been chosen for invisible fault study. We collected data from the Emaokou section, including spectral data, hyperspectral image, MS data. MS models based on spectral features were established and applied to the UHD185 image for MS mapping. The results shown that MS map corresponded well to the loess sequences. It can recognize the stratum which can not identity by naked eyes. Invisible fault has been found in this section, which is useful for paleoearthquake analysis. The faults act as the conduit for migration of terrestrial gases, the fault zones, especially the structurally weak zones such as inrtersections or bends of fault, may has different material composition. We take Xiadian fault for study. Several samples cross-fault were collected and these samples were measured by ASD Field Spec 3 spectrometer. Spectral classification method has been used for spectral analysis, we found that the spectrum of the fault zone have four special spectral region(550-580nm, 600-700nm, 700-800nm and 800-900nm
Gao, Zhiqiang; He, Lingsong; Su, Wei; Wang, Can; Zhang, Changfan
The promising potential of cloud computing and its convergence with technologies such as cloud storage, cloud push, mobile computing allows for creation and delivery of newer type of cloud service. Combined with the thought of cloud computing, this paper presents a cloud-based remote measurement and analysis system. This system mainly consists of three parts: signal acquisition client, web server deployed on the cloud service, and remote client. This system is a special website developed using asp.net and Flex RIA technology, which solves the selective contradiction between two monitoring modes, B/S and C/S. This platform supplies customer condition monitoring and data analysis service by Internet, which was deployed on the cloud server. Signal acquisition device is responsible for data (sensor data, audio, video, etc.) collection and pushes the monitoring data to the cloud storage database regularly. Data acquisition equipment in this system is only conditioned with the function of data collection and network function such as smartphone and smart sensor. This system's scale can adjust dynamically according to the amount of applications and users, so it won't cause waste of resources. As a representative case study, we developed a prototype system based on Ali cloud service using the rotor test rig as the research object. Experimental results demonstrate that the proposed system architecture is feasible.
Vrancken, D.; Paijmans, B.; Fussen, D.; Neefs, E.; Loodts, N.; Dekemper, E.; Vahellemont, F.; Devos, L.; Moelans, W.; Nevejans, D.; Schroeven-Deceuninck, H.; Bernaerts, D.; Zender, J.
There is more and more interest in the understanding and the monitoring of the physics and chemistry of the Earth's atmosphere and its impact on the climate change. Currently a significantly high number of sounders provide the required data to monitor the changes in atmosphere composition, but a dramatic drop in operational atmosphere monitoring missions is expected around 2010. This drop is mainly visible in sounders capable of a high vertical resolution. Currently, instruments on ENVISAT and METOP provide relevant data but this is envisaged to be insufficient to ensure full spatial and temporal coverage and redundancy in the measurement data set. ALTIUS (Atmospheric Limb Tracker for the Investigation of the Upcoming Stratosphere) is a remote sounding experiment proposed by the Belgian Institute for Space Aeronomy (BIRA/IASB) for which a feasibility study was initiated with BELSPO (Belgian Science Policy) and ESA support. The main objective of this study phase was to establish a mission concept, to define the required payload and to establish a satellite platform design. The study was led by the BIRA/IASB team and performed in close collaboration with OIP (payload developer) and Verhaert Space (spacecraft developer). The mission scenario includes bright limb observations in basically all directions, solar occultations around the terminator passages and star occultations during eclipse. These observation modes allow imaging the atmosphere with a high vertical resolution. The spacecraft will be operated in a 10:00 sun-synchronous orbit at an altitude of 695 km, allowing a 3-day revisit time. The envisaged payload for the ALTIUS mission is an imaging spectrometer, observing in the UV, the VIS and the NIR spectral ranges. For each spectral range, an AOTF (Acousto-Optical Tunable Filter) will permit to perform observations of selectable small wavelength domains. A typical set of 10 wavelengths will be recorded within 1 second. The different operational modes impose a
Lei, Sen; Zou, Zhengxia; Liu, Dunge; Xia, Zhenghuan; Shi, Zhenwei
Sea-land segmentation is a key step for the information processing of ocean remote sensing images. Traditional sea-land segmentation algorithms ignore the local similarity prior of sea and land, and thus fail in complex scenarios. In this paper, we propose a new sea-land segmentation method for infrared remote sensing images to tackle the problem based on superpixels and multi-scale features. Considering the connectivity and local similarity of sea or land, we interpret the sea-land segmentation task in view of superpixels rather than pixels, where similar pixels are clustered and the local similarity are explored. Moreover, the multi-scale features are elaborately designed, comprising of gray histogram and multi-scale total variation. Experimental results on infrared bands of Landsat-8 satellite images demonstrate that the proposed method can obtain more accurate and more robust sea-land segmentation results than the traditional algorithms.
Lopez Valencia, Oliver Miguel
The increase in irrigated agriculture in Saudi Arabia is having a large impact on its limited groundwater resources. While large-scale water storage changes can be estimated using satellite data, monitoring groundwater abstraction rates is largely non-existent at either farm or regional level, so water management decisions remain ill-informed. Although determining water use from space at high spatiotemporal resolutions remains challenging, a number of approaches have shown promise, particularly in the retrieval of crop water use via evaporation. Apart from satellite-based estimates, land surface models offer a continuous spatial-temporal evolution of full land-atmosphere water and energy exchanges. In this study, we first examine recent trends in terrestrial water storage depletion within the Arabian Peninsula and explore its relation to increased agricultural activity in the region using satellite data. Next, we evaluate a number of large-scale remote sensing-based evaporation models, giving insight into the challenges of evaporation retrieval in arid environments. Finally, we present a novel method aimed to retrieve groundwater abstraction rates used in irrigated fields by constraining a land surface model with remote sensing-based evaporation observations. The approach is used to reproduce reported irrigation rates over 41 center-pivot irrigation fields presenting a range of crop dynamics over the course of one year. The results of this application are promising, with mean absolute errors below 3 mm:day-1, bias of -1.6 mm:day-1, and a first rough estimate of total annual abstractions of 65.8 Mm3 (close to the estimated value using reported farm data, 69.42 Mm3). However, further efforts to address the overestimation of bare soil evaporation in the model are required. The uneven coverage of satellite data within the study site allowed us to evaluate its impact on the optimization, with a better match between observed and obtained irrigation rates on fields with
Full Text Available Satellite images are an important source of information to identify and analyse some hazardous climatic phenomena such as the dryness and drought. These phenomena are characterized by scarce rainfall, increased evapotranspiration and high soil moisture deficit. The soil water reserve depletes to the wilting coefficient, soon followed by the pedological drought which has negative effects on vegetation and agricultural productivity. The MODIS satellite images (Moderate Resolution Imaging Spectroradiometer allow the monitoring of the vegetation throughout the entire vegetative period, with a frequency of 1-2 days and with a spatial resolution of 250 m, 500 m and 1 km away. Another useful source of information is the LANDSAT satellite images, with a spatial resolution of 30 m. Based on MODIS and Landsat satellite images, were calculated moisture monitoring index such as SIWSI (Shortwave Infrared Water Stress Index. Consequently, some years with low moisture such as 2000, 2002, 2007 and 2012 could be identified. Spatially, the areas with moisture deficit varied from one year to another all over the whole analised period (2000-2012. The remote sensing results was corelated with Standard Precipitation Anomaly, which gives a measure of the severity of a wet or dry event.
Full Text Available 3D building reconstruction from remote sensing image data from satellites is still an active research topic and very valuable for 3D city modelling. The roof model is the most important component to reconstruct the Level of Details 2 (LoD2 for a building in 3D modelling. While the general solution for roof modelling relies on the detailed cues (such as lines, corners and planes extracted from a Digital Surface Model (DSM, the correct detection of the roof type and its modelling can fail due to low quality of the DSM generated by dense stereo matching. To reduce dependencies of roof modelling on DSMs, the pansharpened satellite images as a rich resource of information are used in addition. In this paper, two strategies are employed for roof type classification. In the first one, building roof types are classified in a state-of-the-art supervised pre-trained convolutional neural network (CNN framework. In the second strategy, deep features from deep layers of different pre-trained CNN model are extracted and then an RBF kernel using SVM is employed to classify the building roof type. Based on roof complexity of the scene, a roof library including seven types of roofs is defined. A new semi-automatic method is proposed to generate training and test patches of each roof type in the library. Using the pre-trained CNN model does not only decrease the computation time for training significantly but also increases the classification accuracy.
Full Text Available In this paper we review the status of new applications research of the Japanese Aerospace Exploration Agency (JAXA for global health promotion using information derived from Earth observation data by satellites in cooperation with inter-disciplinary collaborators. Current research effort at JAXA to promote global public health is focused primarily on the use of remote sensing to address two themes: (i prediction models for malaria and cholera in Kenya, Africa; and (ii air quality assessment of small, particulate matter (PM2.5, nitrogen dioxide (NO2 and ozone (O3. Respiratory and cardivascular diseases constitute cross-boundary public health risk issues on a global scale. The authors report here on results of current of a collaborative research to call attention to the need to take preventive measures against threats to public health using newly arising remote sensing information from space.
The satellite-based remote sensing of particulate matter (PM) in support to urban air quality: PM variability and hot spots within the Cordoba city (Argentina) as revealed by the high-resolution MAIAC-algorithm retrievals applied to a ten-years dataset (2
Della Ceca, Lara Sofia; Carreras, Hebe A.; Lyapustin, Alexei I.; Barnaba, Francesca
Particulate matter (PM) is one of the major harmful pollutants to public health and the environment . In developed countries, specific air-quality legislation establishes limit values for PM metrics (e.g., PM10, PM2.5) to protect the citizens health (e.g., European Commission Directive 2008/50, US Clean Air Act). Extensive PM measuring networks therefore exist in these countries to comply with the legislation. In less developed countries air quality monitoring networks are still lacking and satellite-based datasets could represent a valid alternative to fill observational gaps. The main PM (or aerosol) parameter retrieved from satellite is the 'aerosol optical depth' (AOD), an optical parameter quantifying the aerosol load in the whole atmospheric column. Datasets from the MODIS sensors on board of the NASA spacecrafts TERRA and AQUA are among the longest records of AOD from space. However, although extremely useful in regional and global studies, the standard 10 km-resolution MODIS AOD product is not suitable to be employed at the urban scale. Recently, a new algorithm called Multi-Angle Implementation of Atmospheric Correction (MAIAC) was developed for MODIS, providing AOD at 1 km resolution . In this work, the MAIAC AOD retrievals over the decade 2003-2013 were employed to investigate the spatiotemporal variation of atmospheric aerosols over the Argentinean city of Cordoba and its surroundings, an area where a very scarce dataset of in situ PM data is available. The MAIAC retrievals over the city were firstly validated using a 'ground truth' AOD dataset from the Cordoba sunphotometer operating within the global AERONET network . This validation showed the good performances of the MAIAC algorithm in the area. The satellite MAIAC AOD dataset was therefore employed to investigate the 10-years trend as well as seasonal and monthly patterns of particulate matter in the Cordoba city. The first showed a marked increase of AOD over time, particularly evident in
Ouellette, N.; Rogner, H.-H.; Scott, D.S.
This paper examines synergies, opportunities and barriers associated with hydrogen and excess hydro-electricity in remote areas. The work is based on a case study that examined the techno-economic feasibility of a new hydrogen-based industry using surplus/off-peak generating capacity of the Taltson Dam and Generating Station in the Northwest Territories, Canada. After evaluating the amount and cost of hydrogen that could be produced from the excess capacity, the study investigates three hydrogen utilization scenarios: (1) merchant liquid or compressed hydrogen, (2) hydrogen as a chemical feedstock for the production of hydrogen peroxide, (3) methanol production from biomass, oxygen and hydrogen. Hydrogen peroxide production is the most promising and attractive strategy in the Fort Smith context. The study also illustrates patterns that recur in isolated sites throughout the world. (Author)
Schumann, G.; Andreadis, K.; Castillo, C. J.
To date there is no coherent and consistent database on observed or simulated flood event inundation and magnitude at large scales (continental to global). The only compiled data set showing a consistent history of flood inundation area and extent at a near global scale is provided by the MODIS-based Dartmouth Flood Observatory. However, MODIS satellite imagery is only available from 2000 and is hampered by a number of issues associated with flood mapping using optical images (e.g. classification algorithms, cloud cover, vegetation). Here, we present for the first time a proof-of-concept study in which we employ a computationally efficient 2-D hydrodynamic model (LISFLOOD-FP) complemented with a sub-grid channel formulation to generate a complete flood inundation climatology of the past 40 years (1973-2012) for the entire Australian continent. The model was built completely from freely available SRTM-derived data, including channel widths, bank heights and floodplain topography, which was corrected for vegetation canopy height using a global ICESat canopy dataset. Channel hydraulics were resolved using actual channel data and bathymetry was estimated within the model using hydraulic geometry. On the floodplain, the model simulated the flow paths and inundation variables at a 1 km resolution. The developed model was run over a period of 40 years and a floodplain inundation climatology was generated and compared to satellite flood event observations. Our proof-of-concept study demonstrates that this type of model can reliably simulate past flood events with reasonable accuracies both in time and space. The Australian model was forced with both observed flow climatology and VIC-simulated flows in order to assess the feasibility of a model-based flood inundation climatology at the global scale.
Negoda, A.; Bunin, S.; Bushuev, E.; Dranovsky, V.
LEOPACK is yet another LEO satellite project which provides global integrated services for 'business' communications. It utilizes packet rather then circuit switching in both terrestrial and satellite chains as well as cellular approach for frequencies use. Original multiple access protocols and decentralized network control make it possible to organize regionally or logically independent and world-wide networks. Relatively small number of satellites (28) provides virtually global network coverage.
Peterson, David L.; Hammer, Philip; Smith, William H.; Lawless, James G. (Technical Monitor)
Until recent times, optical remote sensing of ecosystem properties from space has been limited to broad band multispectral scanners such as Landsat and AVHRR. While these sensor data can be used to derive important information about ecosystem parameters, they are very limited for measuring key biogeochemical cycling parameters such as the chemical content of plant canopies. Such parameters, for example the lignin and nitrogen contents, are potentially amenable to measurements by very high spectral resolution instruments using a spectroscopic approach. Airborne sensors based on grating imaging spectrometers gave the first promise of such potential but the recent decision not to deploy the space version has left the community without many alternatives. In the past few years, advancements in high performance deep well digital sensor arrays coupled with a patented design for a two-beam interferometer has produced an entirely new design for acquiring imaging spectroscopic data at the signal to noise levels necessary for quantitatively estimating chemical composition (1000:1 at 2 microns). This design has been assembled as a laboratory instrument and the principles demonstrated for acquiring remote scenes. An airborne instrument is in production and spaceborne sensors being proposed. The instrument is extremely promising because of its low cost, lower power requirements, very low weight, simplicity (no moving parts), and high performance. For these reasons, we have called it the first instrument optimized for ecosystem studies as part of a Biological Imaging and Observation Mission to Earth (BIOME).
IACOB I. CIPRIAN
Full Text Available Fractal Dimension of Urban Expansion Based on Remote Sensing Images: In Cluj-Napoca city the process of urbanization has been accelerated during the years and implication of local authorities reflects a relevant planning policy. A good urban planning framework should take into account the society demands and also it should satisfy the natural conditions of local environment. The expansion of antropic areas it can be approached by implication of 5D variables (time as a sequence of stages, space: with x, y, z and magnitude of phenomena into the process, which will allow us to analyse and extract the roughness of city shape. Thus, to improve the decision factor we take a different approach in this paper, looking at geometry and scale composition. Using the remote sensing (RS and GIS techniques we manage to extract a sequence of built-up areas (from 1980 to 2012 and used the result as an input for modelling the spatialtemporal changes of urban expansion and fractal theory to analysed the geometric features. Taking the time as a parameter we can observe behaviour and changes in urban landscape, this condition have been known as self-organized – a condition which in first stage the system was without any turbulence (before the antropic factor and during the time tend to approach chaotic behaviour (entropy state without causing an disequilibrium in the main system.
Miodrag D. Regodić
monitoring natural phenomena The images taken from Remote Sensing have helped men to use the environment and natural resources in a better way. It is expected that the developement of new technologies will spread the usage of satellite images for the welfare of mankind as well. Besides monitoring the surface of the Earth, the satellite monitoring of the processes inside the Earth itself is of great importance since these processes can cause different catastrophes such as earthquakes, volcano eruptions, floods, etc. Usage of satellite images in monitoring atmospheric phenomena The launch of artificial earth satellites has opened new possibilities for monitoring and studying atmospheric phenomena. A large number of meteorological satellites have been launched by now (Nimbus, Meteor, SNS, ESSA, Meteosat, Terra, etc.. Since these images are primarily used for weather forecast, meteorologists use them to get information about the characteristics of clouds related to their temperature, the temperature of the cloud layer, the degree of cloudness, the profiles of humidity content, the wind parameters, etc. Meteosat satellites Meteosat is the first European geostationary satellite designed for meteorological research. The use of these satellites enabled the surveying in the visible and the near IR part of the spectrum as well as in the infrared thermal and water steam track. Based on these images, it was possible to obtain data such as: height of clouds, cloud spreading and moving, sea surface temperature, speed of wind, distribution of the water steam, balance of radiation, etc. Usage of satellite images in monitoring floods Satellite images are an excellent background and an initial phase for preventing severe catastrophic events caused by floods. Due to satellite images, it is possible to manage overflown regions before, during and after floods. This enables prevention, forecasting, detection and elimination of consequences, i.e. demage. Satellite images are of great help
Realmuto, V. J.; Berk, A.; Acharya, P. K.; Kennett, R.
