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8,500 | Comment on Enhanced TKE Dissipation under Breaking Waves | physics.ao-ph | It is noted that the results of recent experiments on the enhancement of
turbulent kinetic energy (TKE) dissipation below surface waves can be stated as
follows. TKE dissipation is enhanced by a factor $15 H_{ws}/z$ at depths $0.5
H_{ws} < z < 20 H_{ws}$ with respect to the wall-layer result $\epsilon =
u_{*w}^3/\kappa... | physics |
8,501 | On the mechanism of decadal oscillations in a coarse resolution ocean model | physics.ao-ph | The mechanism that causes an interdecadal oscillation in a coarse resolution
sector ocean model forced by mixed boundary conditions is studied. The
oscillation is characterized by large fluctuations in convective activity and
air/sea heat exchange on a decadal time scale. When the convective activity is
large, a streng... | physics |
8,502 | A comparison of two operational wave assimilation methods | physics.ao-ph | A comparison is carried out between two operational wave
forecasting/assimilation models for the North Sea, with the emphasis on the
assimilation schemes. One model is the WAM model, in combination with an
optimal interpolation method (OIP). The other model, DASWAM, consists of the
third generation wave model PHIDIAS i... | physics |
8,503 | The El Nino Stochastic Oscillator | physics.ao-ph | Anomalies during an El Nino are dominated by a single, irregularly
oscillating, mode. Equatorial dynamics has been linked to delayed-oscillator
models of this mode. Usually, the El Nino mode is regarded as an unstable mode
of the coupled atmosphere system and the irregularity is attributed to noise
and possibly chaos. ... | physics |
8,504 | On the El-Nino Teleconnection to Spring Precipitation in Europe | physics.ao-ph | In a statistical analysis of more than a century of data we find a strong
connection between strong warm El Nino winter events and high spring
precipitation in a band from Southern England eastwards into Asia. This
relationship is an extension of the connection mentioned by Kiladis and Diaz
(1989), and much stronger th... | physics |
8,505 | 11-Year Warm Cloud Modification Experiment in Maharashtra State, India | physics.ao-ph | A warm cloud modification experiment was carried out in an area of 4800 Sq.Km
in the Pune region,India, during the 11-summer monsoon (June-September) seasons
(1973-74, 1976, 1979-86). A double-area cross-over design with area
randomization was adopted and an instrumented aircraft was used for seeding and
cloud physical... | physics |
8,506 | A possible explanation for Earth's climatic changes in the past few million years | physics.ao-ph | The astronomical theory of Milankovitch relates the changes of Earth' past
climate to variations in insolation caused by oscillations of the orbital
parameters. However, this theory has problems to account for some major
observed phenomena of the past few million years. Here, we present an
alternative explanation for t... | physics |
8,507 | Using Rigorous Ray Tracing to Incorporate Reflection into the Parabolic Approximation | physics.ao-ph | We present a parabolic approximation that incorporates reflection. With this
approximation, there is no need to solve the parabolic equation for a coupled
pair of solutions consisting of the incident and reflected waves. Rather, this
approximation uses a synthetic wave whose spectral components manifest the
incident an... | physics |
8,508 | Radiation of mixed layer near-inertial oscillations into the ocean interior | physics.ao-ph | The radiation from the mixed layer into the interior of the ocean of
near-inertial oscillations excited by a passing storm in the presence of the
beta effect is reconsidered as an initial-value problem. Making use of the fact
that the mixed layer depth is much smaller than the total depth of the ocean,
the solution is ... | physics |
8,509 | Monodisperse approximation in the metastable phase decay | physics.ao-ph | A new simple method for the first order phase transition kinetics is
suggested. The metastable phase consumption can be imagined in frames of the
modisperse approximation for the distribution of the droplets sizes. In all
situations of the metastable phase decay this approximation leads to negligible
errors in the tota... | physics |
8,510 | On the effect of small-scale oceanic variability on topography-generated currents | physics.ao-ph | Small-scale oceanic motions, in combination with bottom topography, induce
mean large-scale along-isobaths flows. The direction of these mean flows is
usually found to be anticyclonic (cyclonic) over bumps (depressions). Here we
employ a quasigeostrophic model to show that the current direction of these
topographically... | physics |
