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To properly manage an aquifer its properties must be understood. Many properties must be known to predict how an aquifer will respond to rainfall, drought, pumping, and contamination. Considerations include where and how much water enters the groundwater from rainfall and snowmelt, how fast and in what direction the gr... | Aquifer | Wikipedia | 415 | 47481 | https://en.wikipedia.org/wiki/Aquifer | Physical sciences | Hydrology | Earth science | vital_articles |
Porosity is important, but, alone, it does not determine a rock's ability to act as an aquifer. Areas of the Deccan Traps (a basaltic lava) in west central India are good examples of rock formations with high porosity but low permeability, which makes them poor aquifers. Similarly, the micro-porous (Upper Cretaceous) C... | Aquifer | Wikipedia | 512 | 47481 | https://en.wikipedia.org/wiki/Aquifer | Physical sciences | Hydrology | Earth science | vital_articles |
In the extreme case, groundwater may exist in underground rivers (e.g., caves underlying karst topography).
Fractured
If a rock unit of low porosity is highly fractured, it can also make a good aquifer (via fissure flow), provided the rock has a hydraulic conductivity sufficient to facilitate movement of water.
Human... | Aquifer | Wikipedia | 469 | 47481 | https://en.wikipedia.org/wiki/Aquifer | Physical sciences | Hydrology | Earth science | vital_articles |
United States
The Ogallala Aquifer of the central United States is one of the world's great aquifers, but in places it is being rapidly depleted by growing municipal use, and continuing agricultural use. This huge aquifer, which underlies portions of eight states, contains primarily fossil water from the time of the l... | Aquifer | Wikipedia | 311 | 47481 | https://en.wikipedia.org/wiki/Aquifer | Physical sciences | Hydrology | Earth science | vital_articles |
Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013.25 millibars, 760mm Hg, 29.9212inchesHg, or 14.696psi. The atm unit is roug... | Atmospheric pressure | Wikipedia | 511 | 47484 | https://en.wikipedia.org/wiki/Atmospheric%20pressure | Physical sciences | Atmosphere | null | vital_articles |
Average sea-level pressure is . In aviation weather reports (METAR), QNH is transmitted around the world in hectopascals or millibars (1 hectopascal = 1 millibar), except in the United States, Canada, and Japan where it is reported in inches of mercury (to two decimal places). The United States and Canada also report s... | Atmospheric pressure | Wikipedia | 501 | 47484 | https://en.wikipedia.org/wiki/Atmospheric%20pressure | Physical sciences | Atmosphere | null | vital_articles |
Pressure on Earth varies with the altitude of the surface, so air pressure on mountains is usually lower than air pressure at sea level. Pressure varies smoothly from the Earth's surface to the top of the mesosphere. Although the pressure changes with the weather, NASA has averaged the conditions for all parts of the e... | Atmospheric pressure | Wikipedia | 508 | 47484 | https://en.wikipedia.org/wiki/Atmospheric%20pressure | Physical sciences | Atmosphere | null | vital_articles |
Measurement based on the depth of water
One atmosphere () is also the pressure caused by the weight of a column of freshwater of approximately . Thus, a diver 10.3 m under water experiences a pressure of about 2 atmospheres (1 atm of air plus 1 atm of water). Conversely, 10.3 m is the maximum height to which water can... | Atmospheric pressure | Wikipedia | 445 | 47484 | https://en.wikipedia.org/wiki/Atmospheric%20pressure | Physical sciences | Atmosphere | null | vital_articles |
An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop. Most of the approximately 440 atolls in the world are in the Pacific Ocean.