The monitoring of volcanic gas emissions with gas cameras, spectrometer arrays, tethersondes, and UAVs presents new opportunities for the validation of satellite-based retrievals of gas concentrations. Gas cameras and spectrometer arrays provide instantaneous observations of the gas burden, or concentration along an optical path, over broad sections of a plume, similar to the observations acquired by nadir-viewing satellites. Tethersondes and UAVs provide us with direct measurements of the vertical profiles of gas concentrations within plumes. This presentation will focus on our current efforts to validate ASTER-based maps of sulfur dioxide plumes at Turrialba and Kilauea Volcanoes (located in Costa Rica and Hawaii, respectively). These volcanoes, which are the subjects of comprehensive monitoring programs, are challenging targets for thermal infrared (TIR) remote sensing due the warm and humid atmospheric conditions. The high spatial resolution of ASTER in the TIR (90 meters) allows us to map the plumes back to their source vents, but also requires us to pay close attention to the temperature and emissivity of the surfaces beneath the plumes. Our knowledge of the surface and atmospheric conditions is never perfect, and we employ interactive mapping techniques that allow us to evaluate the impact of these uncertainties on our estimates of plume composition. To accomplish this interactive mapping we have developed the Plume Tracker tool kit, which integrates retrieval procedures, visualization tools, and a customized version of the MODTRAN radiative transfer (RT) model under a single graphics user interface (GUI). We are in the process of porting the RT calculations to graphics processing units (GPUs) with the goal of achieving a 100-fold increase in the speed of computation relative to conventional CPU-based processing. We will report on our progress with this evolution of Plume Tracker. Portions of this research were conducted at the Jet Propulsion Laboratory
Meyer, Hanna; Kühnlein, Meike; Appelhans, Tim; Nauss, Thomas
Machine learning (ML) algorithms have successfully been demonstrated to be valuable tools in satellite-based rainfall retrievals which show the practicability of using ML algorithms when faced with high dimensional and complex data. Moreover, recent developments in parallel computing with ML present new possibilities for training and prediction speed and therefore make their usage in real-time systems feasible. This study compares four ML algorithms - random forests (RF), neural networks (NNET), averaged neural networks (AVNNET) and support vector machines (SVM) - for rainfall area detection and rainfall rate assignment using MSG SEVIRI data over Germany. Satellite-based proxies for cloud top height, cloud top temperature, cloud phase and cloud water path serve as predictor variables. The results indicate an overestimation of rainfall area delineation regardless of the ML algorithm (averaged bias = 1.8) but a high probability of detection ranging from 81% (SVM) to 85% (NNET). On a 24-hour basis, the performance of the rainfall rate assignment yielded R2 values between 0.39 (SVM) and 0.44 (AVNNET). Though the differences in the algorithms' performance were rather small, NNET and AVNNET were identified as the most suitable algorithms. On average, they demonstrated the best performance in rainfall area delineation as well as in rainfall rate assignment. NNET's computational speed is an additional advantage in work with large datasets such as in remote sensing based rainfall retrievals. However, since no single algorithm performed considerably better than the others we conclude that further research in providing suitable predictors for rainfall is of greater necessity than an optimization through the choice of the ML algorithm.
Madry, Scott; Camacho-Lara, Sergio
Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...
Pramod Krishna, Akhouri
A watershed in Chhotanagpur plateau region was investigated utilizing space data from Indian Remote Sensing (IRS) Satellite towards spatial and temporal soil erosion process study. Geomorphologically, this plateau region is an undulating pediplain. The watershed namely Potpoto river watershed covering an area of 8160 hectares is situated in the vicinity of Ranchi, capital city of newly created Jharkahnd state. As per the national watershed atlas, Potpoto river is a tributary of Subarnarekha river system within the Upper Subarnarekha river basin under watershed no. 4H3C8. This rural to semi-urban watershed is important towards various services to Ranchi city as well as experiencing direct or indirect pressures of development. Drivers of land use changes at ground level are responsible for change in soil erosion rates in any watershed in coupled human-environment systems. This may adversely affect the soil cover of such watersheds depicted through changed rates of erosion. In a rural to semi-urban watershed like this, there are general tendencies of land use and thereby land cover changes from forests to agricultural lands, within agricultural land in terms of cropping pattern changes to cash-crops, orchards, commercial plantations and conversions to other land use categories as well towards infrastructure expansions. Universal Soil Loss Equation (USLE) was used as a basis to observe the intensity of erosion using remote sensing, rainfall data, soil data and land use/land cover map. IRS1C LISSIII and IRSP6 LISSIII data were used to identify land use status for the years 1996 and 2004 respectively. LISSIII sensor provides data in the visible to near infrared (Bands 2, 3, 4) as well as short wave infrared (Band 5) range of electromagnetic spectrum. In this study, bands 2 (0.52-0.59 microns), 3 (0.62-0.68 microns) and 4 (0.77-0.86 microns) were used with spatial resolution of 23.5 meters at nadir. Digital image processing was carried out using ERDAS Imagine software
Nayak, Munir A.; Villarini, Gabriele
Atmospheric rivers (ARs) play a central role in the hydrology and hydroclimatology of the central United States. More than 25% of the annual rainfall is associated with ARs over much of this region, with many large flood events tied to their occurrence. Despite the relevance of these storms for flood hydrology and water budget, the characteristics of rainfall associated with ARs over the central United has not been investigated thus far. This study fills this major scientific gap by describing the rainfall during ARs over the central United States using five remote sensing-based precipitation products over a 12-year study period. The products we consider are: Stage IV, Tropical Rainfall Measuring Mission - Multi-satellite Precipitation Analysis (TMPA, both real-time and research version); Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN); the CPC MORPHing Technique (CMORPH). As part of the study, we evaluate these products against a rain gauge-based dataset using both graphical- and metrics-based diagnostics. Based on our analyses, Stage IV is found to better reproduce the reference data. Hence, we use it for the characterization of rainfall in ARs. Most of the AR-rainfall is located in a narrow region within ∼150 km on both sides of the AR major axis. In this region, rainfall has a pronounced positive relationship with the magnitude of the water vapor transport. Moreover, we have also identified a consistent increase in rainfall intensity with duration (or persistence) of AR conditions. However, there is not a strong indication of diurnal variability in AR rainfall. These results can be directly used in developing flood protection strategies during ARs. Further, weather prediction agencies can benefit from the results of this study to achieve higher skill of resolving precipitation processes in their models.
Full Text Available Increasingly available and a virtually uninterrupted supply of satellite-estimatedrainfall data is gradually becoming a cost-effective source of input for flood predictionunder a variety of circumstances. However, most real-time and quasi-global satelliterainfall products are currently available at spatial scales ranging from 0.25o to 0.50o andhence, are considered somewhat coarse for dynamic hydrologic modeling of basin-scaleflood events. This study assesses the question: what are the hydrologic implications ofuncertainty of satellite rainfall data at the coarse scale? We investigated this question onthe 970 km2 Upper Cumberland river basin of Kentucky. The satellite rainfall productassessed was NASA’s Tropical Rainfall Measuring Mission (TRMM Multi-satellitePrecipitation Analysis (TMPA product called 3B41RT that is available in pseudo real timewith a latency of 6-10 hours. We observed that bias adjustment of satellite rainfall data canimprove application in flood prediction to some extent with the trade-off of more falsealarms in peak flow. However, a more rational and regime-based adjustment procedureneeds to be identified before the use of satellite data can be institutionalized among floodmodelers.
Teffahi, Hanane; Yao, Hongxun; Belabid, Nasreddine; Chaib, Souleyman
The satellite images with very high spatial resolution have been recently widely used in image classification topic as it has become challenging task in remote sensing field. Due to a number of limitations such as the redundancy of features and the high dimensionality of the data, different classification methods have been proposed for remote sensing images classification particularly the methods using feature extraction techniques. This paper propose a simple efficient method exploiting the capability of extended multi-attribute profiles (EMAP) with sparse autoencoder (SAE) for remote sensing image classification. The proposed method is used to classify various remote sensing datasets including hyperspectral and multispectral images by extracting spatial and spectral features based on the combination of EMAP and SAE by linking them to kernel support vector machine (SVM) for classification. Experiments on new hyperspectral image "Huston data" and multispectral image "Washington DC data" shows that this new scheme can achieve better performance of feature learning than the primitive features, traditional classifiers and ordinary autoencoder and has huge potential to achieve higher accuracy for classification in short running time.
Cable, D. A.; Derocher, W. L., Jr.; Cathcart, J. A.; Keeley, M. G.; Madayev, L.; Nguyen, T. K.; Preese, J. R.
A number of areas of research and laboratory experiments were identified which could lead to development of a cost efficient remote, disable satellite recovery system. Estimates were planned of disabled satellite motion. A concept is defined as a Tumbling Satellite Recovery kit which includes a modular system, composed of a number of subsystem mechanisms that can be readily integrated into varying combinations. This would enable the user to quickly configure a tailored remote, disabled satellite recovery kit to meet a broad spectrum of potential scenarios. The capability was determined of U.S. Earth based satellite tracking facilities to adequately determine the orientation and motion rates of disabled satellites.
Chiu, L.; Hao, X.; Kinter, J. L.; Stearn, G.; Aliani, M.
The launch of GOES-16 series provides an opportunity to advance near real-time applications in natural hazard detection, monitoring and warning. This study demonstrates the capability and values of receiving real-time satellite-based Earth observations over a fast terrestrial networks and processing high-resolution remote sensing data in a university environment. The demonstration system includes 4 components: 1) Near real-time data receiving and processing; 2) data analysis and visualization; 3) event detection and monitoring; and 4) information dissemination. Various tools are developed and integrated to receive and process GRB data in near real-time, produce images and value-added data products, and detect and monitor extreme weather events such as hurricane, fire, flooding, fog, lightning, etc. A web-based application system is developed to disseminate near-real satellite images and data products. The images are generated with GIS-compatible format (GeoTIFF) to enable convenient use and integration in various GIS platforms. This study enhances the capacities for undergraduate and graduate education in Earth system and climate sciences, and related applications to understand the basic principles and technology in real-time applications with remote sensing measurements. It also provides an integrated platform for near real-time monitoring of extreme weather events, which are helpful for various user communities.
Zhao, Wei-hu; Zhao, Jing; Zhao, Shang-hong; Li, Yong-jun; Wang, Xiang; Dong, Yi; Dong, Chen
Optical satellite communication with the advantages of broadband, large capacity and low power consuming broke the bottleneck of the traditional microwave satellite communication. The formation of the Space-based Information System with the technology of high performance optical inter-satellite communication and the realization of global seamless coverage and mobile terminal accessing are the necessary trend of the development of optical satellite communication. Considering the resources, missions and restraints of Data Relay Satellite Optical Communication System, a model of optical communication resources scheduling is established and a scheduling algorithm based on artificial intelligent optimization is put forwarded. According to the multi-relay-satellite, multi-user-satellite, multi-optical-antenna and multi-mission with several priority weights, the resources are scheduled reasonable by the operation: "Ascertain Current Mission Scheduling Time" and "Refresh Latter Mission Time-Window". The priority weight is considered as the parameter of the fitness function and the scheduling project is optimized by the Genetic Algorithm. The simulation scenarios including 3 relay satellites with 6 optical antennas, 12 user satellites and 30 missions, the simulation result reveals that the algorithm obtain satisfactory results in both efficiency and performance and resources scheduling model and the optimization algorithm are suitable in multi-relay-satellite, multi-user-satellite, and multi-optical-antenna recourses scheduling problem.
d'Angelo, P.; Reinartz, P.
High resolution stereo satellite imagery is well suited for the creation of digital surface models (DSM). A system for highly automated and operational DSM and orthoimage generation based on CARTOSAT-1 imagery is presented, with emphasis on fully automated georeferencing. The proposed system processes level-1 stereo scenes using the rational polynomial coefficients (RPC) universal sensor model. The RPC are derived from orbit and attitude information and have a much lower accuracy than the ground resolution of approximately 2.5 m. In order to use the images for orthorectification or DSM generation, an affine RPC correction is required. In this paper, GCP are automatically derived from lower resolution reference datasets (Landsat ETM+ Geocover and SRTM DSM). The traditional method of collecting the lateral position from a reference image and interpolating the corresponding height from the DEM ignores the higher lateral accuracy of the SRTM dataset. Our method avoids this drawback by using a RPC correction based on DSM alignment, resulting in improved geolocation of both DSM and ortho images. Scene based method and a bundle block adjustment based correction are developed and evaluated for a test site covering the nothern part of Italy, for which 405 Cartosat-1 Stereopairs are available. Both methods are tested against independent ground truth. Checks against this ground truth indicate a lateral error of 10 meters.
Pelland, N.; Sterling, J.; Springer, A.; Iverson, S.; Johnson, D.; Lea, M. A.; Bond, N. A.; Ream, R.; Lee, C.; Eriksen, C.
Behavioral responses by top marine predators to oceanographic features such as eddies, river plumes, storms, and coastal topography suggest that biophysical interactions in these zones affect predators' prey, foraging behaviors, and potentially fitness. However, examining these pathways is challenged by the obstacles inherent in obtaining simultaneous observations of surface and subsurface environmental fields and predator behavior. This work describes recent publications and ongoing studies of northern fur seal (NFS) foraging ecology during their 8-month migration. Satellite-tracked movement and dive behavior in the North Pacific ocean was compared to remotely sensed data, atmospheric reanalysis, autonomous in situ ocean sampling, and animal borne temperature and salinity data. Integration of these data demonstrates how reproductive fitness, physiology, and environment shape NFS migratory patterns. Seal mass correlates with dive ability and thus larger males exploit prey aggregating at the base of the winter mixed-layer depth in the Bering Sea and interior northern North Pacific Ocean. Smaller adult females migrate to the Gulf of Alaska and California Current ecosystems - where surface wind speeds decline, mixed-layer depths shoal, and coastal production is fueled by upwelling, coastal capes, and eddies - and less commonly to the Transitional Zone Chlorophyll Front, where fronts and eddies may concentrate prey. Surface wind speed and direction influence movement behavior of all age and size classes, though to a greater degree in the smaller pups and adult females than adult males. For naïve and physiologically less-capable pups, the timing and strength of autumn winds during migratory dispersal may play a role in shaping migratory routes and the environmental conditions faced by pups along these routes. In combination with other factors such as pup condition, this may play a role in interannual variations in overwinter survivorship.
Kampik, Timotheus; Larsen, Frank; Bellika, Johan Gustav
The objective of the study was to identify experiences and attitudes of German and Norwegian general practitioners (GPs) towards Internet-based remote consultation solutions supporting communication between GPs and patients in the context of the German and Norwegian healthcare systems. Interviews with four German and five Norwegian GPs were conducted. The results were qualitatively analyzed. All interviewed GPs stated they would like to make use of Internet-based remote consultations in the future. Current experiences with remote consultations are existent to a limited degree. No GP reported to use a comprehensive remote consultation solution. The main features GPs would like to see in a remote consultation solution include asynchronous exchange of text messages, video conferencing with text chat, scheduling of remote consultation appointments, secure login and data transfer and the integration of the remote consultation solution into the GP's EHR system.
Hasager, Charlotte Bay; Pena Diaz, Alfredo; Christiansen, Merete Bruun
Remote sensing observations used in offshore wind energy are described in three parts: ground-based techniques and applications, airborne techniques and applications, and satellite-based techniques and applications. Ground-based remote sensing of winds is relevant, in particular, for new large wind...
Dong S. Ko
Full Text Available We estimated surface salinity flux and solar penetration from satellite data, and performed model simulations to examine the impact of including the satellite estimates on temperature, salinity, and dissolved oxygen distributions on the Louisiana continental shelf (LCS near the annual hypoxic zone. Rainfall data from the Tropical Rainfall Measurement Mission (TRMM were used for the salinity flux, and the diffuse attenuation coefficient (Kd from Moderate Resolution Imaging Spectroradiometer (MODIS were used for solar penetration. Improvements in the model results in comparison with in situ observations occurred when the two types of satellite data were included. Without inclusion of the satellite-derived surface salinity flux, realistic monthly variability in the model salinity fields was observed, but important inter-annual variability was missed. Without inclusion of the satellite-derived light attenuation, model bottom water temperatures were too high nearshore due to excessive penetration of solar irradiance. In general, these salinity and temperature errors led to model stratification that was too weak, and the model failed to capture observed spatial and temporal variability in water-column vertical stratification. Inclusion of the satellite data improved temperature and salinity predictions and the vertical stratification was strengthened, which improved prediction of bottom-water dissolved oxygen. The model-predicted area of bottom-water hypoxia on the Louisiana shelf, an important management metric, was substantially improved in comparison to observed hypoxic area by including the satellite data.