8,511 | A non-linear optimal estimation inverse method for radio occultation measurements of temperature, humidity and surface pressure | physics.ao-ph | An optimal estimation inverse method is presented which can be used to
retrieve simultaneously vertical profiles of temperature and specific humidity,
in addition to surface pressure, from satellite-to-satellite radio occultation
observations of the Earth's atmosphere. The method is a non-linear, maximum
{\it a posteri... | physics |
8,512 | A New Hypothesis for Layers of High Reflectivity Seen in MST Radar Observations | physics.ao-ph | Analysis of MST radar observations at Gadanki (near Tirupati, India), for a
period of 14 months from 1995 September to 1996 November, shows that "Clear air
Turbulence" is not the primary source of high MST radar reflectivity; this
conventional idea needs to be modified. An alternative hypothesis based on the
microphysi... | physics |
8,513 | Remote sensing of bubble clouds in seawater | physics.ao-ph | We report on the influence of submerged bubble clouds on the remote sensing
properties of water. We show that the optical effect of bubbles on radiative
transfer and on the estimate of the ocean color is significant. We present a
global map of the volume fraction of air in water derived from daily wind speed
data. This... | physics |
8,514 | Monte Carlo study of the scattering error of a quartz reflective absorption tube | physics.ao-ph | A Monte Carlo model was used to study the scattering error of an absorption
meter with a divergent light beam and a limited acceptance angle of the
receiver. Reflections at both ends of the tube were taken into account.
Calculations of the effect of varying optical properties of water, as well as
the receiver geometry,... | physics |
8,515 | Asymptotic light field in the presence of a bubble-layer | physics.ao-ph | We report that the submerged microbubbles are an efficient source of diffuse
radiance and may contribute to a rapid transition to the diffuse asymptotic
regime. In this asymptotic regime an average cosine is easily predictable and
measurable. | physics |
8,516 | Improvements of the Discrete Dipole Approximation method | physics.ao-ph | The discrete-dipole approximation (DDA) is a flexible technique for computing
scattering and absorption by targets of arbitrary geometry. In this paper we
perform systematic study of various non-stationary iterative (conjugate
gradient) methods in search for the most efficient one in order to solve the
system of equati... | physics |
8,517 | PARIS Interferometric Processor Analysis and Experimental Results: Theoretical Feasibility Analysis | physics.ao-ph | Several experimental results show that it is possible to extract useful phase
information from reflected GPS signals over the oceans. In this work we begin
the development of the theoretical background to account for these results and
fully understand the phenomena involved. This information will then be used to
define... | physics |
8,518 | Modelling horizontal and vertical concentration profiles of ozone and oxides of nitrogen within high-latitude urban area | physics.ao-ph | A Lagrangian column model has been developed to simulate the mean (monthly
and annual) three-dimensional structure in ozone and nitrogen oxides
concentrations in the boundary layer within and immediately around an urban
area. Short time-scale photochemical processes of ozone, as well as emissions
and deposition to the ... | physics |
8,519 | The Day-night Variation of Cosmic Rays Instensity at Sea Level Under the Influence of Meteorological Fronts and Troughs | physics.ao-ph | The day-night variation of cosmic rays intensity at sea level has been
observed by a simple G-M counter telescope. We preform two 5 hours counting
during the day and night and find that the pattern of variation is closely
related to the atmospheric disturbance, especially when the observation station
is being affected ... | physics |
8,520 | Evaluating the quality of ground-based microwave radiometer measurements and retrievals using detrended fluctuation and spectral analysis methods | physics.ao-ph | Time series both of microwave radiometer brightness temperature measurements
at 23.8 and 31.4 GHz and of retrievals of water vapor and liquid water path
from these brightness temperatures are evaluated using the detrended
fluctuation analysis method. As quantified by the parameter $\alpha$, this
method (i) enables iden... | physics |
8,521 | Relationship between sunspot number and total annual precipitation at Izana (Tenerife): Maximum precipitation prediction with three year lagged sunspots? | physics.ao-ph | A possible relationship between sunspot number and total annual precipitation
from the Izana Observatory has been found. The annual precipitation period
ranges from 1916 to 1998, thus including nearly eight 11-year solar cycles.