Two di... | Atoll | Wikipedia | 480 | 47486 | https://en.wikipedia.org/wiki/Atoll | Physical sciences | Oceanic and coastal landforms | null | vital_articles |
Usage
The word atoll comes from the Dhivehi word (, ). Dhivehi is an Indo-Aryan language spoken in the Maldives. The word's first recorded English use was in 1625 as atollon. Charles Darwin coined the term in his monograph, The Structure and Distribution of Coral Reefs. He recognized the word's indigenous origin and ... | Atoll | Wikipedia | 482 | 47486 | https://en.wikipedia.org/wiki/Atoll | Physical sciences | Oceanic and coastal landforms | null | vital_articles |
Bermuda is sometimes claimed as the "northernmost atoll" at a latitude of 32°18′ N. At this latitude, coral reefs would not develop without the warming waters of the Gulf Stream. However, Bermuda is termed a pseudo-atoll because its general form, while resembling that of an atoll, has a very different origin of formati... | Atoll | Wikipedia | 512 | 47486 | https://en.wikipedia.org/wiki/Atoll | Physical sciences | Oceanic and coastal landforms | null | vital_articles |
As formulated by J. E. Hoffmeister, F. S. McNeil, E. G. Prudy, and others, the antecedent karst model argues that atolls are Pleistocene features that are the direct result of the interaction between subsidence and preferential karst dissolution that occurred in the interior of flat topped coral reefs during exposure d... | Atoll | Wikipedia | 421 | 47486 | https://en.wikipedia.org/wiki/Atoll | Physical sciences | Oceanic and coastal landforms | null | vital_articles |
Coral atolls are important as sites where dolomitization of calcite occurs. Several models have been proposed for the dolomitization of calcite and aragonite within them. They are the evaporative, seepage-reflux, mixing-zone, burial, and seawater models. Although the origin of replacement dolomites remains problematic ... | Atoll | Wikipedia | 286 | 47486 | https://en.wikipedia.org/wiki/Atoll | Physical sciences | Oceanic and coastal landforms | null | vital_articles |
A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis to help find surface troughs, pressure systems and frontal boundaries.
Barom... | Barometer | Wikipedia | 345 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
On 27 July 1630, Giovanni Battista Baliani wrote a letter to Galileo Galilei explaining an experiment he had made in which a siphon, led over a hill about 21 m high, failed to work. When the end of the siphon was opened in a reservoir, the water level in that limb would sink to about 10 m above the reservoir. Galileo r... | Barometer | Wikipedia | 493 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
Evangelista Torricelli, a friend and student of Galileo, interpreted the results of the experiments in a novel way. He proposed that the weight of the atmosphere, not an attracting force of the vacuum, held the water in the tube. In a letter to Michelangelo Ricci in 1644 concerning the experiments, he wrote:
Many have... | Barometer | Wikipedia | 440 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
Because of rumors circulating in Torricelli's gossipy Italian neighbourhood, which included that he was engaged in some form of sorcery or witchcraft, Torricelli realized he had to keep his experiment secret to avoid the risk of being arrested. He needed to use a liquid that was heavier than water, and from his previou... | Barometer | Wikipedia | 468 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
The concept that decreasing atmospheric pressure predicts stormy weather, postulated by Lucien Vidi, provides the theoretical basis for a weather prediction device called a "weather glass" or a "Goethe barometer" (named for Johann Wolfgang von Goethe, the renowned German writer and polymath who developed a simple but e... | Barometer | Wikipedia | 495 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
The mercury barometer's design gives rise to the expression of atmospheric pressure in inches or millimeters of mercury (mmHg). A torr was originally defined as 1 mmHg. The pressure is quoted as the level of the mercury's height in the vertical column. Typically, atmospheric pressure is measured between and of Hg.... | Barometer | Wikipedia | 484 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
Wheel barometers
A wheel barometer uses a "J" tube sealed at the top of the longer limb. The shorter limb is open to the atmosphere, and floating on top of the mercury there is a small glass float. A fine silken thread is attached to the float which passes up over a wheel and then back down to a counterweight (usual... | Barometer | Wikipedia | 506 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
An aneroid barometer is an instrument used for measuring air pressure via a method that does not involve liquid. Invented in 1844 by French scientist Lucien Vidi, the aneroid barometer uses a small, flexible metal box called an aneroid cell (capsule), which is made from an alloy of beryllium and copper. The evacuated c... | Barometer | Wikipedia | 441 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
A barometer can also be found in smartphones such as the Samsung Galaxy Nexus, Samsung Galaxy S3-S6, Motorola Xoom, Apple iPhone 6 and newer iPhones, and Timex Expedition WS4 smartwatch, based on MEMS and piezoresistive pressure-sensing technologies. Inclusion of barometers on smartphones was originally intended to pro... | Barometer | Wikipedia | 451 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
With falling air pressure, gases trapped within the coal in deep mines can escape more freely. Thus low pressure increases the risk of firedamp accumulating. Collieries therefore keep track of the pressure. In the case of the Trimdon Grange colliery disaster of 1882 the mines inspector drew attention to the records and... | Barometer | Wikipedia | 400 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
Aneroid barometers have a mechanical adjustment that allows the equivalent sea level pressure to be read directly and without further adjustment if the instrument is not moved to a different altitude. Setting an aneroid barometer is similar to resetting an analog clock that is not at the correct time. Its dial is rotat... | Barometer | Wikipedia | 392 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
Equation
When atmospheric pressure is measured by a barometer, the pressure is also referred to as the "barometric pressure". Assume a barometer with a cross-sectional area A, a height h, filled with mercury from the bottom at Point B to the top at Point C. The pressure at the bottom of the barometer, Point B, is equal... | Barometer | Wikipedia | 333 | 47488 | https://en.wikipedia.org/wiki/Barometer | Technology | Measuring instruments | null | vital_articles |
Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradation occurs under a specific set of circumstances.