The paper discusses the development of a data base, the Satellite Climate Diagnostic Data Base (SCDDB), for real time operational climate monitoring utilizing current satellite data. Special attention is given to the satellite-derived quantities useful for monitoring global climate changes, the requirements of SCDDB, and the use of conventional meteorological data and model assimilated data in developing the SCDDB. Examples of prototype SCDDB products are presented. 10 refs
Full Text Available Normally, the status of land cover is inherently dynamic and changing continuously on temporal scale. However, disturbances or abnormal changes of land cover — caused by such as forest fire, flood, deforestation, and plant diseases — occur worldwide at unknown times and locations. Timely detection and characterization of these disturbances is of importance for land cover monitoring. Recently, many time-series-analysis methods have been developed for near real-time or online disturbance detection, using satellite image time series. However, the detection results were only labelled with “Change/ No change” by most of the present methods, while few methods focus on estimating reliability (or confidence level of the detected disturbances in image time series. To this end, this paper propose a statistical analysis method for estimating reliability of disturbances in new available remote sensing image time series, through analysis of full temporal information laid in time series data. The method consists of three main steps. (1 Segmenting and modelling of historical time series data based on Breaks for Additive Seasonal and Trend (BFAST. (2 Forecasting and detecting disturbances in new time series data. (3 Estimating reliability of each detected disturbance using statistical analysis based on Confidence Interval (CI and Confidence Levels (CL. The method was validated by estimating reliability of disturbance regions caused by a recent severe flooding occurred around the border of Russia and China. Results demonstrated that the method can estimate reliability of disturbances detected in satellite image with estimation error less than 5% and overall accuracy up to 90%.
Richardson, Andrew D; Hufkens, Koen; Milliman, Tom; Frolking, Steve
Phenology is a valuable diagnostic of ecosystem health, and has applications to environmental monitoring and management. Here, we conduct an intercomparison analysis using phenological transition dates derived from near-surface PhenoCam imagery and MODIS satellite remote sensing. We used approximately 600 site-years of data, from 128 camera sites covering a wide range of vegetation types and climate zones. During both "greenness rising" and "greenness falling" transition phases, we found generally good agreement between PhenoCam and MODIS transition dates for agricultural, deciduous forest, and grassland sites, provided that the vegetation in the camera field of view was representative of the broader landscape. The correlation between PhenoCam and MODIS transition dates was poor for evergreen forest sites. We discuss potential reasons (including sub-pixel spatial heterogeneity, flexibility of the transition date extraction method, vegetation index sensitivity in evergreen systems, and PhenoCam geolocation uncertainty) for varying agreement between time series of vegetation indices derived from PhenoCam and MODIS imagery. This analysis increases our confidence in the ability of satellite remote sensing to accurately characterize seasonal dynamics in a range of ecosystems, and provides a basis for interpreting those dynamics in the context of tangible phenological changes occurring on the ground.
This report describes an approach for automatic feature detection from fusion of remote sensing imagery using a combination of neural network architecture and the Dempster-Shafer (DS) theory of evidence...
National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetric data derived from a multipectral World View-2 satellite image mosaiced to provide near complete coverage of nearshore terrain around the islands....
development and operationalization of new spill response remote sensing tools must precede the next major oil spill. © 2012 Elsevier Inc. All rights reserved...Environment 124 (2012) 185–209 sensing oil spill impacts, and 5) a final discussion. Each section presents background, available remote sensing tools , and...cialized DaVinci command-line software (Clark et al., 2003) then mapped oil slick volume (Clark et al., 2010) in each AVIRIS pixel by identifying the
Panda, Sudhanshu S.; Rao, Mahesh N.; Thenkabail, Prasad S.; Fitzerald, James E.
The American Society of Photogrammetry and Remote Sensing defined remote sensing as the measurement or acquisition of information of some property of an object or phenomenon, by a recording device that is not in physical or intimate contact with the object or phenomenon under study (Colwell et al., 1983). Environmental Systems Research Institute (ESRI) in its geographic information system (GIS) dictionary defines remote sensing as “collecting and interpreting information about the environment and the surface of the earth from a distance, primarily by sensing radiation that is naturally emitted or reflected by the earth’s surface or from the atmosphere, or by sending signals transmitted from a device and reflected back to it (ESRI, 2014).” The usual source of passive remote sensing data is the measurement of reflected or transmitted electromagnetic radiation (EMR) from the sun across the electromagnetic spectrum (EMS); this can also include acoustic or sound energy, gravity, or the magnetic field from or of the objects under consideration. In this context, the simple act of reading this text is considered remote sensing. In this case, the eye acts as a sensor and senses the light reflected from the object to obtain information about the object. It is the same technology used by a handheld camera to take a photograph of a person or a distant scenic view. Active remote sensing, however, involves sending a pulse of energy and then measuring the returned energy through a sensor (e.g., Radio Detection and Ranging [RADAR], Light Detection and Ranging [LiDAR]). Thermal sensors measure emitted energy by different objects. Thus, in general, passive remote sensing involves the measurement of solar energy reflected from the Earth’s surface, while active remote sensing involves synthetic (man-made) energy pulsed at the environment and the return signals are measured and recorded.
Dong S. Ko; Richard W. Gould; Bradley Penta; John C. Lehrter
We estimated surface salinity flux and solar penetration from satellite data, and performed model simulations to examine the impact of including the satellite estimates on temperature, salinity, and dissolved oxygen distributions on the Louisiana continental shelf (LCS) near the annual hypoxic zone. Rainfall data from the Tropical Rainfall Measurement Mission (TRMM) were used for the salinity flux, and the diffuse attenuation coefficient (Kd) from Moderate Resolution Imaging Spectroradiometer...
Sun, Deyong; Huan, Yu; Qiu, Zhongfeng; Hu, Chuanmin; Wang, Shengqiang; He, Yijun
Phytoplankton size class (PSC), a measure of different phytoplankton functional and structural groups, is a key parameter to the understanding of many marine ecological and biogeochemical processes. In turbid waters where optical properties may be influenced by terrigenous discharge and nonphytoplankton water constituents, remote estimation of PSC is still a challenging task. Here based on measurements of phytoplankton diagnostic pigments, total chlorophyll a, and spectral reflectance in turbid waters of Bohai Sea and Yellow Sea during summer 2015, a customized model is developed and validated to estimate PSC in the two semienclosed seas. Five diagnostic pigments determined through high-performance liquid chromatography (HPLC) measurements are first used to produce weighting factors to model phytoplankton biomass (using total chlorophyll a as a surrogate) with relatively high accuracies. Then, a common method used to calculate contributions of microphytoplankton, nanophytoplankton, and picophytoplankton to the phytoplankton assemblage (i.e., Fm, Fn, and Fp) is customized using local HPLC and other data. Exponential functions are tuned to model the size-specific chlorophyll a concentrations (Cm, Cn, and Cp for microphytoplankton, nanophytoplankton, and picophytoplankton, respectively) with remote-sensing reflectance (Rrs) and total chlorophyll a as the model inputs. Such a PSC model shows two improvements over previous models: (1) a practical strategy (i.e., model Cp and Cn first, and then derive Cm as C-Cp-Cn) with an optimized spectral band (680 nm) for Rrs as the model input; (2) local parameterization, including a local chlorophyll a algorithm. The performance of the PSC model is validated using in situ data that were not used in the model development. Application of the PSC model to GOCI (Geostationary Ocean Color Imager) data leads to spatial and temporal distribution patterns of phytoplankton size classes (PSCs) that are consistent with results reported from
Crowley, J.K.; Hubbard, B.E.; Mars, J.C.
Remote sensing data from NASA's Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and the first spaceborne imaging spectrometer, Hyperion, show hydrothermally altered rocks mainly composed of natroalunite, kaolinite, cristobalite, and gypsum on both the Mount Shasta and Shastina cones. Field observations indicate that much of the visible altered rock consists of talus material derived from fractured rock zones within and adjacent to dacitic domes and nearby lava flows. Digital elevation data were utilized to distinguish steeply sloping altered bedrock from more gently sloping talus materials. Volume modeling based on the imagery and digital elevation data indicate that Mount Shasta drainage systems contain moderate volumes of altered rock, a result that is consistent with Mount Shasta's Holocene record of mostly small to moderate debris flows. Similar modeling for selected areas at Mount Rainier and Mount Adams, Washington, indicates larger altered rock volumes consistent with the occurrence of much larger Holocene debris flows at those volcanoes. The availability of digital elevation and spectral data from spaceborne sensors, such as Hyperion and the Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER), greatly expands opportunities for studying potential debris flow source characteristics at stratovolcanoes around the world. ?? 2003 Elsevier Inc. All rights reserved.
Full Text Available CO2 is the second most abundant volatile species of degassing magma. CO2 fluxes carry information of incredible value, such as periods of volcanic unrest. Ground-based laser remote sensing is a powerful technique to measure CO2 fluxes in a spatially integrated manner, quickly and from a safe distance, but it needs accurate knowledge of the plume speed. The latter is often difficult to estimate, particularly for complex topographies. So, a supplementary or even alternative way of retrieving fluxes would be beneficial. Here, we assess Bayesian inversion as a potential technique for the case of the volcanic crater of Solfatara (Italy, a complex terrain hosting two major CO2 degassing fumarolic vents close to a steep slope. Direct integration of remotely sensed CO2 concentrations of these vents using plume speed derived from optical flow analysis yielded a flux of 717 ± 121 t day−1, in agreement with independent measurements. The flux from Bayesian inversion based on a simple Gaussian plume model was in excellent agreement under certain conditions. In conclusion, Bayesian inversion is a promising retrieval tool for CO2 fluxes, especially in situations where plume speed estimation methods fail, e.g., optical flow for transparent plumes. The results have implications beyond volcanology, including ground-based remote sensing of greenhouse gases and verification of satellite soundings.
Full Text Available Characterizing vertical distributions of ozone from nadir-viewing satellite measurements is known to be challenging, particularly the ozone information in the troposphere. A novel retrieval algorithm called Full-Physics Inverse Learning Machine (FP-ILM, has been developed at DLR in order to estimate ozone profile shapes based on machine learning techniques. In contrast to traditional inversion methods, the FP-ILM algorithm formulates the profile shape retrieval as a classification problem. Its implementation comprises a training phase to derive an inverse function from synthetic measurements, and an operational phase in which the inverse function is applied to real measurements. This paper extends the ability of the FP-ILM retrieval to derive tropospheric ozone columns from GOME- 2 measurements. Results of total and tropical tropospheric ozone columns are compared with the ones using the official GOME Data Processing (GDP product and the convective-cloud-differential (CCD method, respectively. Furthermore, the FP-ILM framework will be used for the near-real-time processing of the new European Sentinel sensors with their unprecedented spectral and spatial resolution and corresponding large increases in the amount of data.
Xu, J.; Heue, K.-P.; Coldewey-Egbers, M.; Romahn, F.; Doicu, A.; Loyola, D.
Characterizing vertical distributions of ozone from nadir-viewing satellite measurements is known to be challenging, particularly the ozone information in the troposphere. A novel retrieval algorithm called Full-Physics Inverse Learning Machine (FP-ILM), has been developed at DLR in order to estimate ozone profile shapes based on machine learning techniques. In contrast to traditional inversion methods, the FP-ILM algorithm formulates the profile shape retrieval as a classification problem. Its implementation comprises a training phase to derive an inverse function from synthetic measurements, and an operational phase in which the inverse function is applied to real measurements. This paper extends the ability of the FP-ILM retrieval to derive tropospheric ozone columns from GOME- 2 measurements. Results of total and tropical tropospheric ozone columns are compared with the ones using the official GOME Data Processing (GDP) product and the convective-cloud-differential (CCD) method, respectively. Furthermore, the FP-ILM framework will be used for the near-real-time processing of the new European Sentinel sensors with their unprecedented spectral and spatial resolution and corresponding large increases in the amount of data.
Maboudi, Mehdi; Amini, Jalal; Malihi, Shirin; Hahn, Michael
Updated road network as a crucial part of the transportation database plays an important role in various applications. Thus, increasing the automation of the road extraction approaches from remote sensing images has been the subject of extensive research. In this paper, we propose an object based road extraction approach from very high resolution satellite images. Based on the object based image analysis, our approach incorporates various spatial, spectral, and textural objects' descriptors, the capabilities of the fuzzy logic system for handling the uncertainties in road modelling, and the effectiveness and suitability of ant colony algorithm for optimization of network related problems. Four VHR optical satellite images which are acquired by Worldview-2 and IKONOS satellites are used in order to evaluate the proposed approach. Evaluation of the extracted road networks shows that the average completeness, correctness, and quality of the results can reach 89%, 93% and 83% respectively, indicating that the proposed approach is applicable for urban road extraction. We also analyzed the sensitivity of our algorithm to different ant colony optimization parameter values. Comparison of the achieved results with the results of four state-of-the-art algorithms and quantifying the robustness of the fuzzy rule set demonstrate that the proposed approach is both efficient and transferable to other comparable images.
Su, W G; Su, F Z; Zhou, C H
Nowadays, most remote sensing image classification uses single satellite remote sensing data, so the number of bands and band spectral width is consistent. In addition, observed phenomenon such as land cover have the same spectral signature, which causes the classification accuracy to decrease as different data have unique characteristic. Therefore, this paper analyzes different optical remote sensing satellites, comparing the spectral differences and proposes the ideas and methods to build a virtual satellite. This article illustrates the research on the TM, HJ-1 and MODIS data. We obtained the virtual band X 0 through these satellites' bands combined it with the 4 bands of a TM image to build a virtual satellite with five bands. Based on this, we used these data for image classification. The experimental results showed that the virtual satellite classification results of building land and water information were superior to the HJ-1 and TM data respectively
Paris, Adrien; Dias de Paiva, Rodrigo; Santos da Silva, Joecila; Medeiros Moreira, Daniel; Calmant, Stephane; Garambois, Pierre-André; Collischonn, Walter; Bonnet, Marie-Paule; Seyler, Frederique
In this study, rating curves (RCs) were determined by applying satellite altimetry to a poorly gauged basin. This study demonstrates the synergistic application of remote sensing and watershed modeling to capture the dynamics and quantity of flow in the Amazon River Basin, respectively. Three major advancements for estimating basin-scale patterns in river discharge are described. The first advancement is the preservation of the hydrological meanings of the parameters expressed by ...
Full Text Available The main goal of this research was to estimate the actual evapotranspiration (ETc of a drip-irrigated apple orchard located in the semi-arid region of Talca Valley (Chile using a remote sensing-based soil water balance model. The methodology to estimate ETc is a modified version of the Food and Agriculture Organization of the United Nations (FAO dual crop coefficient approach, in which the basal crop coefficient (Kcb was derived from the soil adjusted vegetation index (SAVI calculated from satellite images and incorporated into a daily soil water balance in the root zone. A linear relationship between the Kcb and SAVI was developed for the apple orchard Kcb = 1.82·SAVI − 0.07 (R2 = 0.95. The methodology was applied during two growing seasons (2010–2011 and 2012–2013, and ETc was evaluated using latent heat fluxes (LE from an eddy covariance system. The results indicate that the remote sensing-based soil water balance estimated ETc reasonably well over two growing seasons. The root mean square error (RMSE between the measured and simulated ETc values during 2010–2011 and 2012–2013 were, respectively, 0.78 and 0.74 mm·day−1, which mean a relative error of 25%. The index of agreement (d values were, respectively, 0.73 and 0.90. In addition, the weekly ETc showed better agreement. The proposed methodology could be considered as a useful tool for scheduling irrigation and driving the estimation of water requirements over large areas for apple orchards.
Full Text Available Possibilities of bee forage identification and mapping based on multispectral images Landsat 8 have been shown in the research. The satellite images can be used to determine areas of crops that are resource for nectar and pollen such as sunflower, buckwheat and corn. Identifying bee forages was based on methods of supervised classification such as minimum distance to means, the linear discriminant analysis, the maximum likelihood, the parallelepiped and the k-nearest neighbors. The accuracy of classification methods of remote sensing data for identification of pollen and nectars cultures was compared. The method of maximum likelihood showed the best results for buckwheat and good one for corn and sunflower fields by 13/07/2016. Also this method showed good result for corn and sunflower fields, and poor result for identification of buckwheat fields by 29/07/2016. The stage of flowering plants is the most important period of cropgrowth phase for beekeeping because it is the periodof formation of pollen and nectar. Therefore identification of bee forage has been analyzed vegetation period from germination to flowering. Images of Landsat 8 (sensor OLI by 26/05/2016, 27/06/2016, 13/07/2016 and 29/07/2016 have been used in the research. The optimum period of remote sensing data for identification agricultural crops of bee forage has been determined. Buckwheat fields can be identified more effective in mid-July. Corn fields can be determined at the end of July. Sunflowers can be identified well as before flowering as during flowering.
Katherine J. LaJeunesse Connette
Full Text Available Using freely-available data and open-source software, we developed a remote sensing methodology to identify mining areas and assess recent mining expansion in Myanmar. Our country-wide analysis used Landsat 8 satellite data from a select number of mining areas to create a raster layer of potential mining areas. We used this layer to guide a systematic scan of freely-available fine-resolution imagery, such as Google Earth, in order to digitize likely mining areas. During this process, each mining area was assigned a ranking indicating our certainty in correct identification of the mining land use. Finally, we identified areas of recent mining expansion based on the change in albedo, or brightness, between Landsat images from 2002 and 2015. We identified 90,041 ha of potential mining areas in Myanmar, of which 58% (52,312 ha was assigned high certainty, 29% (26,251 ha medium certainty, and 13% (11,478 ha low certainty. Of the high-certainty mining areas, 62% of bare ground was disturbed (had a large increase in albedo since 2002. This four-month project provides the first publicly-available database of mining areas in Myanmar, and it demonstrates an approach for large-scale assessment of mining extent and expansion based on freely-available data.