When points of total precipitation for a given year at Izana are plotted on
the ordinate ... | physics |
8,522 | Universality and Scale Invariance in Hourly Rainfall | physics.ao-ph | We show that the hourly rainfall rate distribution can be described by a
simple power law to a good approximation. We show that the exponent of the
distribution in tropics is universal and is equal to $1.13\pm 0.11$. At higher
latitudes the exponent increases and is found to lie in the range 1.3-1.6. | physics |
8,523 | Stability of Rossby waves in the beta-plane approximation | physics.ao-ph | Floquet theory is used to describe the unstable spectrum at large scales of
the beta-plane equation linearized about Rossby waves. Base flows consisting of
one to three Rossby wave are considered analytically using continued fractions
and the method of multiple scales, while base flow with more than three Rossby
waves ... | physics |
8,524 | Global warming: What does the data tell us? | physics.ao-ph | We analyze global surface temperature data obtained at 13472 weather stations
from the year 1702 to 1990. The mean annual temperature of a station fluctuates
from year to year by typically +-0.6oC (one standard deviation). Superimposed
on this fluctuation is a linear increase of the temperature by typically 0.40oC
per ... | physics |
8,525 | GPM Draft Science Implementation Plan Ground Validation Chapter | physics.ao-ph | The validation of NASA Global Precipitation Mission (GPM) satellite
precipitation products is important for their credibility and utility within
the larger community. This document defines GPM ground validation scientific
objectives and several programmatic components for meeting those objectives.
Multi-year, multi-sen... | physics |
8,526 | Stability of Semi-Implicit and Iterative Centred-Implicit Time Discretizations for Various Equation Systems Used in NWP | physics.ao-ph | The stability of classical semi-implicit scheme, and some more advanced
iterative schemes recently proposed for Numerical Weather Prediction (NWP)
purpose is examined. In all these schemes, the solution of the centred-implicit
non-linear equation is approached by an iterative fixed-point algorithm,
preconditioned by a ... | physics |
8,527 | Characteristics of Aerosol Spectral Optical Depths over Manora Peak, Nainital $-$ A High Altitude Station in the Central Himalayas | physics.ao-ph | We present, for the first time, spectral behaviour of aerosol optical depths
(AODs) over Manora Peak, Nainital located at an altitude of $\sim$ 2 km in the
Shivalik ranges of central Himalayas. The observations were carried out using a
Multi-Wavelength solar Radiometer during January to December 2002. The main
results ... | physics |
8,528 | Cloud boundary height measurements using lidar and radar | physics.ao-ph | Using only lidar or radar an accurate cloud boundary height estimate is often
not possible. The combination of lidar and radar can give a reliable cloud
boundary estimate in a much broader range of cases. However, also this
combination with standard methods still can not measure the cloud boundaries in
all cases. This ... | physics |
8,529 | Constrained-Hamiltonian Shallow-Water Dynamics on the Sphere | physics.ao-ph | Salmon's nearly geostrophic model for rotating shallow-water flow is derived
in full spherical geometry. The model, which results upon constraining the
velocity field to the height field in Hamilton's principle for rotating
shallow-water dynamics, constitutes an important prototype of Hamiltonian
balanced models. Inste... | physics |
8,530 | Deep ocean influence on upper ocean baroclinic instability saturation | physics.ao-ph | In this paper we extend earlier results regarding the effects of the lower
layer of the ocean (below the thermocline) on the baroclinic instability within
the upper layer (above the thermocline). We confront quasigeostrophic
baroclinic instability properties of a 2.5-layer model with those of a 3-layer
model with a ver... | physics |
8,531 | Use of the likelihood for measuring the skill of probabilistic forecasts | physics.ao-ph | We define the likelihood and give a number of justifications for its use as a
skill measure for probabilistic forecasts. We describe a number of different
scores based on the likelihood, and briefly investigate the relationships
between the likelihood, the mean square error and the ignorance. | physics |
8,532 | A New Framework for the Assessment and Calibration of Medium Range Ensemble Temperature Forecasts | physics.ao-ph | We present a new framework for the assessment and calibration of medium range
ensemble temperature forecasts. The method is based on maximising the