The process of biodegrada... | Biodegradation | Wikipedia | 419 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
Biofragmentation of a polymer is the lytic process in which bonds within a polymer are cleaved, generating oligomers and monomers in its place. The steps taken to fragment these materials also differ based on the presence of oxygen in the system. The breakdown of materials by microorganisms when oxygen is present is ae... | Biodegradation | Wikipedia | 358 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
In practice, almost all chemical compounds and materials are subject to biodegradation processes. The significance, however, is in the relative rates of such processes, such as days, weeks, years or centuries. A number of factors determine the rate at which this degradation of organic compounds occurs. Factors include ... | Biodegradation | Wikipedia | 428 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
The term Biodegradable Plastics refers to materials that maintain their mechanical strength during practical use but break down into low-weight compounds and non-toxic byproducts after their use. This breakdown is made possible through an attack of microorganisms on the material, which is typically a non-water-soluble ... | Biodegradation | Wikipedia | 426 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
Many plastic producers have gone so far even to say that their plastics are compostable, typically listing corn starch as an ingredient. However, these claims are questionable because the plastics industry operates under its own definition of compostable:
"that which is capable of undergoing biological decomposition in... | Biodegradation | Wikipedia | 476 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
Biodegradable technology is especially utilized by the bio-medical community. Biodegradable polymers are classified into three groups:
medical, ecological, and dual application, while in terms of origin they are divided into two groups: natural and synthetic. The Clean Technology Group is exploiting the use of supercri... | Biodegradation | Wikipedia | 488 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
Biodegradable material is capable of decomposing without an oxygen source (anaerobically) into carbon dioxide, water, and biomass, but the timeline is not very specifically defined. Similarly, compostable material breaks down into carbon dioxide, water, and biomass; however, compostable material also breaks down into i... | Biodegradation | Wikipedia | 407 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
The following studies provide examples in which composting has been defined as a subset of biodegradation in a scientific context. The first study, "Assessment of Biodegradability of Plastics Under Simulated Composting Conditions in a Laboratory Test Setting," clearly examines composting as a set of circumstances that ... | Biodegradation | Wikipedia | 494 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
In efforts to remediate the damages done by slow-degrading plastics, detergents, metals, and other pollutants created by humans, economic costs have become a concern. Marine litter in particular is notably difficult to quantify and review. Researchers at the World Trade Institute estimate that cleanup initiatives' cost... | Biodegradation | Wikipedia | 440 | 47490 | https://en.wikipedia.org/wiki/Biodegradation | Biology and health sciences | Ecology | Biology | vital_articles |
Brightness temperature or radiance temperature is a measure of the intensity of electromagnetic energy coming from a source. In particular, it is the temperature at which a black body would have to be in order to duplicate the observed intensity of a grey body object at a frequency .
This concept is used in radio astro... | Brightness temperature | Wikipedia | 490 | 47501 | https://en.wikipedia.org/wiki/Brightness%20temperature | Physical sciences | Radio astronomy | Astronomy | vital_articles |
where (the Intensity or Brightness) is the amount of energy emitted per unit surface area per unit time per unit solid angle and in the frequency range between and ; is the temperature of the black body; is the Planck constant; is frequency; is the speed of light; and is the Boltzmann constant.