Gatkowska, Martyna; Paradowski, Karol; Wróbel, Karolina
The paper aims at demonstrating the assumptions and achievements of the Pilot Utilization Plan Activities performed within the Project ASAP "Advanced Sustainable Agricultural Production", co-financed by European Space Agency under the ARTES IAP Programme. Within the course of the project, the Pilot Utilization Plan (PilUP) activities are performed in order to develop the remote sensing based models, and further calibrate and validate them in order to achieve the accuracy, which meets the requirements of paying customers. The completion of the first PilUP resulted in development of the following models based of Landsat 8 and Sentinel 2 satellite data: model of homogenous polygons demarcation on the basis of comparison of electromagnetic scanning results and bare soil spectral reflectance, model of problematic areas indication and model for yield potential, delivered on the basis of NDVI map developed 1 month before harvest and the map of yield/collected yield derived from Users participating in PilUP. The second edition of the PilUP is being conducted between March 2017 until the end of 2017. This edition includes farmers and insurance companies. The following activities are planned: development of model for delimitation of loses due to unfavorable wintering of winter crops and validation of the model with in-situ data collected by the insurance companies in-field investigators, further enhancement of the model for homogenous polygons delimitation and primary indication of soil productivity and testing of the applicability and viability of map of problematic areas with the farmers.
Elmasri, B.; Rahman, A. F.
Estimating ecosystem carbon fluxes at various spatial and temporal scales is essential for quantifying the global carbon cycle. Numerous models have been developed for this purpose using several environmental variables as well as vegetation indices derived from remotely sensed data. Here we present a data driven modeling approach for gross primary production (GPP) that is based on a process based model BIOME-BGC. The proposed model was run using available remote sensing data and it does not depend on look-up tables. Furthermore, this approach combines the merits of both empirical and process models, and empirical models were used to estimate certain input variables such as light use efficiency (LUE). This was achieved by using remotely sensed data to the mathematical equations that represent biophysical photosynthesis processes in the BIOME-BGC model. Moreover, a new spectral index for estimating maximum photosynthetic activity, maximum photosynthetic rate index (MPRI), is also developed and presented here. This new index is based on the ratio between the near infrared and the green bands (ρ858.5/ρ555). The model was tested and validated against MODIS GPP product and flux measurements from two eddy covariance flux towers located at Morgan Monroe State Forest (MMSF) in Indiana and Harvard Forest in Massachusetts. Satellite data acquired by the Advanced Microwave Scanning Radiometer (AMSR-E) and MODIS were used. The data driven model showed a strong correlation between the predicted and measured GPP at the two eddy covariance flux towers sites. This methodology produced better predictions of GPP than did the MODIS GPP product. Moreover, the proportion of error in the predicted GPP for MMSF and Harvard forest was dominated by unsystematic errors suggesting that the results are unbiased. The analysis indicated that maintenance respiration is one of the main factors that dominate the overall model outcome errors and improvement in maintenance respiration estimation
Zeng, Z.; Zhang, K.; Xue, X.; Hong, Y.
Impervious surface areas around the globe are expanding and significantly altering the surface energy balance, hydrology cycle and ecosystem services. Many studies have underlined the importance of impervious surface, r from hydrological modeling to contaminant transport monitoring and urban development estimation. Therefore accurate estimation of the global impervious surface is important for both physical and social sciences. Given the limited coverage of high spatial resolution imagery and ground survey, using satellite remote sensing and geospatial data to estimate global impervious areas is a practical approach. Based on the previous work of area-weighted imperviousness for north branch of the Chicago River provided by HDR, this study developed a method to determine the percentage of impervious surface using latest global land cover categories from multi-source satellite observations, population density and gross domestic product (GDP) data. Percent impervious surface at 30-meter resolution were mapped. We found that 1.33% of the CONUS (105,814 km2) and 0.475% of the land surface (640,370km2) are impervious surfaces. To test the utility and practicality of the proposed method, National Land Cover Database (NLCD) 2011 percent developed imperviousness for the conterminous United States was used to evaluate our results. The average difference between the derived imperviousness from our method and the NLCD data across CONUS is 1.14%, while difference between our results and the NLCD data are within ±1% over 81.63% of the CONUS. The distribution of global impervious surface map indicates that impervious surfaces are primarily concentrated in China, India, Japan, USA and Europe where are highly populated and/or developed. This study proposes a straightforward way of mapping global imperviousness, which can provide useful information for hydrologic modeling and other applications.
Czernecki, Bartosz; Nowosad, Jakub; Jabłońska, Katarzyna
Changes in the timing of plant phenological phases are important proxies in contemporary climate research. However, most of the commonly used traditional phenological observations do not give any coherent spatial information. While consistent spatial data can be obtained from airborne sensors and preprocessed gridded meteorological data, not many studies robustly benefit from these data sources. Therefore, the main aim of this study is to create and evaluate different statistical models for reconstructing, predicting, and improving quality of phenological phases monitoring with the use of satellite and meteorological products. A quality-controlled dataset of the 13 BBCH plant phenophases in Poland was collected for the period 2007-2014. For each phenophase, statistical models were built using the most commonly applied regression-based machine learning techniques, such as multiple linear regression, lasso, principal component regression, generalized boosted models, and random forest. The quality of the models was estimated using a k-fold cross-validation. The obtained results showed varying potential for coupling meteorological derived indices with remote sensing products in terms of phenological modeling; however, application of both data sources improves models' accuracy from 0.6 to 4.6 day in terms of obtained RMSE. It is shown that a robust prediction of early phenological phases is mostly related to meteorological indices, whereas for autumn phenophases, there is a stronger information signal provided by satellite-derived vegetation metrics. Choosing a specific set of predictors and applying a robust preprocessing procedures is more important for final results than the selection of a particular statistical model. The average RMSE for the best models of all phenophases is 6.3, while the individual RMSE vary seasonally from 3.5 to 10 days. Models give reliable proxy for ground observations with RMSE below 5 days for early spring and late spring phenophases. For
Technical considerations for the Mobile Satellite Experiment (MSAT-X), the ground segment testbed for the low-cost spectral efficient satellite-based mobile communications technologies being developed for the 1990's, are discussed. The Network Management Center contains a flexible resource sharing algorithm, the Demand Assigned Multiple Access scheme, which partitions the satellite transponder bandwidth among voice, data, and request channels. Satellite use of multiple UHF beams permits frequency reuse. The backhaul communications and the Telemetry, Tracking and Control traffic are provided through a single full-coverage SHF beam. Mobile Terminals communicate with the satellite using UHF. All communications including SHF-SHF between Base Stations and/or Gateways, are routed through the satellite. Because MSAT-X is an experimental network, higher level network protocols (which are service-specific) will be developed only to test the operation of the lowest three levels, the physical, data link, and network layers.
A. Beiranvand Pour
Full Text Available The Bentong-Raub Suture Zone (BRSZ of Peninsular Malaysia is one of the significant structural zones in Sundaland, Southeast Asia. It forms the boundary between the Gondwana-derived Sibumasu terrane in the west and Sukhothai arc in the east. The BRSZ is also genetically related to the sediment-hosted/orogenic gold deposits associated with the major lineaments and form-lines in the central gold belt Central Gold Belt of Peninsular Malaysia. In tropical environments, heavy tropical rainforest and intense weathering makes it impossible to map geological structures over long distances. Advances in remote sensing technology allow the application of Synthetic Aperture Radar (SAR data in geological structural analysis for tropical environments. In this investigation, the Phased Array type L-band Synthetic Aperture Radar (PALSAR satellite remote sensing data were used to analyse major geological structures in Peninsular Malaysia and provide detailed characterization of lineaments and form-lines in the BRSZ, as well as its implication for sediment-hosted/orogenic gold exploration in tropical environments. The major geological structure directions of the BRSZ are N-S, NNE-SSW, NE-SW and NW-SE, which derived from directional filtering analysis to PALSAR data. The pervasive array of N-S faults in the study area and surrounding terrain is mainly linked to the N-S trending of the Suture Zone. N-S striking lineaments are often cut by younger NE-SW and NW-SE-trending lineaments. Gold mineralized trends lineaments are associated with the intersection of N-S, NE-SW, NNW-SSE and ESE-WNW faults and curvilinear features in shearing and alteration zones. Lineament analysis on PALSAR satellite remote sensing data is a useful tool for detecting the boundary between the Gondwana-derived terranes and major geological features associated with suture zone especially for large inaccessible regions in tropical environments.
Yang, Yuan-Zheng; Chang, Yu; Hu, Yuan-Man; Liu, Miao; Li, Yue-Hui
To timely and accurately acquire the spatial distribution pattern of wetlands is of significance for the dynamic monitoring, conservation, and sustainable utilization of wetlands. The small remote sensing satellite constellations A/B stars (HJ-1A/1B stars) for environmental hazards were launched by China for monitoring terrestrial resources, which could provide a new data source of remote sensing image acquisition for retrieving wetland types. Taking Liaohe Delta as a case, this paper compared the accuracy of wetland classification map and the area of each wetland type retrieved from CCD data (HJ CCD data) and TM5 data, and validated and explored the applicability and the applied potential of HJ CCD data in wetland resources dynamic monitoring. The results showed that HJ CCD data could completely replace Landsat TM5 data in feature extraction and remote sensing classification. In real-time monitoring, due to its 2 days of data acquisition cycle, HJ CCD data had the priority to Landsat TM5 data (16 days of data acquisition cycle).
Lopez Valencia, Oliver Miguel; Houborg, Rasmus; McCabe, Matthew
observation. Basin-scale studies have shown considerable variability in achieving water budget closure with any degree of accuracy using satellite estimates of the water cycle. In order to assess the suitability of this type of approach for evaluating
McCullum, A. J. K.; Schmidt, C.; Ly, V.; Green, R.; McClellan, C.
The Navajo Nation (NN) is the largest reservation in the US, and faces challenges related to water management during long-term and widespread drought episodes. The Navajo Nation is a federally recognized tribe, which has boundaries within Arizona, New Mexico, and Utah. The Navajo Nation has a land area of over 70,000 square kilometers. The Navajo Nation Department of Water Resources (NNDWR) reports on drought and climatic conditions through the use of regional Standardized Precipitation Index (SPI) values and a network of in-situ rainfall, streamflow, and climate data. However, these data sources lack the spatial detail and consistent measurements needed to provide a coherent understanding of the drought regime within the Nation's regional boundaries. This project, as part of NASA's Western Water Applications Office (WWAO), improves upon the recently developed Drought Severity Assessment Tool (DSAT) to ingest satellite-based precipitation data to generate SPI values for specific administrative boundaries within the reservation. The tool aims to: (1) generate SPI values and summary statistics for regions of interest on various timescales, (2) to visualize SPI values within a web-map application, and (3) produce maps and comparative statistical outputs in the format required for annual drought reporting. The co-development of the DSAT with NN partners is integral to increasing the sustained use of Earth Observations for water management applications. This tool will provide data to support the NN in allocation of drought contingency dollars to the regions most adversely impacted by declines in water availability.
Maqsood, M; Nasir, M Nauman
In the near future due to extensive use of energy, limited supply of resources and the pollution in environment from present resources e.g. (wood, coal, fossil fuel) etc, alternative sources of energy and new ways to generate energy which are efficient, cost effective and produce minimum losses are of great concern. Wireless electricity (Power) transmission (WET) has become a focal point as research point of view and nowadays lies at top 10 future hot burning technologies that are under research these days. In this paper, we present the concept of transmitting power wirelessly to reduce transmission and distribution losses. The wired distribution losses are 70 – 75% efficient. We cannot imagine the world without electric power which is efficient, cost effective and produce minimum losses is of great concern. This paper tells us the benefits of using WET technology specially by using Solar based Power satellites (SBPS) and also focuses that how we make electric system cost effective, optimized and well organized. Moreover, attempts are made to highlight future issues so as to index some emerging solutions.
Minnis, Patrick [NASA Langley Research Center, Hampton, VA
During the period, March 1997 – February 2006, the Principal Investigator and his research team co-authored 47 peer-reviewed papers and presented, at least, 138 papers at conferences, meetings, and workshops that were supported either in whole or in part by this agreement. We developed a state-of-the-art satellite cloud processing system that generates cloud properties over the Atmospheric Radiation (ARM) surface sites and surrounding domains in near-real time and outputs the results on the world wide web in image and digital formats. When the products are quality controlled, they are sent to the ARM archive for further dissemination. These products and raw satellite images can be accessed at http://cloudsgate2.larc.nasa.gov/cgi-bin/site/showdoc?docid=4&cmd=field-experiment-homepage&exp=ARM and are used by many in the ARM science community. The algorithms used in this system to generate cloud properties were validated and improved by the research conducted under this agreement. The team supported, at least, 11 ARM-related or supported field experiments by providing near-real time satellite imagery, cloud products, model results, and interactive analyses for mission planning, execution, and post-experiment scientific analyses. Comparisons of cloud properties derived from satellite, aircraft, and surface measurements were used to evaluate uncertainties in the cloud properties. Multiple-angle satellite retrievals were used to determine the influence of cloud structural and microphysical properties on the exiting radiation field.
Full Text Available Aim to striping noise brought by non-uniform response of remote sensing TDI CCD, a novel de-striping method based on statistical features of image histogram is put forward. By analysing the distribution of histograms,the centroid of histogram is selected to be an eigenvalue representing uniformity of ground objects,histogrammic centroid of whole image and each pixels are calculated first,the differences between them are regard as rough correction coefficients, then in order to avoid the sensitivity caused by single parameter and considering the strong continuity and pertinence of ground objects between two adjacent pixels,correlation coefficient of the histograms is introduces to reflect the similarities between them,fine correction coefficient is obtained by searching around the rough correction coefficient,additionally,in view of the influence of bright cloud on histogram,an automatic cloud detection based on multi-feature including grey level,texture,fractal dimension and edge is used to pre-process image.Two 0-level panchromatic images of SJ-9A satellite with obvious strip noise are processed by proposed method to evaluate the performance, results show that the visual quality of images are improved because the strip noise is entirely removed,we quantitatively analyse the result by calculating the non-uniformity ,which has reached about 1% and is better than histogram matching method.
Full Text Available Abstract Background Malaria is one of the leading public health problems in most of sub-Saharan Africa, particularly in Ethiopia. Almost all demographic groups are at risk of malaria because of seasonal and unstable transmission of the disease. Therefore, there is a need to develop malaria early-warning systems to enhance public health decision making for control and prevention of malaria epidemics. Data from orbiting earth-observing sensors can monitor environmental risk factors that trigger malaria epidemics. Remotely sensed environmental indicators were used to examine the influences of climatic and environmental variability on temporal patterns of malaria cases in the Amhara region of Ethiopia. Methods In this study seasonal autoregressive integrated moving average (SARIMA models were used to quantify the relationship between malaria cases and remotely sensed environmental variables, including rainfall, land-surface temperature (LST, vegetation indices (NDVI and EVI, and actual evapotranspiration (ETa with lags ranging from one to three months. Predictions from the best model with environmental variables were compared to the actual observations from the last 12 months of the time series. Results Malaria cases exhibited positive associations with LST at a lag of one month and positive associations with indicators of moisture (rainfall, EVI and ETa at lags from one to three months. SARIMA models that included these environmental covariates had better fits and more accurate predictions, as evidenced by lower AIC and RMSE values, than models without environmental covariates. Conclusions Malaria risk indicators such as satellite-based rainfall estimates, LST, EVI, and ETa exhibited significant lagged associations with malaria cases in the Amhara region and improved model fit and prediction accuracy. These variables can be monitored frequently and extensively across large geographic areas using data from earth-observing sensors to support public
Fowler, Laura D.; Wielicki, Bruce A.; Randall, David A.; Branson, Mark D.; Gibson, Gary G.; Denn, Fredrick M.