likelihood of a simple parametric model for the temperature distribution, and
leads to some new insights into the predictability of uncertainty. | physics |
8,533 | Development of an elementary climate model: two-layer cellular case | physics.ao-ph | A qualitative understanding of the greenhouse effect has long been available
through models based on globally- and time-averaged quantities. We examine here
a simple 864-cell climatological model that emphasizes vertical radiative
energy transport within each cell. It reproduces yearly average temperatures
obtained ear... | physics |
8,534 | The Assessment and Calibration of Ensemble Seasonal Forecasts of Equatorial Pacific Ocean Temperature and the Predictability of Uncertainty | physics.ao-ph | We evaluate the performance of two 44 year ensemble seasonal hindcast time
series for the Nino3 index produced as part of the DEMETER project. We show
that the ensemble mean carries useful information out to six months. The
ensemble spread, however, only carries useful information out to four months in
one of the model... | physics |
8,535 | Moment based methods for ensemble assessment and calibration | physics.ao-ph | We describe various moment-based ensemble interpretation models for the
construction of probabilistic temperature forecasts from ensembles. We apply
the methods to one year of medium range ensemble forecasts and perform in and
out of sample testing. Our main conclusion is that probabilistic forecasts
derived from the e... | physics |
8,536 | Lagrangian turbulence in the Adriatic Sea as computed from drifter data: effects of inhomogeneity and nonstationarity | physics.ao-ph | The properties of mesoscale Lagrangian turbulence in the Adriatic Sea are
studied from a drifter data set spanning 1990-1999, focusing on the role of
inhomogeneity and nonstationarity. A preliminary study is performed on the
dependence of the turbulent velocity statistics on bin averaging, and a
preferential bin scale ... | physics |
8,537 | A note on the use of the word 'likelihood' in statistics and meteorology | physics.ao-ph | We highlight the different uses of the word 'likelihood' that have arisen in
statistics and meteorology, and make the recommendation that one of these uses
should be dropped to prevent confusion and misunderstanding. | physics |
8,538 | Five guidelines for the evaluation of site-specific medium range probabilistic temperature forecasts | physics.ao-ph | Probabilistic temperature forecasts are potentially useful to the energy and
weather derivatives industries. However, at present, they are little used.
There are a number of reasons for this, but we believe this is in part due to
inadequacies in the methodologies that have been used to evaluate such
forecasts, leading ... | physics |
8,539 | Comparing the ensemble mean and the ensemble standard deviation as inputs for probabilistic medium-range temperature forecasts | physics.ao-ph | We ask the following question: what are the relative contributions of the
ensemble mean and the ensemble standard deviation to the skill of a
site-specific probabilistic temperature forecast? Is it the case that most of
the benefit of using an ensemble forecast to predict temperatures comes from
the ensemble mean, or f... | physics |
8,540 | Do probabilistic medium-range temperature forecasts need to allow for non-normality? | physics.ao-ph | The gaussian spread regression model for the calibration of site specific
ensemble temperature forecasts depends on the apparently restrictive assumption
that the uncertainty around temperature forecasts is normally distributed. We
generalise the model using the kernel density to allow for much more flexible
distributi... | physics |
8,541 | Do medium range ensemble forecasts give useful predictions of temporal correlations? | physics.ao-ph | Medium range ensemble forecasts are typically used to derive predictions of
the conditional marginal distributions of future events on individual days. We
assess whether they can also be used to predict the conditional correlations
between different days. | physics |
8,542 | The dependence of relative dispersion on turbulence scales in Lagrangian Stochastic Models | physics.ao-ph | The aim of the article is to investigate the relative dispersion properties
of the Well Mixed class of Lagrangian Stochastic Models. Dimensional analysis
shows that given a model in the class, its properties depend solely on a
non-dimensional parameter, which measures the relative weight of
Lagrangian-to-Eulerian scale... | physics |
8,543 | Universality in snowflake aggregation | physics.ao-ph | Aggregation of ice crystals is a key process governing precipitation.