For a grey body ... | Brightness temperature | Wikipedia | 351 | 47501 | https://en.wikipedia.org/wiki/Brightness%20temperature | Physical sciences | Radio astronomy | Astronomy | vital_articles |
The carbon cycle is that part of the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycle. Carbon is the main component of biological compounds as well as a maj... | Carbon cycle | Wikipedia | 505 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Carbon in the Earth's atmosphere exists in two main forms: carbon dioxide and methane. Both of these gases absorb and retain heat in the atmosphere and are partially responsible for the greenhouse effect. Methane produces a larger greenhouse effect per volume as compared to carbon dioxide, but it exists in much lower c... | Carbon cycle | Wikipedia | 472 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
The terrestrial biosphere includes the organic carbon in all land-living organisms, both alive and dead, as well as carbon stored in soils. About 500 gigatons of carbon are stored above ground in plants and other living organisms, while soil holds approximately 1,500 gigatons of carbon. Most carbon in the terrestrial b... | Carbon cycle | Wikipedia | 440 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
The ocean can be conceptually divided into a surface layer within which water makes frequent (daily to annual) contact with the atmosphere, and a deep layer below the typical mixed layer depth of a few hundred meters or less, within which the time between consecutive contacts may be centuries. The dissolved inorganic c... | Carbon cycle | Wikipedia | 418 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Most of the Earth's carbon is stored inertly in the Earth's lithosphere. Much of the carbon stored in the Earth's mantle was stored there when the Earth formed. Some of it was deposited in the form of organic carbon from the biosphere. Of the carbon stored in the geosphere, about 80% is limestone and its derivatives, w... | Carbon cycle | Wikipedia | 420 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
The slow (or deep) carbon cycle involves medium to long-term geochemical processes belonging to the rock cycle (see diagram on the right). The exchange between the ocean and atmosphere can take centuries, and the weathering of rocks can take millions of years. Carbon in the ocean precipitates to the ocean floor where i... | Carbon cycle | Wikipedia | 227 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Atmospheric particles act as cloud condensation nuclei, promoting cloud formation.
Raindrops absorb organic and inorganic carbon through particle scavenging and adsorption of organic vapors while falling toward Earth.
Burning and volcanic eruptions produce highly condensed polycyclic aromatic molecules (i.e. black carb... | Carbon cycle | Wikipedia | 509 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Continental shelves and the open ocean typically absorb CO2 from the atmosphere.
The marine biological pump sequesters a small but significant fraction of the absorbed CO2 as organic carbon in marine sediments (see below). | Carbon cycle | Wikipedia | 42 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Terrestrial runoff to the ocean
Terrestrial and marine ecosystems are chiefly connected through riverine transport, which acts as the main channel through which erosive terrestrially derived substances enter into oceanic systems. Material and energy exchanges between the terrestrial biosphere and the lithosphere as w... | Carbon cycle | Wikipedia | 453 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
The biological pump is responsible for transforming dissolved inorganic carbon (DIC) into organic biomass and pumping it in particulate or dissolved form into the deep ocean. Inorganic nutrients and carbon dioxide are fixed during photosynthesis by phytoplankton, which both release dissolved organic matter (DOM) and ar... | Carbon cycle | Wikipedia | 398 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Viruses as regulators
Viruses act as "regulators" of the fast carbon cycle because they impact the material cycles and energy flows of food webs and the microbial loop. The average contribution of viruses to the Earth ecosystem carbon cycle is 8.6%, of which its contribution to marine ecosystems (1.4%) is less than its... | Carbon cycle | Wikipedia | 474 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Carbon principally enters the mantle in the form of carbonate-rich sediments on tectonic plates of ocean crust, which pull the carbon into the mantle upon undergoing subduction. Not much is known about carbon circulation in the mantle, especially in the deep Earth, but many studies have attempted to augment our underst... | Carbon cycle | Wikipedia | 382 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Polymorphism alters carbonate compounds' stability at different depths within the Earth. To illustrate, laboratory simulations and density functional theory calculations suggest that tetrahedrally coordinated carbonates are most stable at depths approaching the core–mantle boundary. A 2015 study indicates that the lowe... | Carbon cycle | Wikipedia | 289 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Carbon in the core