Collocated in time and space, top-of-the-atmosphere measurements of the Earth radiation budget (ERB) and cloudiness from passive scanning radiometers, and lidar- and radar-in-space measurements of multilayered cloud systems, are the required combination to improve our understanding of the role of clouds and radiation in climate. Experiments to fly multiple satellites "in formation" to measure simultaneously the radiative and optical properties of overlapping cloud systems are being designed. Because satellites carrying ERB experiments and satellites carrying lidars- or radars-in space have different orbital characteristics, the number of simultaneous measurements of radiation and clouds is reduced relative to the number of measurements made by each satellite independently. Monthly averaged coincident observations of radiation and cloudiness are biased when compared against more frequently sampled observations due, in particular, to the undersampling of their diurnal cycle, Using the Colorado State University General Circulation Model (CSU GCM), the goal of this study is to measure the impact of using simultaneous observations from the Earth Observing System (EOS) platform and companion satellites flying lidars or radars on monthly averaged diagnostics of longwave radiation, cloudiness, and its cloud optical properties. To do so, the hourly varying geographical distributions of coincident locations between the afternoon EOS (EOS-PM) orbit and the orbit of the ICESAT satellite set to fly at the altitude of 600 km, and between the EOS PM orbit and the orbits of the PICASSO satellite proposed to fly at the altitudes of 485 km (PICA485) or 705 km (PICA705), are simulated in the CSU GCM for a 60-month time period starting at the idealistic July 1, 2001, launch date. Monthly averaged diagnostics of the top-of-the-atmosphere, atmospheric, and surface longwave radiation budgets and clouds accumulated over grid boxes corresponding to satellite overpasses are compared against
Onega, Tracy; Alford-Teaster, Jennifer; Wang, Fahui
Satellite facilities of National Cancer Institute (NCI) cancer centers have expanded their regional footprints. This study characterized geographic access to parent and satellite NCI cancer center facilities nationally overall and by sociodemographics. Parent and satellite NCI cancer center facilities, which were geocoded in ArcGIS, were ascertained. Travel times from every census tract in the continental United States and Hawaii to the nearest parent and satellite facilities were calculated. Census-based population attributes were used to characterize measures of geographic access for sociodemographic groups. From the 62 NCI cancer centers providing clinical care in 2014, 76 unique parent locations and 211 satellite locations were mapped. The overall proportion of the population within 60 minutes of a facility was 22% for parent facilities and 32.7% for satellite facilities. When satellites were included for potential access, the proportion of some racial groups for which a satellite was the closest NCI cancer center facility increased notably (Native Americans, 22.6% with parent facilities and 39.7% with satellite facilities; whites, 34.8% with parent facilities and 50.3% with satellite facilities; and Asians, 40.0% with parent facilities and 54.0% with satellite facilities), with less marked increases for Hispanic and black populations. Rural populations of all categories had dramatically low proportions living within 60 minutes of an NCI cancer center facility of any type (1.0%-6.6%). Approximately 14% of the population (n = 43,033,310) lived more than 180 minutes from a parent or satellite facility, and most of these individuals were Native Americans and/or rural residents (37% of Native Americans and 41.7% of isolated rural residents). Racial/ethnic and rural populations showed markedly improved geographic access to NCI cancer center care when satellite facilities were included. Cancer 2017;123:3305-11. © 2017 American Cancer Society. © 2017 American
Chen, Weiyi; Deng, Pingke; Qu, Yi; Zhang, Xiaoguang; Li, Yaping
Satellite navigation system plays an important role in people's daily life and war. The strategic position of satellite navigation system is prominent, so it is very important to ensure that the satellite navigation system is not disturbed or destroyed. It is a critical means to detect the jamming signal to avoid the accident in a navigation system. At present, the detection technology of jamming signal in satellite navigation system is not intelligent , mainly relying on artificial decision and experience. For this issue, the paper proposes a method based on deep learning to monitor the interference source in a satellite navigation. By training the interference signal data, and extracting the features of the interference signal, the detection sys tem model is constructed. The simulation results show that, the detection accuracy of our detection system can reach nearly 70%. The method in our paper provides a new idea for the research on intelligent detection of interference and deception signal in a satellite navigation system.
Roberts, D R; Paris, J F; Manguin, S; Harbach, R E; Woodruff, R; Rejmankova, E; Polanco, J; Wullschleger, B; Legters, L J
Use of multispectral satellite data to predict arthropod-borne disease trouble spots is dependent on clear understandings of environmental factors that determine the presence of disease vectors. A blind test of remote sensing-based predictions for the spatial distribution of a malaria vector, Anopheles pseudopunctipennis, was conducted as a follow-up to two years of studies on vector-environmental relationships in Belize. Four of eight sites that were predicted to be high probability locations for presence of An. pseudopunctipennis were positive and all low probability sites (0 of 12) were negative. The absence of An. pseudopunctipennis at four high probability locations probably reflects the low densities that seem to characterize field populations of this species, i.e., the population densities were below the threshold of our sampling effort. Another important malaria vector, An. darlingi, was also present at all high probability sites and absent at all low probability sites. Anopheles darlingi, like An. pseudopunctipennis, is a riverine species. Prior to these collections at ecologically defined locations, this species was last detected in Belize in 1946.
Hnatushenko, Volodymyr; Garkusha, Igor; Vasyliev, Volodymyr
The presented work is related to a study of mapping soil moisture basing on radar data from Sentinel-1 and a test of adequacy of the models constructed on the basis of data obtained from alternative sources. Radar signals are reflected from the ground differently, depending on its properties. In radar images obtained, for example, in the C band of the electromagnetic spectrum, soils saturated with moisture usually appear in dark tones. Although, at first glance, the problem of constructing moisture maps basing on radar data seems intuitively clear, its implementation on the basis of the Sentinel-1 data on an industrial scale and in the public domain is not yet available. In the process of mapping, for verification of the results, measurements of soil moisture obtained from logs of the network of climate stations NOAA US Climate Reference Network (USCRN) were used. This network covers almost the entire territory of the United States. The passive microwave radiometers of Aqua and SMAP satellites data are used for comparing processing. In addition, other supplementary cartographic materials were used, such as maps of soil types and ready moisture maps. The paper presents a comparison of the effect of the use of certain methods of roughening the quality of radar data on the result of mapping moisture. Regression models were constructed showing dependence of backscatter coefficient values Sigma0 for calibrated radar data of different spatial resolution obtained at different times on soil moisture values. The obtained soil moisture maps of the territories of research, as well as the conceptual solutions about automation of operations of constructing such digital maps, are presented. The comparative assessment of the time required for processing a given set of radar scenes with the developed tools and with the ESA SNAP product was carried out.
Doyle, Martin; Dorling, Stephen
Plumes of atmospheric aerosol have been studied using a range of satellite and ground-based techniques. The Sea-viewing WideField-of-view Sensor (SeaWiFS) has been used to observe plumes of sulphate aerosol and Saharan dust around the coast of the United Kingdom. Aerosol Optical Thickness (AOT) was retrieved from SeaWiFS for two events; a plume of Saharan dust transported over the United Kingdom from Western Africa and a period of elevated sulphate experienced over the Easternregion of the UK. Patterns of AOT are discussed and related to the synoptic and mesoscale weather conditions. Further observation of the sulphate aerosol event was undertaken using the Advanced Very High Resolution Radiometer instrument(AVHRR). Atmospheric back trajectories and weather conditions were studied in order to identify the meteorological conditions which led to this event. Co-located ground-based measurements of PM 10 and PM 2.5 were obtained for 4sites within the UK and PM 2.5/10 ratios were calculated in order to identify any unusually high or low ratios(indicating the dominant size fraction within the plume)during either of these events. Calculated percentiles ofPM 2.5/10 ratios during the 2 events examined show that these events were notable within the record, but were in noway unique or unusual in the context of a 3 yr monitoring record. Visibility measurements for both episodes have been examined and show that visibility degradation occurred during both the sulphate aerosol and Saharan dust episodes
Full Text Available This study designs a real-time remote monitoring system based on LabVIEW and Microsoft Visual C++ for Plant Units. The server written in LabVIEW uses for data acquisition and storage. The server adopts the TCP and DataSocket to communicate with the VC client. The remote VC client can accept real-time data and process data, enabling remote monitoring.
Xiong Delan; Du Genyuan
Aiming at the questions of vast data, complex operation, and time consuming processing for remote sensing image, subdivision template was proposed based on global subdivision theory, which can set up high level of abstraction and generalization for remote sensing image. The paper emphatically discussed the model and structure of subdivision template, and put forward some new ideas for remote sensing image template processing, key technology and quickly applied demonstration. The research has ...
Aug 31, 2017 ... to comprehend the tectonic development of the ... software for the analysis and interpretation of G– .... The application of remote sensing for mapping ..... Pf1 and Pf2 show profile locations adopted for joint G–M modelling.
Belogub, V.P.; Kal'schikov, I.B.; Kirillov, Yu.K.; Kulikov, V.N.; Shumov, A.N.
One of the most important indicators of successful function of the International Monitoring System is existence of highly reliable communication channels providing transfer data from observation points in a real time scales. Up to present, the most communication channels were provided with existing VF-channels (Voice Frequency) that are relatively low-speedy in transfer process (4.8-9.6 kbit/sec.). In addition, reliability of the channels is insufficient because of many retransmission points. In connection with it, the special control service of MD RF decided to improve the information transfer system (ITS) installed between the observation point and National Data Center (Dubna-city). The improvement of the ITS comprises replacement of wire lines of VF-channels with satellite ones within the framework of the computer-aided satellite communication system (CASCS) M aterik . Besides it was considered to be expedient that the satellite system of data transfer from NPP to the Crisis Center of 'ROSENERGOATOM' Concern would be combined with CASCS M aterik , using the facilities of the Central Earth Station of Satellite Communication (CESSC) in Dubna. Such approach to the creation of Satellite communication has advantages in solution of radiation safety and global monitoring issues
Zhang Bin; Liu Zixin
This paper introduces the function and principle of the remote intelligent terminal. It was designed on SmartARM 2200, uses uC/OS-II operating system and MiniGUI. And then,it gives a method to realize it. Introduces the work flow of remote intelligent terminal, and the function module of the system are analyzed in detail, and then the terminal of the principle has carried on the preliminary study. (authors)
Full Text Available As a result of increasing attention paid to aerosols in climate studies, numerous global satellite aerosol products have been generated. Aerosol parameters and underlining physical processes are now incorporated in many general circulation models (GCMs in order to account for their direct and indirect effects on the earth's climate, through their interactions with the energy and water cycles. There exists, however, an outstanding problem that these satellite products have substantial discrepancies, that must be lowered substantially for narrowing the range of the estimates of aerosol's climate effects. In this paper, numerous key uncertain factors in the retrieval of aerosol optical depth (AOD are articulated for some widely used and relatively long satellite aerosol products including the AVHRR, TOMS, MODIS, MISR, and SeaWiFS. We systematically review the algorithms developed for these sensors in terms of four key elements that influence the quality of passive satellite aerosol retrieval: calibration, cloud screening, classification of aerosol types, and surface effects. To gain further insights into these uncertain factors, the NOAA AVHRR data are employed to conduct various tests, which help estimate the ranges of uncertainties incurred by each of the factors. At the end, recommendations are made to cope with these issues and to produce a consistent and unified aerosol database of high quality for both environment monitoring and climate studies.
Alder-Golden, Steven M.; Rochford, Peter; Matthew, Michael; Berk, Alexander
Software has been developed for an improved method of correcting for the atmospheric optical effects (primarily, effects of aerosols and water vapor) in spectral images of the surface of the Earth acquired by airborne and spaceborne remote-sensing instruments. In this method, the variables needed for the corrections are extracted from the readings of a radiometer located on the ground in the vicinity of the scene of interest. The software includes algorithms that analyze measurement data acquired from a shadow-band radiometer. These algorithms are based on a prior radiation transport software model, called MODTRAN, that has been developed through several versions up to what are now known as MODTRAN4 and MODTRAN5 . These components have been integrated with a user-friendly Interactive Data Language (IDL) front end and an advanced version of MODTRAN4. Software tools for handling general data formats, performing a Langley-type calibration, and generating an output file of retrieved atmospheric parameters for use in another atmospheric-correction computer program known as FLAASH have also been incorporated into the present soft-ware. Concomitantly with the soft-ware described thus far, there has been developed a version of FLAASH that utilizes the retrieved atmospheric parameters to process spectral image data.
Soheili, Mahmoud; (Tom) Rientjes, T. H. M.; (Christiaan) van der Tol, C.
Groundwater movement is influenced by several factors and processes in the hydrological cycle, from which, recharge is of high relevance. Since the amount of aquifer extractable water directly relates to the recharge amount, estimation of recharge is a perquisite of groundwater resources management. Recharge is highly affected by water loss mechanisms the major of which is actual evapotranspiration (ETa). It is, therefore, essential to have detailed assessment of ETa impact on groundwater recharge. The objective of this study was to evaluate how recharge was affected when satellite-based evapotranspiration was used instead of in-situ based ETa in the Salland area, the Netherlands. The Methodology for Interactive Planning for Water Management (MIPWA) model setup which includes a groundwater model for the northern part of the Netherlands was used for recharge estimation. The Surface Energy Balance Algorithm for Land (SEBAL) based actual evapotranspiration maps from Waterschap Groot Salland were also used. Comparison of SEBAL based ETa estimates with in-situ abased estimates in the Netherlands showed that these SEBAL estimates were not reliable. As such results could not serve for calibrating root zone parameters in the CAPSIM model. The an | <urn:uuid:0958e5c2-2836-4769-a1f6-3beb9b7f1df7> | 3.15625 | 126,533 | Content Listing | Science & Tech. | 22.137979 | 95,531,890 |
Using a new measurement technique, Heidelberg researchers have succeeded in tracking interactions between proteins and DNA in the cell nucleus at a resolution of 1/1000 of a second.
Microscopy images after bleaching the fluorescence in a circular or rectangular region. The dark “shadows” represent the bleached proteins that moved as the image was being recorded.
Picture credits: Fabian Erdel and Karsten Rippe
They were able to measure the binding of highly specialised protein complexes that specifically change the spatial structure of the genetic information, thereby controlling the readout of the DNA information. The work of Dr. Karsten Rippe and his team was carried out at the BioQuant Center of Heidelberg University and the German Cancer Research Center.
Their research has demonstrated that the positioning of nucleosomes – complexes of DNA and specialised proteins – is a precisely regulated molecular process. Aberrant regulation can be linked to several types of cancer. The results of these studies were published in the journal PNAS.
In the human genome, the DNA strands are wrapped around specific packaging proteins, the histones. Located between these complexes, called nucleosomes, are histone-free DNA sequences that connect the nucleosomes, much like a pearl necklace. “Activating a gene requires freely accessible DNA. If the corresponding DNA is occluded in the nucleosome, the gene is often turned off”, explains Dr. Rippe.“Hence, the nucleosome positions determine the readout pattern of the DNA sequence. The free DNA between two nucleosomes is more easily accessible than the DNA sequences in a nucleosome.” Molecular machines called chromatin remodelers can use energy to move nucleosomes along the DNA chain. Thus they establish the readout pattern that, along with other factors, determines the active DNA programme of the cell.
World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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The Leggett–Garg inequality, named for Anthony James Leggett and Anupam Garg, is a mathematical inequality fulfilled by all macrorealistic physical theories. Here, macrorealism (macroscopic realism) is a classical worldview defined by the conjunction of two postulates:
- Macrorealism per se: "A macroscopic object, which has available to it two or more macroscopically distinct states, is at any given time in a definite one of those states."
- Noninvasive measurability: "It is possible in principle to determine which of these states the system is in without any effect on the state itself, or on the subsequent system dynamics."
In quantum mechanics
In quantum mechanics, the Leggett–Garg inequality is violated, meaning that the time evolution of a system cannot be understood classically. The situation is similar to the violation of Bell's inequalities in Bell test experiments which plays an important role in understanding the nature of the Einstein–Podolsky–Rosen paradox. Here quantum entanglement plays the central role. The violation of Bell's inequalities rules out local hidden variable theories which attempt to restore the realism in the sense that definiteness of the outcome in a single measurement can be ensured by using a supplementary variable along with the wave function which can not be obtained in the standard Copenhagen Interpretation of quantum mechanics in its various formulations.
As well as Einstein's famous "God does not play dice" objection to quantum mechanics, there was Einstein's still more fundamental objection that the Moon is still there when nobody looks. If the violation of the Leggett–Garg inequality can be demonstrated on the macroscopic scale, this would challenge even this notion of realism.
The simplest form of the Leggett–Garg inequality derives from examining a system that has only two possible states. These states have corresponding measurement values . The key here is that we have measurements at two different times, and one or more times between the first and last measurement. The simplest example is where the system is measured at three successive times . Now suppose, for instance, that there is a perfect correlation of 1 between times and . That is to say, that for N realisations of the experiment, the temporal correlation reads
We look at this case in some detail. What can be said about what happens at time ? Well, it is possible that , so that if the value at , then it is also for both times and . It is also quite possible that , so that the value at is flipped twice, and so has the same value at as it did at . So, we can have both and anti-correlated as long as we have and anti-correlated. Yet another possibility is that there is no correlation between and . That is we could have . So, although it is known that if at it must also be at , the value at may as well be determined by the toss of a coin. We define as . In these three cases, we have and , respectively.
All that was for 100% correlation between times and . In fact, for any correlation between these times . To see this, we note that
It is easily seen that for every realisation , the term in the parentheses must be less than or equal to unity, so that the result for the sum is also less than (or equal to) unity. If we have four distinct times rather than three, we have and so on. These are the Leggett–Garg inequalities. They say something definite about the relation between the temporal correlations of and the correlations between successive times in going from the start to the end.
In the derivations above, it has been assumed that the quantity Q, representing the state of the system, always has a definite value (macrorealism per se) and that its measurement at a certain time does not change this value nor its subsequent evolution (noninvasive measurability). A violation of the Leggett–Garg inequality implies that at least one of these two assumptions fails.
One of the first proposed experiments for demonstrating a violation of macroscopic realism employs superconducting quantum interference devices. There, using Josephson junctions, one should be able to prepare macroscopic superpositions of left and right rotating macroscopically large electronic currents in a superconducting ring. Under sufficient suppression of decoherence one should be able to demonstrate a violation of the Leggett–Garg inequality. However, some criticism has been raised concerning the nature of indistinguishable electrons in a Fermi sea.