Individual ice crystals exhibit considerable diversity of shape, and a wide
range of physical processes could influence their aggregation; despite this we
show that a simple computer model captures key features of aggregate shape and
size distributio... | physics |
8,544 | Stability of leap-frog constant-coefficients semi-implicit schemes for the fully elastic system of Euler equations. Flat-terrain case | physics.ao-ph | The aim of this paper is to investigate the response of this system/scheme in
terms of stability in presence of explicitly treated residual terms, as it
inevitably occurs in the reality of NWP. This sudy is restricted to the impact
of thermal and baric residual terms (metric residual terms linked to the
orography are n... | physics |
8,545 | On the Use of a Wider Class of Linear Systems for the Design of Constant-Coefficients Semi-Implicit Time-Schemes in NWP | physics.ao-ph | The linearization of the meteorological equations around a specified
reference state, usually applied in NWP to define the linear system of
constant-coefficients semi-implicit schemes, is outlined as an unnecessarily
restrictive approach which may be detrimental in terms of stability. It is
shown theoretically that an ... | physics |
8,546 | A theory of growth by differential sedimentation with application to snowflake formation | physics.ao-ph | A simple model of irreversible aggregation under differential sedimentation
of particles in a fluid is presented. The structure of the aggregates produced
by this process is found to feed back on the dynamics in such a way as to
stabilise both the exponents controlling the growth rate, and the fractal
dimension of the ... | physics |
8,547 | Multilayer shallow-water model with stratification and shear | physics.ao-ph | The purpose of this paper is to present a shallow-water-type model with
multiple inhomogeneous layers featuring variable linear velocity vertical shear
and startificaion in horizontal space and time. This is achieved by writing the
layer velocity and buoyancy fields as linear functions of depth, with
coefficients that ... | physics |
8,548 | Weather forecasts, Weather derivatives, Black-Scholes, Feynmann-Kac and Fokker-Planck | physics.ao-ph | We investigate the relationships between weather forecasting, weather
derivatives, the Black-Scholes equation, Feynmann-Kac theory and the
Fokker-Planck equation. There is one useful result, but on the whole the
relations we present seem to be more interesting than practically useful. | physics |
8,549 | The problem with the Brier score | physics.ao-ph | The Brier score is frequently used by meteorologists to measure the skill of
binary probabilistic forecasts. We show, however, that in simple idealised
cases it gives counterintuitive results. We advocate the use of an alternative
measure that has a more compelling intuitive justification. | physics |
8,550 | Linear waves and baroclinic instability in an inhomogeneous-density layered primitive-equation ocean model | physics.ao-ph | We consider a multilayer generalization of Ripa's inhomogeneous-density
single-layer primitive-equation model. In addition to vary arbitrarily in
horizontal position and time, the horizontal velocity and buoyancy fields are
allowed to vary linearly with depth within each layer of the model. Preliminary
results on linea... | physics |
8,551 | GPM Ground Validation Basic Radar Products and Implications for Observation Strategies | physics.ao-ph | Recommendations are made for NASA/JAXA Global Precipitation Measurement (GPM)
satellite Ground Validation (GV) program. This report details recommended GV
site local radar products based on data from surface-based scanning radars
including S-band, C-band, and X-band polarimetric and non-polarimetric radars.