Although the presence of carbon in the Earth's core is well-constrained, recent studies suggest large inventories of carbon could be stored in this region. Shear (S) waves moving through the inner core travel at about fifty percent of the velocity expected for most iron-rich alloys. Because the core... | Carbon cycle | Wikipedia | 467 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
The exchanges of carbon between the atmosphere and other components of the Earth system, collectively known as the carbon cycle, currently constitute important negative (dampening) feedbacks on the effect of anthropogenic carbon emissions on climate change. Carbon sinks in the land and the ocean each currently take up ... | Carbon cycle | Wikipedia | 352 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Halocarbons are less prolific compounds developed for diverse uses throughout industry; for example as solvents and refrigerants. Nevertheless, the buildup of relatively small concentrations (parts per trillion) of chlorofluorocarbon, hydrofluorocarbon, and perfluorocarbon gases in the atmosphere is responsible for ab... | Carbon cycle | Wikipedia | 358 | 47503 | https://en.wikipedia.org/wiki/Carbon%20cycle | Physical sciences | Earth science basics: General | Earth science | vital_articles |
Cirrus (cloud classification symbol: Ci) is a genus of high cloud made of ice crystals. Cirrus clouds typically appear delicate and wispy with white strands. In the Earth's atmosphere, cirrus are usually formed when warm, dry air rises, causing water vapor deposition onto mineral dust and metallic particles at high alt... | Cirrus cloud | Wikipedia | 412 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
Cirrus are wispy clouds made of long strands of ice crystals that are described as feathery, hair-like, or layered in appearance. First defined scientifically by Luke Howard in an 1803 paper, their name is derived from the Latin word cirrus, meaning 'curl' or 'fringe'. They are transparent, meaning that the sun can be ... | Cirrus cloud | Wikipedia | 441 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
Cirrus cloud cover varies diurnally. During the day, cirrus cloud cover drops, and during the night, it increases. Based on CALIPSO satellite data, cirrus covers an average of 31% to 32% of the Earth's surface. Cirrus cloud cover varies wildly by location, with some parts of the tropics reaching up to 70% cirrus cloud ... | Cirrus cloud | Wikipedia | 503 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
The jet stream, a high-level wind band, can stretch cirrus clouds long enough to cross continents. Jet streaks, bands of faster-moving air in the jet stream, can create arcs of cirrus cloud hundreds of kilometers long.
Cirrus cloud formation may be effected by organic aerosols (particles produced by plants) acting as ... | Cirrus cloud | Wikipedia | 396 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
Contrails
Contrails are an artificial type of cirrus cloud formed when water vapor from the exhaust of a jet engine condenses on particles, which come from either the surrounding air or the exhaust itself, and freezes, leaving behind a visible trail. The exhaust can trigger the formation of cirrus by providing ice nuc... | Cirrus cloud | Wikipedia | 385 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
Within the tropics, 36 hours prior to the center passage of a tropical cyclone, a veil of white cirrus clouds approaches from the direction of the cyclone. In the mid- to late-19th century, forecasters used these cirrus veils to predict the arrival of hurricanes. In the early 1870s the president of Belén College in Hav... | Cirrus cloud | Wikipedia | 502 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
Scientists have studied the properties of cirrus using several different methods. Lidar (laser-based radar) gives highly accurate information on the cloud's altitude, length, and width. Balloon-carried hygrometers measure the humidity of the cirrus cloud but are not accurate enough to measure the depth of the cloud. Ra... | Cirrus cloud | Wikipedia | 426 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
In addition to forming in different sizes, the ice crystals in cirrus clouds can crystallize in different shapes: solid columns, hollow columns, plates, rosettes, and conglomerations of the various other types. The shape of the ice crystals is determined by the air temperature, atmospheric pressure, and ice supersatura... | Cirrus cloud | Wikipedia | 402 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