A criticism of some other proposed experiments on the Leggett–Garg inequality is that they do not really show a violation of macrorealism because they are essentially about measuring spins of individual particles. In 2015 Robens et al. demonstrated an experimental violation of the Leggett–Garg inequality using superpositions of positions instead of spin with a massive particle. At that time, and so far up until today, the Cesium atoms employed in their experiment represent the largest quantum objects which have been used to experimentally test the Leggett–Garg inequality.
The experiments of Robens et al. as well as Knee et al., using ideal negative measurements, also avoid a second criticism (referred to as “clumsiness loophole” ) that has been directed to previous experiments using measurement protocols that could be interpreted as invasive, thereby conflicting with postulate 2.
Brukner and Kofler have also demonstrated that quantum violations can be found for arbitrarily large macroscopic systems. As an alternative to quantum decoherence, Brukner and Kofler are proposing a solution of the quantum-to-classical transition in terms of coarse-grained quantum measurements under which usually no violation of the Leggett–Garg inequality can be seen anymore.
Experiments proposed by Mermin and Braunstein and Mann would be better for testing macroscopic realism, but warns that the experiments may be complex enough to admit unforeseen loopholes in the analysis. A detailed discussion of the subject can be found in the review by Emary et al.
- Quantum Mechanics versus macroscopic realism: is the flux there when nobody looks? A. J. Leggett and Anupam Garg. Phys. Rev. Lett. 54, 857 (1985)
- Testing the limits of quantum mechanics: motivation, state of play, prospects. A. J. Leggett. J. Phys.: Condens. Matter 14, R414-R451 (2002)
- Electronic structure of superposition states in flux qubits. J. I. Korsbakken, F. K. Wilhelm, and K. B. Whaley, Physica Scripta 137, 4022 (2009). https://link.springer.com/article/10.1007%2Fs10701-011-9598-4
- Superconducting qubit in a resonator: test of the Leggett-Garg inequality and single-shot readout, A. Palacios-Laloy, PhD thesis (2010). http://iramis.cea.fr/spec/Pres/Quantro/static/wp-content/uploads/2010/10/Palacios-Laloy-Thesis1.pdf
- Foundations and Interpretation of Quantum Mechanics. Gennaro Auletta and Giorgio Parisi, World Scientific, 2001 ISBN 981-02-4614-5, ISBN 978-981-02-4614-3
- "Ideal Negative Measurements in Quantum Walks Disprove Theories Based on Classical Trajectories". Carsten Robens, Wolfgang Alt, Dieter Meschede, Clive Emary, and Andrea Alberti, Physical Review X 5, 011003 (2015).
- "Do Quantum Superpositions Have a Size Limit?" , George C. Knee, Physics 8, 6 (2015).
- "Violation of a Leggett–Garg inequality with ideal non-invasive measurements" , George C. Knee, Stephanie Simmons, Erik M. Gauger, John J.L. Morton, Helge Riemann, Nikolai V. Abrosimov, Peter Becker, Hans-Joachim Pohl, Kohei M. Itoh, Mike L.W. Thewalt, G. Andrew D. Briggs & Simon C. Benjamin, Nature Communications 3 606 (2012).
- "Addressing the Clumsiness Loophole in a Leggett-Garg Test of Macrorealism". Mark M. Wilde and Ari Mizel, Foundations of Physics 42, 256 (2012).
- "Violation of the Leggett-Garg Inequality in Neutrino Oscillations". J. A. Formaggio, D. I. Kaiser, M. M. Murskyj, and T. E. Weiss, Physical Review Letters 117, 050402 (2016).
- Classical world arising out of quantum physics under the restriction of coarse-grained measurements. Johannes Kofler and Caslav Brukner. Phys. Rev. Lett. 99, 180403 (2007), ArXiv 0609079 [quant-ph] Sept. 2006 https://arxiv.org/abs/quant-ph/0609079
- The conditions for quantum violation of macroscopic realism. Johannes Kofler and Caslav Brukner. Phys. Rev. Lett. 101, 090403 (2008), ArXiv 0706.0668 [quant-ph] June 2007 https://arxiv.org/abs/0706.0668
- Extreme quantum entanglement in a superpostion of macroscopically distinct states. David Mermin, Phys. Rev. Lett. 65 1838-1840 (1990)
- Noise in Mermin's n-particle Bell inequality. Braunstein, S.L. and Mann, A., Phys. Rev. A 47, R2427-R2430 (1993)
- Leggett–Garg inequalities. C. Emary, N. Lambert, and F. Nori, Rep. Prog. Phys. 77, 016001 (2014). https://arxiv.org/abs/1304.5133
- Bell type equalities for SQUIDs on the assumptions of macroscopic realism and non-invasive measurability. Gregg Jaeger, Chris Viger and Sahotra Sarkar. Phys. Lett. A 210, 5-10 (1996) | <urn:uuid:0678ae3e-4c3f-43d6-a0ed-462e163fb8f4> | 3.3125 | 2,208 | Knowledge Article | Science & Tech. | 52.051099 | 95,531,902 |
Breakdown of Streamwise Vortices near a Wall
Counter-rotating streamwise vortices within a laminar boundary layer were produced by a Görtler instability mechanism on a concave wall. Contour maps of constant streamwise velocity in the y–z plane normal to the mean flow revealed that the vortices produce strong distortions in the mean flow. Fluid was removed from the wall outward and produced regions where low speed fluid lay over higher momentum fluid. This highly unstable situation produced strongly inflectional profiles in both the normal and spanwise directions. Contour maps of the fluctuations suggest that the velocity oscillations are more closely related to the gradients in the spanwise direction rather than to the normal velocity gradient. The fluctuations broke down into turbulence at a Görtler number of approximately 9.
KeywordsStreamwise Velocity Laminar Boundary Layer Spanwise Direction Streamwise Vortex Eddy Structure
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- 6.Blackwelder, R.F.: (1983) Accepted by Phys. of Fluids.Google Scholar
- 7.Tani, I. and Sakagami, J.: Proc. International Council of the Aeronautical Sciences (1964) 391. Spartan Books, Inc., Washington D.C.Google Scholar
- 8.Corke, T.C.; Guezennec, Y. and Nagib, H.M.: Viscous Flow Drag Reduction, ed. G.R. Hough. Progress in Aeronautics and Astronautics 72 (1980) 128.Google Scholar
- 10.Blackwelder, R.F. and Haritonidis, J.H.: 1983, accepted by J. Fluid Mech.Google Scholar
- 11.Liepmann, H.W.: “Investigation of Boundary Layer Transition on Concave Walls”, NACA Wartime Report W87 (1945).Google Scholar | <urn:uuid:051881ad-47d6-430a-891d-5acd7c6e48b3> | 2.5625 | 401 | Academic Writing | Science & Tech. | 56.368595 | 95,531,904 |
UC Riverside biologists show death has no impact on strength geckos use to adhere to surfaces
Geckos, found in places with warm climates, have fascinated people for hundreds of years. Scientists have been especially intrigued by these lizards, and have studied a variety of features such as the adhesive toe pads on the underside of gecko feet with which geckos attach to surfaces with remarkable strength.
Photo shows the underside of the gecko's foot. Underneath the toes are 'setae,' millions of very fine hair-like structures, which provide increased surface area and close contact between the foot and the surface on which it rests. The setae are curved inward, toward the center of the foot. When the gecko pulls back a toe, the setae get straightened.
Credit: Emily Kane
One unanswered question that has captivated researchers is: Is the strength of this adhesion determined by the gecko or is it somehow intrinsic to the adhesive system? In other words, is this adhesion a result of the entire animal initiating it? Or is the adhesion fundamentally "passive," its strength resulting from the way just the toe pads work?
Biologists at the University of California, Riverside have now conducted experiments in the lab on live and dead geckos to determine the answer. Their experiments show, for the first time, that dead geckos can adhere with the exact same strength as living geckos.
Study results, appearing online Dec. 3 in Biology Letters, could have applications in the field of robotics.
"With regards to geckos, being sticky doesn't require effort," said Timothy E. Higham, an assistant professor of biology, who conducted the research alongside William J. Stewart, a postdoctoral researcher inhis lab. "We found that dead geckos maintain the ability to adhere with the same force as living animals, eliminating the idea that strong adhesion requires active control. Death affects neither the motion nor the posture of clinging gecko feet. We found no difference in the adhesive force or the motion of clinging digits between our before- and after-death experiments."
Higham explained that there have been suggestions in the literature for many years that gecko adhesion at the organismal, or whole-animal, level (where the intact animal initiates adhesion) requires an active component such as muscle activity to push the foot and toes onto the surface in order to enhance adhesion. This has, however, never been tested.
Higham and Stewart took on the challenge and tested the hypothesis. The researchers used a novel device involving a controlled pulling system. This device applies repeatable and steady-increasing pulling forces to the gecko foot in shear. Specifically, the device measures clings by pulling a gecko foot in a highly controlled manner along a vertical acrylic sheet while simultaneously recording shear adhesion with video cameras.
The experiments showed that the adhesive force or motion of a gecko foot when pulled along a vertical surface was similarly high and variable when the gecko was alive and immediately - within 30 minutes - after death.
Geckos can climb a variety of surfaces, including smooth glass. Their sticky toes have inspired climbing devices such as Spider-Man gloves. The toe pads on the underside of gecko feet contain tiny hair-like structures called setae. The setae adhere to contacted surfaces through frictional forces as well as forces between molecules, called van der Waals forces. These tiny structures are so strong that the setae on a single foot can support 20 times the gecko's body weight.
The controlled experiments the researchers performed are the first to show that dead animals maintain the ability to adhere with the same force as living animals. The results refute the notion that actions by a living gecko, such as muscle recruitment or neural activity, are required for gecko feet to generate forces.
"The idea that adhesion can be entirely passive could apply to many different kinds of adhesion," Higham said. "This is clearly a cost-effective way of remaining stationary in a habitat. For example, geckos could perch on a smooth vertical surface and sleep for the night - or day - without using any energy."
The new work suggests that the "active" component of gecko adhesion is actually a reduction of adhesion force when the gecko "hyperextends" its digits - that is, lifts them off the ground by curling up only the tips of the digits while the rest of the foot remains on the surface.
"We found that the dead animals were more likely to experience damage to their adhesive system, which suggests that the active control may actually prevent injury," Stewart aid. "In other words, when the forces become too high, the gecko likely releases the system using its muscles."
The research was supported by a grant to Higham from the National Science Foundation. Stewart, the first author of the research paper, is now a postdoctoral scholar at the Whitney Laboratory for Marine Bioscience, the University of Florida.
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.
Iqbal Pittalwala | EurekAlert!
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
Pollen taxi for bacteria
18.07.2018 | Technische Universität München
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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This paper outlines molecular analyses of soil fungi within the Bonanza Creek Long Term Ecological Research program. We examined community structure in three studies in mixed upland, black spruce (Picea mariana (Mill.) BSP), and white spruce (Picea glauca (Moench) Voss) forests and examined taxa involved in cellulose degradation at one upland site. We found that soil horizon was the factor by which fungal communities were most strongly structured and that predictable turnover in upland fungal species occurred through succession. Communities from consecutive summers were not significantly different, indicating that interannual variation was small in relation to differences between forest types and soil horizons, yet the community at a seasonal study site underwent significant changes within a year. In each study, mycorrhizal fungi dominated the community. Fungi rather than bacteria appeared to dominate C-13 cellulose degradation, with strongest growth in taxa that were not dominant members of the untreated community, including members of the genus Sebacina. Overall, our results point to considerable interannual resilience juxtaposed with narrow niche partitioning and the capacity of individual taxa in these hyperdiverse communities to respond strongly to resource inputs and changes in other abiotic environmental parameters such as temperature. Our data double the cumulative total of fungal sequences in GenBank and together achieve a better picture of fungal communities here than for any other ecosystem on earth at this time.
Mendeley saves you time finding and organizing research
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Defining Vectors for Various Crystal Systems
There are several definitions for the basis vectors for face-centered cubic (FCC) structures and lattices. The most common uses the nonprimitive cube with axes A, B, C as shown in Figure 2.1. Conceptually, this set is the easiest to grasp, but the primitive set is essential for finding the allowed reflections.
KeywordsBasis Vector Transformation Equation Plane Index Primitive Vector Primitive Unit Cell
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A lithophysa is a spherulitic bubble or cavity found in felsic volcanic rocks and glassy basalts and certain rhyolites. It is believed to be caused by expanding gases in tuffs before solidification. If it has become lined with crystals it may be referred to as a geode or a thunderegg. The word lithophysa is from the Latin for rock bubble. The term vug is also used for similar cavities although vug is usually restricted to mean cavities in rocks formed by the removal of material such as soluble minerals. | <urn:uuid:726812fa-1808-40e5-bf38-732d56c52484> | 3.09375 | 117 | Knowledge Article | Science & Tech. | 41.430921 | 95,531,922 |
|NDT.net - September 2002, Vol. 7 No.09|
There are numerous ways to apply AE techniques. Many reports of its successful application come from laboratory investigations of the behavior of various kinds of materials (e.g. steel, polymers, wood, concrete, fiber reinforced materials, etc.) or of real structures in the field, such as pressure vessels. After some distrust of this method in the early 1980's due to doubtful measurements of vessels, AE is nowadays becoming more and more "popular" and is successfully applied to numerous measurement problems.
Some reasons for its increasing acceptance and use are the advancements in microelectronics and in computer-based analysis techniques. AE is usually dealing with high signal rates and events at relatively high frequencies (from 20 kHz up to several megahertz). Recording and analysis devices need powerful techniques to handle these data.
Another point motivating the development of AE techniques was the interconnection between AE and seismology. The close relationship of these two disciplines inspired scientists to transfer measurement and analysis techniques from earthquake engineering to acoustic emission applications in the 1980's. It is remarkable that even sophisticated techniques such as the three dimensional localization of events, the moment tensor inversion or wavelet techniques are nowadays routinely applied in the AE environment and it is expected that other methods will stimulate further developments.
New developments raise new problems, however, therefore the demands on the equipment are still very high. This is particularly true concerning the sensor technology. Resonant transducers are increasingly replaced by sensors with broader frequency characteristics. Issues of flat response, sensitivity and calibration have to be addressed more carefully in the future. Other sensor techniques that are currently discussed in the field of AE applications (e.g. in structural health monitoring) use network techniques, wireless communication and Micro-Electro-Mechanical Systems (MEMS). These promising ideas ensure that the acoustic emission technology will be a field of interesting future developments and applications.
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This is a simple Java Oriented language program. If you are newbie in Java programming then our tutorial and example are helpful for understanding Java programming in the simplest way. Here we will learn how to swap or exchange the number to each other. First of all we have to create a class "Swap". Now, we use the Integer.parseInt(args[o]) and Integer.parseInt(args) methods for getting the integer type values in command line. Use a temporary variable z of type integer that will help us to swap the numbers Assign the value of x to z variable, now assign the value of y to the variable x. Lastly assign the value of z to variable y. Now we get the values has been interchanged. To display the values on the command prompt use println() method and the swapped values will be displayed.
Here is the code of this program | <urn:uuid:7a06d013-11f0-43a6-92ab-2d6be2179d76> | 3.453125 | 180 | Tutorial | Software Dev. | 63.68323 | 95,531,960 |
Far from shore, the ocean floor is more than an unbroken swath of sand and mud: It can be blanketed with lush, green carpets of seagrass. These wavy expanses are biodiversity hotspots and have significant ecological benefits, but because so little of the ocean has been surveyed and mapped, scientists don’t know exactly where all of these green spaces are. “We know more about the surface of Mars than the ocean floor,” said American Museum of Natural History ichthyologist John Sparks at a recent event at the museum.
There’s a general consensus that these undersea meadows are numerous and widely dispersed in shallow and deeper water alike, since seagrasses can survive on fewer nutrients than some other plants can manage. But grasses growing far beneath the waves often go unstudied compared to those closer to shore. Since green turtles (Chelonia mydas) are known to nibble on seagrasses, researchers at Swansea University trailed them, with the idea that they might lead the way to their sunken grazing grounds.
The scientists tagged turtles with GPS devices when the reptiles clustered to nest on shore, 18 in total. Satellite tracking then helped the researchers follow them—eventually to the Great Chagos Bank, a vast atoll in the Western Indian Ocean. With information about location and depth in hand, divers went to check out where the turtles were headed.
In this remote tract of ocean, the scientists found previously unknown meadows of a seagrass known as Thalassodendron ciliatum. Writing in Marine Pollution Bulletin, the researchers describe the abundance of marine life they encountered there—nearly a dozen fish species, including a large shark.
Seagrass is a natural carbon sink, locking it up like terrestrial trees and a host of marine photosynthesizers, including salt marsh grasses, mangroves, kelp, and phytoplankton. One acre of seagrass swallows around 740 pounds of carbon each year, roughly the same amount released into the atmosphere by a car covering 3,860 miles. That adds up to as much as 80 million tons annually.