Three gener... | physics |
8,552 | On the sensitivity of coastal quasigeostrophic edge wave interaction to bottom boundary characteristics: possible implications for eddy parameterizations | physics.ao-ph | The Eady problem of baroclinic instability as applicable to quasi-geostrophic
oceanic flows with zero internal PV gradients is revisited by introducing a
mild slope and Ekman pumping on the lower boundary. The solution behaviour is
determined by the isopycnal slope relative to either the bottom slope or the
ratio of Ek... | physics |
8,553 | Improving probabilistic weather forecasts using seasonally varying calibration parameters | physics.ao-ph | We show that probabilistic weather forecasts of site specific temperatures
can be dramatically improved by using seasonally varying rather than constant
calibration parameters. | physics |
8,554 | Singular vector ensemble forecasting systems and the prediction of flow dependent uncertainty | physics.ao-ph | The ECMWF ensemble weather forecasts are generated by perturbing the initial
conditions of the forecast using a subset of the singular vectors of the
linearised propagator. Previous results show that when creating probabilistic
forecasts from this ensemble better forecasts are obtained if the mean of the
spread and the... | physics |
8,555 | On the Formulation of Lagrangian Stochastic Models for Geophysical Turbulent Flows | physics.ao-ph | This paper has been withdrawn by the author(s), due to a crucial error in eq.
6. | physics |
8,556 | Generalized Paraxial Ray Trace Procedure Derived from Geodesic Deviation | physics.ao-ph | Paraxial ray tracing procedures have become widely accepted techniques for
acoustic models in seismology and underwater acoustics. To date a generic form
of these procedures including fluid motion and time dependence has not appeared
in the literature. A detailed investigation of the characteristic curves of the
equati... | physics |
8,557 | Estimate of drainage water behaviour in shallow lakes | physics.ao-ph | A theoretical estimate of the explicit time dependence of a drainage water of
shallow lakes is presented as an important contribution for understanding the
lake dynamics. This information can be obtained from a sum of functions,
largely used in fitting of experimental data. These functions were chosen
because their cen... | physics |
8,558 | An Analytical Theory for the Early Stage of the Development of Hurricanes: Part I | physics.ao-ph | A theoretical formulation for the early stage (Tropical Storm stage) of
hurricane development is proposed. These solutions are not only consistent with
observations but also offer some new insights into hurricane properties. This
is the first time a theoretical model for the early growing of hurricanes is
proposed for ... | physics |
8,559 | A link between an ice age era and a rapid polar shift | physics.ao-ph | The striking asymmetry of the ice cover during the Last Global Maximum
suggests that the North Pole was in Greenland and then rapidly shifted to its
present position in the Arctic See. A scenario which causes such a rapid
geographic polar shift is physically possible. It involves an additional
planet, which disappeared... | physics |
8,560 | Cosmic Rays and Solar Insolation as the Main Control Parameters of the Catastrophe Theory of Climatic Response to Orbital Variations | physics.ao-ph | The energy-balance model of global climate, which is taking into account a
nontrivial role of solar and galactic protons, is presented. The model is
described by the equation of fold catastrophe relative to increment of
temperature, where the variation of a solar insolation and cosmic rays are
control parameters. It is... | physics |
8,561 | Probabilistic temperature forecasting: a summary of our recent research results | physics.ao-ph | We summarise the main results from a number of our recent articles on the
subject of probabilistic temperature forecasting. | physics |
8,562 | Making use of the information in ensemble weather forecasts: comparing the end to end and full statistical modelling approaches | physics.ao-ph | We discuss how ensemble weather forecasts can be used, and highlight the
advantages and disadvantages of two particular methods. | physics |
8,563 | Probabilistic forecasting of temperature: comments on the Bayesian Model Averaging approach | physics.ao-ph | A specific implementation of Bayesian model averaging has recently been
suggested as a method for the calibration of ensemble temperature forecasts. We
point out the similarities between this new approach and an earlier method
known as kernel regression. We also argue that the Bayesian model averaging
method (as applie... | physics |