More rarely, cirrus clouds are capable of producing glories, more commonly associated with liquid water-based clouds such as stratus. A glory is a set of concentric, faintly-colored glowing rings that appear around the shadow of the observer, and are best observed from a high viewpoint or from a plane. Cirrus clouds on... | Cirrus cloud | Wikipedia | 409 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
Cirrocumulus clouds form in sheets or patches and do not cast shadows. They commonly appear in regular, rippling patterns or in rows of clouds with clear areas between. Cirrocumulus are, like other members of the cumuliform category, formed via convective processes. Significant growth of these patches indicates high-al... | Cirrus cloud | Wikipedia | 468 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
Cirrus clouds have been observed on several other planets. In 2008, the Martian Lander Phoenix took a time-lapse photograph of a group of cirrus clouds moving across the Martian sky using lidar. Near the end of its mission, the Phoenix Lander detected more thin clouds close to the north pole of Mars. Over the course of... | Cirrus cloud | Wikipedia | 423 | 47510 | https://en.wikipedia.org/wiki/Cirrus%20cloud | Physical sciences | Clouds | null | vital_articles |
Climate variability includes all the variations in the climate that last longer than individual weather events, whereas the term climate change only refers to those variations that persist for a longer period of time, typically decades or more. Climate change may refer to any time in Earth's history, but the term is no... | Climate variability and change | Wikipedia | 511 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
A related term, climatic change, was proposed by the World Meteorological Organization (WMO) in 1966 to encompass all forms of climatic variability on time-scales longer than 10 years, but regardless of cause. During the 1970s, the term climate change replaced climatic change to focus on anthropogenic causes, as it bec... | Climate variability and change | Wikipedia | 497 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Climatic changes due to internal variability sometimes occur in cycles or oscillations. For other types of natural climatic change, we cannot predict when it happens; the change is called random or stochastic. From a climate perspective, the weather can be considered random. If there are little clouds in a particular y... | Climate variability and change | Wikipedia | 393 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
the El Niño–Southern Oscillation (ENSO) – A large scale pattern of warmer (El Niño) and colder (La Niña) tropical sea surface temperatures in the Pacific Ocean with worldwide effects. It is a self-sustaining oscillation, whose mechanisms are well-studied. ENSO is the most prominent known source of inter-annual variabil... | Climate variability and change | Wikipedia | 495 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
the Arctic oscillation (AO) and Antarctic oscillation (AAO) – The annular modes are naturally occurring, hemispheric-wide patterns of climate variability. On timescales of weeks to months they explain 20–30% of the variability in their respective hemispheres. The Northern Annular Mode or Arctic oscillation (AO) in the ... | Climate variability and change | Wikipedia | 213 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Ocean current changes
The oceanic aspects of climate variability can generate variability on centennial timescales due to the ocean having hundreds of times more mass than in the atmosphere, and thus very high thermal inertia. For example, alterations to ocean processes such as thermohaline circulation play a key rol... | Climate variability and change | Wikipedia | 484 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Since the Industrial Revolution, humanity has been adding to greenhouse gases by emitting CO2 from fossil fuel combustion, changing land use through deforestation, and has further altered the climate with aerosols (particulate matter in the atmosphere), release of trace gases (e.g. nitrogen oxides, carbon monoxide, or ... | Climate variability and change | Wikipedia | 433 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Solar output
The Sun is the predominant source of energy input to the Earth's climate system. Other sources include geothermal energy from the Earth's core, tidal energy from the Moon and heat from the decay of radioactive compounds. Both long term variations in solar intensity are known to affect global climate. Sola... | Climate variability and change | Wikipedia | 474 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
At a larger scale—a few times every 50 million to 100 million years—the eruption of large igneous provinces brings large quantities of igneous rock from the mantle and lithosphere to the Earth's surface. Carbon dioxide in the rock is then released into the atmosphere.