Climate Desk is a journalistic collaboration dedicated to exploring the impact—human, environmental, economic, political—of a changing climate. The partners are The Atlantic, Atlas Obscura, CityLab, Grist, The Guardian, High Country News, HuffPost, Medium, Mother Jones, the National Observer, New Republic, Newsweek, Reveal, Slate, Undark, Wired. | <urn:uuid:609ba88f-9f59-4739-93cf-cbbe5f2ca2a2> | 3.875 | 527 | Knowledge Article | Science & Tech. | 32.447948 | 95,531,984 |
SOUTH AUSTRALIAN SUN-MOTHS
Synemon jcaria R. Felder, (Reddish-orange Sun-moth)
Male 36mm & Female 44mm from Mannum.
|This sun-moth differs from other large South Australian sun-moths by
having a hindwing that is mostly orange-red coloured and the forewings (in males) tend to
be narrower and the apex much more pointed. The narrow
finger-like extension of the orange-red colour in the hindwing towards the wing margin is
also a good diagnostic feature. The underside has conspicuous white markings within
the orange-red pattern. The moth has rarely been recorded in S.A., with historical
documented specimens only from the Barossa Valley, Yorke
Peninsula, and more recently near Mannum. It has very recently (late February 2014) been
recorded from northeast Eyre Peninsula and in the Upper Southeast. It has also been
recorded in nearby northwest Victoria and in Western Australia. Their wing expanse is
34-44mm and the recorded flight period is during late February-early March near Adelaide,
but there is a historic record for November on northern Yorke Peninsula. Elsewhere, the
collective flight times are from mid January to mid March.
This moth occurs in open woodland and grassland containing its larva hostplant Lomandra effusa (Scented Iron-grass) (Asparagaceae), a low growing dry-land mat-rush having narrow strap-like leaves with the ends divided into two short needle-like points. The latter shreds the wings of the female as she tries to lay eggs within the plant. This host-plant is common throughout southern S.A., and typical habitat occurs along the east side of the Mt Lofty Ranges (e.g.Callington). The eggs are laid on or between the above-ground exposed rhizomous stem parts of the hostplant base. The newly laid eggs are yellow or white, 2.5x1.1mm and have 13-19 longitudinal ridges. After laying the egg the female usually flies off to a nearby spot on the ground to rest awhile before flying off again to find another plant to lay an egg on.
Eggs in northwest Victoria take about 39-41 days to hatch. The larvae feed on the enlarged rhizomes within the internal basal parts of the host tussock, and pupation occurs in the final hollowed out larval cavity. The elongate pupa is brown, and the abdominal segments have transverse dorsal ridges enabling the pupa to have traction mobility similar to other Synemon species, e.g. S. 'Ignita' and S. selene. This would allow the pupa to move to another part of the original larval galleries in the event its pupal gallery were breached from the outside. The pupal exuvia is left protruding from the rhizome gallery after the adult moth has emerged. The life cycle is believed to take 2-3 years.
In northwest Victoria the males are known to establish mating territories (leks) within a clear area in the habitat, sometimes even utilising bare twigs or elevated stumps in a similar fashion to skippers. They will regularly challenge all flying S. jcaria males and females, and even other insects, and will not leave the lek (while sunny) until it encounters an unmated female. They will sometimes utilise hillocks or dune tops within the habitat for their leks, similar to S. discalis and S. parthenoides. In S.A. the males are more sedentary, tending to remain on or near the ground waiting for new females to fly in for mating. Similarly, if males are scarce the females will also congregate in the lek waiting for the males to fly in for mating. This sunmoth exhibits tufts of erect scales from the lateral posterior regions of the thorax which can emit pheromones, which is probably the reason the moths can be so sedentary, allowing them to conserve energy under the hot sun.
Some of the habitat this species is found in is pathetically barren of vegetation (particularly during the recent drought 2000-2010), and as they fly during the heat of late summer with temperatures that can exceed 400C, these moths can lead a pitiful existence. As its hostplant is common it is likely the moth is more extensive than documented, and overlooked due to its likely very short flight period in the middle of the summer heat. The species is threatened by farming and fire management practices, and unless the fire is very benign then all early stages of the moth will succumb, which is probably why so few colonies of the moth have been found, and the species being under dire threat. The type species came from the Adelaide region.
Resting male (left) and female (right) in open wings position; both poses showing the hindwing flash colours.
Closeup of female ovipositor (partly extended) at the end of the abdomen.
Pair of pheromone emitting tufts at rear of thorax on a female; the same occur on males.
Newly emerged Southeast female in a lekking position on a low bush in an open area near the ground
Lomandra effusa habitat in good condition.
Lomandra effusa habitat in parched condition.
Lomandra effusa (Scented iron-grass)(Asparagaceae).
White egg of Synemon jcaria showing 15 longitudinal ridges.
Photography by R. Grund
Author: R. GRUND, © copyright 11 April 2011, all rights reserved.
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A photosynthetic pigment (accessory pigment; chloroplast pigment; antenna pigment) is a pigment that is present in chloroplasts or photosynthetic bacteria and captures the light energy necessary for photosynthesis.
Plants pigments (in order of increasing polarity):
- Carotene - an orange pigment
- Xanthophyll - a yellow pigment
- Phaeophytin a - a gray-brown pigment
- Phaeophytin b - a yellow-brown pigment
- Chlorophyll a - a blue-green pigment
- Chlorophyll b - a yellow-green pigment
Chlorophyll a is the most common of the six, present in every plant that performs photosynthesis. The reason that there are so many pigments is that each absorbs light more efficiently in a different part of the electromagnetic spectrum. Chlorophyll a absorbs well at a wavelength of about 400-450 nm and at 650-700 nm; chlorophyll b at 450-500 nm and at 600-650 nm. Xanthophyll absorbs well at 400-530 nm. However, none of the pigments absorbs well in the green-yellow region, which is responsible for the abundant green we see in nature.
Like plants, the cyanobacteria use water as an electron donor for photosynthesis and therefore liberate oxygen; they also use chlorophyll as a pigment. In addition, most cyanobacteria use phycobiliproteins, water-soluble pigments which occur in the cytoplasm of the chloroplast, to capture light energy and pass it on to the chlorophylls. (Some cyanobacteria, the prochlorophytes, use chlorophyll b instead of phycobilin.) It is thought that the chloroplasts in plants and algae all evolved from cyanobacteria.
Several other groups of bacteria use the bacteriochlorophyll pigments (similar to the chlorophylls) for photosynthesis. Unlike the cyanobacteria, these bacteria do not produce oxygen; they typically use hydrogen sulfide rather than water as the electron donor.
Recently, a very different pigment has been found in some marine γ-proteobacteria: proteorhodopsin. It is similar to and probably originated from bacteriorhodopsin (see below: under Archaea). Bacterial chlorophyll b has been isolated from Rhodopseudomonas spp. but its structure is not yet known to us.
- CHLOROPHYLLS, JECFA, 1987 | <urn:uuid:0dfac4c6-b85a-4abb-8bd5-b0c229607780> | 3.8125 | 552 | Knowledge Article | Science & Tech. | 29.679986 | 95,532,003 |
An international group of marine chemists, microbiologists and geologists coordinated by the marine chemist Gregor Rehder from the Leibniz Institute of Baltic Sea Research in Warnemünde will put to sea on board of r/v Maria S. Merian on July 31, 2010. The cruise will focus on methane deposits in sediments of the Baltic Sea.
Methane is a dangerous greenhouse gas and, considering a period of 100 years, it is 23-times more effective than carbon dioxide. Thus, scientists all over the world are searching for current and potential sources of methane. The Merian expedition MSM 16/1 will concentrate on methane emissions from Baltic Sea sediments. Beside the detection of current methane emissions into water and atmosphere, the main issue on the agenda is to investigate potential changes within the methane deposits due to an increase in water temperature and ongoing eutrophication.
The seafloor of the Baltic Sea is an ideal place for methane production. There is a continuous snow of organic matter reaching the floor where its decomposition causes oxygen consumption. In the layered water body of the Baltic Sea, this leads nearly permanently to oxygen deficiency in the bottom water and constant anoxia within the sediments (anaerobic conditions). These are most favourable condi-tions for methane producing bacteria. Mayor parts of their methane production will be stored and accumulated in the sediments. Other bacterial communities, which are specialised in using methane for generating energy, provide a barrier which keeps the methane effectively scavenged in the sediments: On a global scale it is estimated that less than 10 % of the methane produced in the sediments is released from the seafloor.
This bacterially directed interaction between methane production and methane oxidation – well known from anaerobic sediments all over the world – can be studied in the Baltic Sea in an ideal way. The hypothesis: if global warming causes changes in the bacterial interaction leading to an increased release of methane from the seafloor into the water and the atmosphere, a feedback reinforcing the greenhouse effect might be expected.
In the Baltic Sea, numerous methane deposits are already known due to earlier studies. The investigations during the Merian cruise will focus on these regions. By means of a multibeam echosounder detecting gas bubbles within the water column, of various acoustic systems which virtually can look into the sediments and with innovative sensors analysing the methane concentration in the water, key areas within the Arkona, Bornholm, Gothland and Bothnian Basins will be analysed in detail. In parallel, gravity corer and a variety of other coring devices will be deployed, for the purpose of sediment sampling in these regions.
The Merian cruise is part of the international research project Baltic Gas, which is jointly funded by BONUS – the Baltic Organisations Network for Funding Sciences EEIG. It is co-ordinated by the Danish microbiologist Bo Barker Joergensen, Center for Geomicrobiology at the University of Aarhus.
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences | <urn:uuid:58da3487-cf4d-4126-8b74-c6aa24e19e55> | 3.265625 | 1,240 | Content Listing | Science & Tech. | 34.729235 | 95,532,007 |
Environment protection through recycling
MANY WOULDagree that recycling not only affects the environment but it also makes the world a better place for plants and animals to live in. News studies have established that making new products from recycled materials means less manufacturing. And subsequently with the correct methods, we can have a comfortable and convenient life without the pollution. Recycling paper products can directly preserve a large number of trees that might otherwise be used to make new paper. According to statistics, recycling a ton of mixed paper or newspaper is equivalent to saving 12 trees. Given that the trees keep the surrounding environment clean by sucking up carbon dioxide from the air we breathe. Besides paper there are a huge quantity of glass bottles and plastic containers that make a major problem for cities and private companies who operate landfill operations. If not recycled effectively, these items would need more landfill sites which itself is a gigantic task especially in urban areas exposing the surrounding population to multiple health as well as environment problems. Moreover, in case the used items do not break down at landfill sites over a time the chemicals, used in making many products, can leach into the soil, pollute the water and any plants that grow on or near that area. This is especially true with computer parts, batteries and other items that contain certain chemicals. Same is the case with the marine life which is now directly prone to the rising quantity of trash in the oceans. Scientists and divers, during the underwater research operations, have repeatedly found animals trapped and killed by plastic and other garbage they have ingested. What we desperately need right now is to make the public aware about the benefits of keeping environment clean. If we better understand how the recycling helps the environment – the more inclined we will be to embrace recycling as a natural and important part of life. Official authorities, social organizations and educational institutions can play a significant role in sensitizing the masses as well as students on environment issue. The more role must be on the part of the government that should regulate the relevant departments to make the whole waste collection as well as recycling process more effective, as it would significantly control environment degradation which is incurring about Rs. 365 billion accumulative losses to the country in terms of deforestation, floods, land erosion, damage to agriculture as well as properties.
https://www.technologytimes.pk/environment-protection-through-recycling/EditorialEnvironment,protection,Recycling MANY WOULDagree that recycling not only affects the environment but it also makes the world a better place for plants and animals to live in. News studies have established that making new products from recycled materials means less manufacturing. And subsequently with the correct methods, we can have a...Technology TimesTechnology Times email@example.comAdministratorWeb Admin Technology TimesTechnology Times | <urn:uuid:533789b5-cc75-4d08-9090-61e16c961d3b> | 3.1875 | 557 | Truncated | Science & Tech. | 26.488644 | 95,532,012 |
Dataset Details - Saproxylic Beetles of Ireland
Details of records of Saproxylic Beetles recorded in Ireland
To improve knowledge of the distirbution of Saproxylic Beetles in Ireland
Field observation and collections
The island of Ireland
From the 1800s to 2012
All records have been verified and validated by national experts
Restricted (Data can be viewed on the mapping system but is not available for download)
Dr. Roy Anderson, Saproxylic Beetles of Ireland, National Biodiversity Data Centre, Ireland, accessed 18 July 2018, <https://maps.biodiversityireland.ie/Dataset/223>
Dataset species distribution
Terrestrial Map - 10kmDistribution of the number of species recorded within each 10km grid square (ITM).
Marine Map - 50KmDistribution of the number of species recorded within each 50km grid square (WGS84).
Dataset record distribution
Terrestrial Map - 10kmDistribution of the number of records within each 10km grid square (ITM).
Marine Map - 50KmDistribution of the number of records within each 50km grid square (WGS84).
Records per year
Species per year
|Up to Year||3|
|Abundance||Measure of abundance of the organism recorded|
|Determiner name||The name of the person(s) who verified the identification - used for verify records of difficult taxa|
|Habitat description||A description of the habitat in which the organism was recorded|
|Life stage||Indication of the life stage of the organism recorded|
|Record comment||A comment associated with any individual record|
|Sampling method||Description of the sampling method employed to make the record|
|Vice-county||The name of the Watsonian (botanical) vice-county within which the record was made|
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Assessing loss of coral cover on the Great Barrier Reef: A response to Hughes et al. (2011)
Hughes et al. (Coral Reefs, 2011, in press) challenge our interpretations of the changes in coral cover observed on the Great Barrier Reef (GBR) between 1986 and 2004 (Sweatman et al. in Coral Reefs 30:521–531, 2011). They question whether we can accurately assign all causes of coral loss; we contend that this makes no difference to the observed changes. They defend the validity of historical data on coral cover from before the start of systematic large-scale monitoring and conclude that coral cover has been declining since at least 1960, but we find no trend in the early data. We remain convinced that combining data collected at different spatial scales (quadrats and transects in the past mixed with more recent whole-reef averages from manta tows) are likely to overestimate decline, because whole-reef averages will very rarely reach the high cover values that can occur at the quadrat scale. Hughes et al. (Coral Reefs, 2011, in press) state that we dismiss runoff as a cause of ecosystem degradation; we defend our interpretations and dispute some of their examples. In summary, we stand by our conclusion that coral cover on the GBR declined in the period 1986–2004 but through localised and unsynchronised changes that included recovery.
KeywordsCoral cover Meta-analyses Great Barrier Reef Degradation
We thank L. Castell, A. Cheal, P. Doherty, M. Emslie, K. Johns, M. Jonker and I. Miller for comments on drafts of this manuscript.
- Ganter R (1987) Oral history of human use and experience of crown of thorns starfish on the Great Barrier Reef. Report to the Great Barrier Reef Marine Park Authority, TownsvilleGoogle Scholar
- Hughes TP, Bellwood DR, Baird AH, Brodie J, Bruno JF, Pandolfi JM (2011) Shifting base-lines, declining coral cover, and the erosion of reef resilience. Comment on Sweatman et al. (2011) Coral Reefs: in pressGoogle Scholar
- King B, McAllister F, Wolanski E, Done T, Spagnol S (2001) River plume dynamics in the central Great Barrier Reef. In: Wolanski E (ed) Oceanographic processes of coral reefs: physical and biological links in the Great Barrier Reef. CRC Press, Boca Raton, pp 145–160Google Scholar
- Miller I (2002) Historical patterns and current trends in the broadscale distribution of crown-of-thorns starfish in the northern and central sections of the Great Barrier Reef. Proc 10th Int Coral Reef Symp 2:1273–1279Google Scholar
- Wachenfeld D (1997) Long-term trends in the status of coral reef-flat benthos: the use of historical photographs. Proceedings of the State of the Great Barrier Reef World Heritage Area Workshop. Great Barrier Reef Marine Park Authority, Townsville, pp 134–148Google Scholar
- Wolanski E, Spagnol S (2000) Pollution by mud of Great Barrier Reef coastal waters. J Coast Res 16: 1151–1156Google Scholar | <urn:uuid:4d937625-f635-4365-aac7-e5d1936548db> | 2.5625 | 684 | Academic Writing | Science & Tech. | 56.161949 | 95,532,052 |
For more than 60 years, scientists have studied the peculiar electromagnetic interaction between two neutral objects. The Casimir effect, a long-standing point of study in quantum physics, refers to this unavoidable physical force that exists between the objects, even when those objects are placed in an environment void of any external forces.
Schematic drawing of the experimental configuration used to measure the Casimir force between a gold-plated sphere and a nanonstructured grating.
The experimental data, noted by the red and blue lines, show a clear departure from normalized pressure ratings in a typical Casimir force measurement.
This recent study, published online on Sept. 27 in the Nature Communications, breaks new ground in the standard measurements of the Casimir effect known to scientists. The experiment used nanostructured (micro-ridged) metallic plates to suppress the force to a much lower rate than ever recorded previously, said Ricardo Decca, Ph.D., professor of physics at IUPUI.
“These results build upon our expertise in the measurement of the Casimir effect. At IUPUI, we have the most precise determinations of this interaction,” said Decca, one of nine co-authors in the discovery. He also is the director of the graduate program in the Department of Physics at IUPUI and co-director of the Nanoscale Imaging Center.