Small eruptions, with injections of less than 0.1 ... | Climate variability and change | Wikipedia | 493 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Evidence exists that the Chicxulub asteroid impact some 66 million years ago had severely affected the Earth's climate. Large quantities of sulfate aerosols were kicked up into the atmosphere, decreasing global temperatures by up to 26 °C and producing sub-freezing temperatures for a period of 3–16 years. The recovery ... | Climate variability and change | Wikipedia | 477 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Various archives of past climate are present in rocks, trees and fossils. From these archives, indirect measures of climate, so-called proxies, can be derived. Quantification of climatological variation of precipitation in prior centuries and epochs is less complete but approximated using proxies such as marine sedimen... | Climate variability and change | Wikipedia | 486 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Analysis and uncertainties
One difficulty in detecting climate cycles is that the Earth's climate has been changing in non-cyclic ways over most paleoclimatological timescales. Currently we are in a period of anthropogenic global warming. In a larger timeframe, the Earth is emerging from the latest ice age, cooling fr... | Climate variability and change | Wikipedia | 454 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Larger, faster or more radical changes, however, may result in vegetation stress, rapid plant loss and desertification in certain circumstances. An example of this occurred during the Carboniferous Rainforest Collapse (CRC), an extinction event 300 million years ago. At this time vast rainforests covered the equatorial... | Climate variability and change | Wikipedia | 500 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Sea ice
Sea ice plays an important role in Earth's climate as it affects the total amount of sunlight that is reflected away from the Earth. In the past, the Earth's oceans have been almost entirely covered by sea ice on a number of occasions, when the Earth was in a so-called Snowball Earth state, and completely ice-... | Climate variability and change | Wikipedia | 385 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
The Cenozoic
Throughout the Cenozoic, multiple climate forcings led to warming and cooling of the atmosphere, which led to the early formation of the Antarctic ice sheet, subsequent melting, and its later reglaciation. The temperature changes occurred somewhat suddenly, at carbon dioxide concentrations of about 600–76... | Climate variability and change | Wikipedia | 488 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Solar activity may have contributed to part of the modern warming that peaked in the 1930s. However, solar cycles fail to account for warming observed since the 1980s to the present day. Events such as the opening of the Northwest Passage and recent record low ice minima of the modern Arctic shrinkage have not taken pl... | Climate variability and change | Wikipedia | 484 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Regional variability observations permit study of regionalized climate tipping points such as rainforest loss, ice sheet and sea ice melt, and permafrost thawing. Such distinctions underlie research into a possible global cascade of tipping points. | Climate variability and change | Wikipedia | 45 | 47512 | https://en.wikipedia.org/wiki/Climate%20variability%20and%20change | Physical sciences | Climatology | null | vital_articles |
Numerical climate models (or climate system models) are mathematical models that can simulate the interactions of important drivers of climate. These drivers are the atmosphere, oceans, land surface and ice. Scientists use climate models to study the dynamics of the climate system and to make projections of future clim... | Climate model | Wikipedia | 421 | 47513 | https://en.wikipedia.org/wiki/Climate%20model | Physical sciences | Climate change | Earth science | vital_articles |
There are three major types of institution where climate models are developed, implemented and used:
National meteorological services: Most national weather services have a climatology section.
Universities: Relevant departments include atmospheric sciences, meteorology, climatology, and geography.
National and inte... | Climate model | Wikipedia | 469 | 47513 | https://en.wikipedia.org/wiki/Climate%20model | Physical sciences | Climate change | Earth science | vital_articles |
Zero-dimensional models consider Earth as a point in space, analogous to the pale blue dot viewed by Voyager 1 or an astronomer's view of very distant objects. This dimensionless view while highly limited is still useful in that the laws of physics are applicable in a bulk fashion to unknown objects, or in an appro... | Climate model | Wikipedia | 489 | 47513 | https://en.wikipedia.org/wiki/Climate%20model | Physical sciences | Climate change | Earth science | vital_articles |
The calculated emissivity can be compared to available data. Terrestrial surface emissivities are all in the range of 0.96 to 0.99 (except for some small desert areas which may be as low as 0.7). Clouds, however, which cover about half of the planet's surface, have an average emissivity of about 0.5 (which must be redu... | Climate model | Wikipedia | 449 | 47513 | https://en.wikipedia.org/wiki/Climate%20model | Physical sciences | Climate change | Earth science | vital_articles |
Radiative-convective models have advantages over simpler models and also lay a foundation for more complex models. They can estimate both surface temperature and the temperature variation with elevation in a more realistic manner. They also simulate the observed decline in upper atmospheric temperature and rise in s... | Climate model | Wikipedia | 505 | 47513 | https://en.wikipedia.org/wiki/Climate%20model | Physical sciences | Climate change | Earth science | vital_articles |
Simple box models, i.e. box model with a small number of boxes whose properties (e.g. their volume) do not change with time, are often useful to derive analytical formulas describing the dynamics and steady-state abundance of a species. More complex box models are usually solved using numerical techniques.
Box models ... | Climate model | Wikipedia | 479 | 47513 | https://en.wikipedia.org/wiki/Climate%20model | Physical sciences | Climate change | Earth science | vital_articles |
Techniques that could lead to energy savings, include for example: "reducing floating point precision computation; developing machine learning algorithms to avoid unnecessary computations; and creating a new generation of scalable numerical algorithms that would enable higher throughput in terms of simulated years per ... | Climate model | Wikipedia | 59 | 47513 | https://en.wikipedia.org/wiki/Climate%20model | Physical sciences | Climate change | Earth science | vital_articles |
In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles, suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of satur... | Cloud | Wikipedia | 494 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
In the stratosphere and mesosphere, clouds have common names for their main types. They may have the appearance of stratiform veils or sheets, cirriform wisps, or stratocumuliform bands or ripples. They are seen infrequently, mostly in the polar regions of Earth. Clouds have been observed in the atmospheres of other pl... | Cloud | Wikipedia | 483 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
History of cloud science
Ancient cloud studies were not made in isolation, but were observed in combination with other weather elements and even other natural sciences. Around 340 BC, Greek philosopher Aristotle wrote Meteorologica, a work which represented the sum of knowledge of the time about natural science, inclu... | Cloud | Wikipedia | 502 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Terrestrial clouds can be found throughout most of the homosphere, which includes the troposphere, stratosphere, and mesosphere. Within these layers of the atmosphere, air can become saturated as a result of being cooled to its dew point or by having moisture added from an adjacent source. In the latter case, saturatio... | Cloud | Wikipedia | 498 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Clouds formed by any of these lifting agents are initially seen in the troposphere where these agents are most active. However, water vapor that has been lifted to the top of troposphere can be carried even higher by gravity waves where further condensation can result in the formation of clouds in the stratosphere and... | Cloud | Wikipedia | 298 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Nonconvective stratiform clouds appear in stable airmass conditions and, in general, have flat, sheet-like structures that can form at any altitude in the troposphere. The stratiform group is divided by altitude range into the genera cirrostratus (high-level), altostratus (mid-level), stratus (low-level), and nimbostra... | Cloud | Wikipedia | 416 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Cumuliform clouds generally appear in isolated heaps or tufts. They are the product of localized but generally free-convective lift where no inversion layers are in the troposphere to limit vertical growth. In general, small cumuliform clouds tend to indicate comparatively weak instability. Larger cumuliform types are ... | Cloud | Wikipedia | 169 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Levels and genera
Tropospheric clouds form in any of three levels (formerly called étages) based on altitude range above the Earth's surface. The grouping of clouds into levels is commonly done for the purposes of cloud atlases, surface weather observations, and weather maps. The base-height range for each level varie... | Cloud | Wikipedia | 300 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Genus cirrus (Ci) – these are mostly fibrous wisps of delicate, white, cirriform, ice crystal clouds that show up clearly against the blue sky. Cirrus are generally non-convective except castellanus and floccus subtypes which show limited convection. They often form along a high altitude jetstream and at the very leadi... | Cloud | Wikipedia | 450 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Genus altocumulus (Ac) – This is a midlevel cloud layer of limited convection that is usually appears in the form of irregular patches or more extensive sheets arranged in groups, lines, or waves. Altocumulus may occasionally resemble cirrocumulus, but is usually thicker and composed of a mix of water droplets and ice ... | Cloud | Wikipedia | 482 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
These clouds have low- to mid-level bases that form anywhere from near the surface to about and tops that can extend into the mid-altitude range and sometimes higher in the case of nimbostratus.
Genus nimbostratus (Ns) – This is a diffuse, dark gray, multi-level stratiform layer with great horizontal extent and usual... | Cloud | Wikipedia | 500 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Species cumulus congestus – Increasing airmass instability can cause free-convective cumulus to grow very tall to the extent that the vertical height from base to top is greater than the base-width of the cloud. The cloud base takes on a darker gray coloration and the top commonly resembles a cauliflower. This cloud ty... | Cloud | Wikipedia | 446 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
Stable or mostly stable
Of the non-convective stratiform group, high-level cirrostratus comprises two species. Cirrostratus nebulosus has a rather diffuse appearance lacking in structural detail. Cirrostratus fibratus is a species made of semi-merged filaments that are transitional to or from cirrus. Mid-level altostra... | Cloud | Wikipedia | 494 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null | vital_articles |
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