“Based on previous knowledge, the attraction discovered here should not have decreased as much as it did. There was still an attraction measured but not near the levels typically found,” Decca said.
He likened the experiment to “going fishing, where we caught a fish nobody ever expected to be there.”
Co-authors on the study include Vladimir A. Aksyuk, Ph.D., National Institute of Standards and Technology (NIST); Paul S. Davids, Ph.D., Sandia National Laboratories; Diego A.R. Dalvit, Ph.D., Los Alamos National Laboratory; Francesco Intravaia, Ph.D., Los Alamos National Laboratory; Stephan Koev, Ph.D., NIST; Woong Jung, Ph.D., Argonne National Laboratory; Daniel López, Ph.D., Argonne National Laboratory; A. Alec Talin, Ph.D., NIST.
Theoretical physicists differ on whether true repulsion (reversal of the attraction from positive to negative) can ever be achieved. However, the study could change scientists’ understanding of electromagnetism and lead to the creation of surfaces with less friction.Casimir effect
The reduced attraction was measured using a metal-coated sphere attached to an oscillator mounted above two electrodes. A metallic, nanostructured grating was attached to an optical fiber, and the interaction occurred as the sphere and grating were moved closer to one another. SEE FIGURE.
The experiment revealed the Casimir pressure was reduced at more than twice the expected levels when the sphere and the grating surface were separated from one another by up to 500 nanometers.
Although excited for the results thus far, the research team noted in the publication that much more analysis and study is needed to determine to true breadth of their impact. The results, however, open up new possibilities in the study of an often-debated phenomenon and could lead to more scientific activity in this field.
David Hosick | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Discussion of the distribution and abundance of living organisms and how these properties are affected by interactions between the organisms and their environment
2 posts • Page 1 of 1
I recently came across a question in an assignment. It states that a species a frog lives on the coast of California and that they range in size based on location. Smaller ones are at the top, middle in the middle and larger on the bottom. What event would most likely lead to the outcome of just small ones and large ones- whipping out the middle size. Temp change? Barrier?
If there are barriers the three populations could speciate, but, especially with reptiles and amphibians size is mostly dependent on availability of food. Where food is plentiful and good, size reaches an optimum. Other factors are temperature humidity, and possibly the ability to hide more easily. In tree frogs for instance their size is limited by the size of the bromeliad pools they lay their eggs in.
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Honey bees, especially the young, are highly sensitive to temperature and to protect developing bees, adults work together to maintain temperatures within a narrow range.
Recently published research led by Philip T. Starks, a biologist at Tufts University's School of Arts and Sciences, is the first to show that worker bees dissipate excess heat within a hive in process similar to how humans and other mammals cool themselves through their blood vessels and skin.
The top panel depicts the experimental hive. It shows that the high heat area, colored red, grew within three minutes of cooling and disappeared within nine minutes. The bottom panel shows how the control panel gradually dissipated heat. There, heat persisted after 18 minutes of cooling.
Credit: Rachael E. Bonoan, Tufts University
"This study shows how workers effectively dissipate the heat absorbed via heat-shielding, a mechanism used to thwart localized heat stressors," says Starks. The research is published in the June 10 edition of the journal Naturwissenschaften, which appeared online April 24.
This discovery also supports the theoretical construct of the bee hive as a superorganism—an entity in which its many members carry out specialized and vital functions to keep the whole functioning as a unit.
Young bees develop within wax cells. For healthy development, the youngsters must be maintained between 32 degrees Celsius, or 89.6 degrees Fahrenheit, and 35 degrees Celsius, or 95 degrees Fahrenheit. In contrast, adults can withstand temperatures as high as 50 degrees Celsius, or 122 degrees Fahrenheit
Previous research has shown that workers bees, among other duties, control the thermostat essential to the hive's survival.
When temperatures dip, worker bees create heat by contracting their thoracic muscles, similar to shivering in mammals. To protect the vulnerable brood when it's hot, workers fan the comb, spread fluid to induce evaporative cooling, or – when the heat stress is localized - absorb heat by pressing themselves against the brood nest wall (a behavior known as heat-shielding).
But until the Tufts study, scientists did not know how the bees got rid of the heat after they had absorbed it.
Starks' team included doctoral student Rachael E. Bonoan, former undergraduate student Rhyan R. Goldman, and Peter Y. Wong, a research associate professor in the department of mechanical engineering in the School of Engineering at Tufts. Bonoan and Goldman collected data on seven active honeybee hives that were framed by clear Plexiglas walls.
Each colony numbered 1,000 to 2,500 adult bees. An eighth hive, empty of bees, was used as a control. Using a theater light, the researchers raised the internal temperature of all eight hives for 15 minutes. Temperature probes recorded internal temperature throughout the heating portion of the experiment.
As anticipated, the worker bees pressed their bodies against the heated surfaces near the brood. Like insect sponges, they absorbed the heat, which lowered temperatures. After 15 minutes, a time brief enough to prevent serious harm to the bees, the theater light was turned off.
Immediately following, heat movement within the hive and external hive temperatures were tracked via thermal imaging. Within 10 minutes of cooling, temperatures in the active hives were down to safe levels. Meanwhile, the control hive remained at 40 degrees Celsius. "Since the control hive did not have bees, the differences in temperature were likely caused by worker behavior," Starks says.
Using thermal imaging, the scientists observed that temperatures increased peripheral to the heated regions of the hive as the brood nest began to cool. The thermal images clearly showed that the bees had physically moved the absorbed heat in their bodies to previously cooler areas of the hive. "Moving heat from hot to cool areas is reminiscent of the bioheat transfer via the cardiovascular system of mammals," says Starks.
This research was supported by the Tufts University Biology Department and the Tufts University National Science Foundation Research Experience for Undergraduates Program (DBI 263030).
Bonoan RE, Goldman RR, Wong PY and Starks PT. 2014. Vasculature of the Hive: heat dissipation in the honey bee (Apis mellifera) hive. Naturwissenschaften. 101: 459-465
Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate, and professional programs across the university's schools is widely encouraged.
Alex Reid | Eurek Alert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
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Climate bulletin - March 2017
Summary of the world's climate system in March 2017
The global average temperature for March 2017 as estimated from the HadCRUT4 data set was 0.88±0.14°C above the 1961-1990 average. Globally March 2017 was one of the four warmest months of March on record and most likely second warmest. Global temperature data sets maintained by NASA GISS and NOAA NCEI also show that March was a very warm month globally. Sea-surface temperatures in much of the tropical Pacific were near or above average indicating neutral ENSO conditions. However, SSTs in the eastern Tropical Pacific, close to the coast of South America, were warmer than average.
The global average land temperature for March 2017 was 1.51 ± 0.26°C above the 1961-1990 average. For global land areas March 2017 was nominally the second warmest March on record and very likely in the top five, though not the warmest. Unusual warmth – temperatures exceeding the 90th percentile for the month – was recorded in the western USA (Colorado and New Mexico were record warm), parts of Brazil, West Africa, South Africa, Madagascar, eastern Australia, parts of southern Asia and in a band running from central and southern Europe across the north of Eurasia where monthly average temperature exceeded 10°C above average across a large area. A number of countries (the Russian Federation, France, Germany and Austria each had their warmest March on record, Netherland, Serbia and Switzerland their second warmest). The temperature pattern across Eurasia and North America is consistent with the positive phase of the Arctic Oscillation. Unusual cold – temperatures below the 10th percentile for the month – affected parts of western and eastern Canada, Bangladesh and a few other limited areas: south of Lake Balgash, western Colombia, and the Falkland Islands (note that SSTs in the region of the Falkands were higher than average).
The global average sea-surface temperature for March 2017 was 0.55 ± 0.08°C above the 1961-1990 average, nominally the second warmest on record and very likely between second and fifth warmest. Sea surface temperatures in the tropical Pacific were near average with some areas warmer than the long-term mean, indicating neutral ENSO conditions. However, in the east, near the coast of South America anomalies locally exceeded 4°C. Unusually-warm waters were recorded across large areas of the North Atlantic, tropical Atlantic, the western Indian Ocean, western Pacific and around 30°S and 30°N in the Pacific Ocean. Unusually cold waters were observed in the eastern Indian Ocean. Other notable areas of colder-than-average SST were an area south of Greenland which has been colder than average for the past few years and an area in the South Atlantic which has been cooler than average since late 2015.
Higher than average precipitation totals (based on the monthly first-guess analysis by Global Precipitation Climatology Centre, GPCC) were recorded across western parts of the US, areas of South America (including Venezuela, Colombia, Ecuador, Chile and parts of Argentina), Bangladesh, parts of China and Mongolia, and New Zealand’s North Island. Tropical cyclone Enawo, which reached category 4, brought above average rainfall to Madagascar. Unusually high rainfall totals (in the top 10% of the historical record) were recorded along the east coast of Australia largely associated with severe tropical cyclone Debbie. Tropical Cyclone Blanche brought heavy rain to parts of Western Australia early in the month. In contrast, parts of South Australia recorded rainfall totals in the lowest 10%. Other areas of drier-than-average conditions included: parts of South Africa, the southeast US, Italy and some areas of east Africa where there have been longer term rainfall deficits.
Based on data from the HadISST.18.104.22.168 data set, both Northern hemisphere (Arctic) and Southern Hemisphere (Antarctic) sea ice extent were nominally the least extensive March sea ice on record for the respective hemispheres. This analysis is consistent with data from the National Snow and Ice Data Center in the US. Sea-ice extent has been unusually low in both hemispheres since the late 2016. March saw the lowest recorded daily sea ice extent for March in both hemispheres within the same week. For more details and analysis of the winter ice-extents, see the sea-ice monitoring brief. | <urn:uuid:fc8df3d5-cc4a-423c-b138-6f014e12804e> | 3.296875 | 917 | Knowledge Article | Science & Tech. | 39.374221 | 95,532,112 |
Von Neumann Architecture. It is very important that aspiring computer programmers learn about the Von Neumann Architecture, which is a generalization of almost any real computer in extant today.
For the content below, it would be most helpful if the reader has a working knowledge of the x86-64 architecture, for example, by studying the Intel and/or A.M.D. microprocessor architecture manuals. It would also be beneficial if the reader has a very good knowledge of the G.N.U. tool chain, which may be gained, if necessary, by reading G.N.U. info documentation relating to the programs `cpp', `gcc', `gas', `ld', `make', and the like (this documentation may need to be installed on your computer, as documentation is often packaged separately). If the reader wishes to learn about the C programming language (which is also very necessary for the understanding of the subsequent material in this subsection), it is recommended that the reader read Kernighan and Ritchie's book .
Boot Sector. This boot sector is mostly written in C. This code is not recommended for a production boot sector, as it makes too many assumptions about how the compiler optimizer will work in the future (i.e., it is not certain that the G.N.U. C compiler will, in future releases, optimize the size within 512 bytes, however unlikely it may be that it will become less effective). The author wrote it just to show that it is possible to write a boot sector in C.
System V A.B.I. Tutorial. This tutorial illustrates the System V A.B.I. for x86-64 Linux. For more information about this A.B.I., please refer to the official A.M.D. documentation .
i386 Linux Assembly Tutorial . This is an old tutorial covering assembly programming for i386 Linux. The A.B.I., and other details, have changed for the x86-64 architecture. However, the x86-64 C.P.U. starts out in 16 bit mode, is switched to 32 bit mode, and then subsequently switched to 64 bit mode, therefore, this tutorial retains some usefulness for x86-64 low level programming.
There is a wealth of information, located elsewhere, directly related to user space application programming. If the reader would like to know more about the standard library, the user should read the G.N.U. C library info documentation.
libdstralg. This is a data structure and algorithms library distributed under the terms of version 3.0 of the G.N.U. general public license, which is _strictly_ enforced by the Free Software Foundation.
Instrument Tuner. This is a program that generates a tone specified by a chromatic number, relative to 440 Hz, on the command line. The source code (this is a very small program) should document how this program is used. This program was written mainly to demonstrate how to use `libalsa'. However, it is also a useful program for musicians who wish to tune their instruments by ear relative to a known generated tone.
Guitar Personality. This is my music site.
Positive Poetic Perusal.
Comments, suggestions, or friendly conversation concerning the above, and other, topics will be most welcome at r DOT miyagi AT linuxprogramming DOT ca. It might be helpful to read How To Ask Questions The Smart Way . | <urn:uuid:541ac3d1-8e63-4a93-88ea-c10f1e1996c5> | 3.25 | 716 | Content Listing | Software Dev. | 61.139556 | 95,532,131 |
Climate Information Factsheet: Egypt
This factsheet summarizes current and projected climate conditions for Egypt. It can serve as a resource to the climate risk screening process for USAID strategies.
It includes information on major climate categories: temperature, precipitation and flooding, drought, sea level rise and storm surge, and winds and other storms. This is broken into current conditions, 2030 projections and 2050 projections. Full sourcing is documented.
For example, it notes that between 1960 and 2003, there has been an increase in the frequency of warm nights and a decrease in the frequency of cool nights and a general increase in average summer temperatures. By 2050, the mean annual temperature in Egypt is projected to rise by 1.64°C for the RCP4.5 median ensemble.
A drop in rainfall over northern Africa is very likely by the end of the 21st century. But there is considerable uncertainty, it states, regarding projections. Expected higher temperatures will increase the possibility of more water losses from evapotranspiration, which might reduce streamflows and stored water.
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Application of Perturbation Theory to Closed-Shell Systems
In the remaining chapters of the book we shall apply perturbation theory to different kinds of atomic systems. In the present chapter, we shall generate the diagrammatic expansion for closed-shell systems. This will enable us to represent the wave operator and the energy for such systems in a simple way by means of diagrams. The evaluation of diagrams will be considered in detail, and we shall formulate general rules for their evaluation. We shall also discuss the separation of the diagrams into radial and spin-angular parts, taking advantage of the angular-momentum graphs developed in the earlier chapters.
KeywordsWave Operator Exclusion Principle Orbital Line Single Excitation Virtual Orbital
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Plans to build a super-network designed to unlock the secrets of the universe have been announced by Professor Stephen Hawking.
The UK CosmoGrid, which will help scientists put together an accurate history of the universe, will be built using computers at universities across the UK, including Sussex, Manchester, Oxford and Portsmouth.
These will be linked to a supercomputer in Cambridge, which will oversee the programme.
Hawking explained that the network will help scientists analyse the background radiation left behind by the Big Bang.
Costing more than £2m, the CosmoGrid project is based on customised software from industry leaders SGI and Platform Computing.
Hawking told a press conference: "This analysis is very computationally challenging but it will give us unprecedented new information about the origin and present state of our universe."
Microsoft receives a 30 per cent cut of all purchases on the Xbox digital store
Credit card thieves used Apple ID accounts to buy and sell virtual currency for Clash of Clans and Clash Royale and Marvel Contest of Champions
$5.1bn fine further evidence that the EU is anti-US, claims Trump
New cable will connect Virginia to France | <urn:uuid:eeea00ab-fe02-4447-add9-895ea4a6a8b0> | 2.828125 | 236 | News Article | Science & Tech. | 30.757801 | 95,532,183 |
Winter severity is a key regulator of wildlife in the Great Lakes region. Learn how the Northeast CASC modeled how winter severity in the region might change as temperatures rise, and what these changes mean for wildlife.
Inland fisheries are critical for preventing poverty and ensuring sustainable livelihoods – but their contributions are often overlooked, say USGS National Climate Change and Wildlife Science Center researchers and partners in a new perspective paper.
Undertaking scientific projects that are useful to people - specifically land and natural resource managers - is an important part of Jeremy Littell's work for the Alaska CSC. Learn more about Jeremy and his projects in this Scientist Spotlight.
The economic and environmental health of the Southwest is closely tied to the Colorado River. Learn how researchers with the Southwest CASC discerned the important role that temperature plays in influencing the river's streamflow.
The 2017 hurricane season has heavily impacted many Caribbean countries and coastal U.S. states. Several scientists have joined together to study the impacts of these hurricanes on landscape changes and hydrology.
Check out the October 2017 issue of the Pacific Pandanus newsletter (produced by the Pacific Islands CSC), which digs into two particular extremes many in the Pacific Basin have been facing recently: high temperatures and high seas.
A team of researchers, including two from the University of Nebraska-Lincoln, have developed and proposed a new definition of drought that integrates ecological, climatic, hydrological, socioeconomic and cultural dimensions of drought.
Wisconsin's walleye is an economically and culturally important fish in the state. Yet warming temperatures may be threatening this cool-water fish's habitat. Learn about how the Northeast CASC is modeling future walleye habitat in Wisconsin. | <urn:uuid:b78e7d66-6269-403e-959e-7eb37852dda4> | 2.5625 | 344 | Content Listing | Science & Tech. | 24.465226 | 95,532,195 |
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Learn about SQLite extensions for C, Java, Perl, PHP, Python, Ruby, and Tcl. Get solid coverage of SQLite internals. Explore developing iOS (iPhone) and Android applications with SQLite.
SQLite is the solution chosen for thousands of products around the world, from mobile phones and GPS devices to set-top boxes and web browsers. You almost certainly use SQLite every day without even realizing it! | <urn:uuid:697e3369-7e98-44d7-862f-5c4f7a23e120> | 2.953125 | 286 | Product Page | Software Dev. | 30.468922 | 95,532,207 |