8,564 | Probabilistic forecasts of temperature: measuring the utility of the ensemble spread | physics.ao-ph | The spread of ensemble weather forecasts contains information about the
spread of possible future weather scenarios. But how much information does it
contain, and how useful is that information in predicting the probabilities of
future temperatures? One traditional answer to this question is to calculate
the spread-ski... | physics |
8,565 | Probabilistic temperature forecasting: a comparison of four spread-regression models | physics.ao-ph | Spread regression is an extension of linear regression that allows for the
inclusion of a predictor that contains information about the variance. It can
be used to take the information from a weather forecast ensemble and produce a
probabilistic prediction of future temperatures. There are a number of ways
that spread ... | physics |
8,566 | Observations and simulations of receiver-induced refractivity biases in GPS radio occultation | physics.ao-ph | This paper has been withdrawn. | physics |
8,567 | Global monitoring of tropospheric water vapor with GPS radio occultation aboard CHAMP | physics.ao-ph | The paper deals with application of GPS radio occultation (RO) measurements
aboard CHAMP for the retrieval of tropospheric water vapor profiles. The GPS RO
technique provides a powerful tool for atmospheric sounding which requires no
calibration, is not affected by clouds, aerosols or precipitation, and provides
an alm... | physics |
8,568 | Global Warming: some back-of-the-envelope calculations | physics.ao-ph | We do several simple calculations and measurements in an effort to gain
understanding of global warming and the carbon cycle. Some conclusions are
interesting: (i) There has been global warming since the end of the "little ice
age" around 1700. There is no statistically significant evidence of
acceleration of global wa... | physics |
8,569 | Statistical modelling of tropical cyclone tracks: a semi-parametric model for the mean trajectory | physics.ao-ph | We present a statistical model for the unconditional mean tracks of
hurricanes. Our model is a semi-parametric scheme that averages together
observed hurricane displacements. It has a single parameter that defines the
averaging length scale, and we derive the optimum value for this parameter
using a jackknife. The main... | physics |
8,570 | Influence of Coriolis force on propagation and reflection of long waves | physics.ao-ph | Influence of Coriolis force on propagation and reflection of the stimulated
long waves generated pulsing and harmonic concentrated sources is studied.
Geostrophic stream are found, is received asymptotics for transition mode. It
is established that in case of presence of rectilinear boundary as a result of
reflection K... | physics |
8,571 | Topographical scattering of waves: a spectral approach | physics.ao-ph | The topographical scattering of gravity waves is investigated using a
spectral energy balance equation that accounts for first order wave-bottom
Bragg scattering. This model represents the bottom topography and surface waves
with spectra, and evaluates a Bragg scattering source term that is
theoretically valid for smal... | physics |
8,572 | Statistical modelling of tropical cyclone tracks: a comparison of models for the variance of trajectories | physics.ao-ph | We describe results from the second stage of a project to build a statistical
model for hurricane tracks. In the first stage we modelled the unconditional
mean track. We now attempt to model the unconditional variance of fluctuations
around the mean. The variance models we describe use a semi-parametric nearest
neighbo... | physics |
8,573 | Improving on the empirical covariance matrix using truncated PCA with white noise residuals | physics.ao-ph | The empirical covariance matrix is not necessarily the best estimator for the
population covariance matrix: we describe a simple method which gives better
estimates in two examples. The method models the covariance matrix using
truncated PCA with white noise residuals. Jack-knife cross-validation is used
to find the tr... | physics |
8,574 | Year-ahead prediction of US landfalling hurricane numbers | physics.ao-ph | We present a simple method for the year-ahead prediction of the number of
hurricanes making landfall in the US. The method is based on averages of
historical annual hurricane numbers, and we perform a backtesting study to find
the length of averaging window that would have given the best predictions in
the past. | physics |
8,575 | Statistical modelling of tropical cyclone tracks: modelling the autocorrelation in track shape | physics.ao-ph | We describe results from the third stage of a project to build a statistical
model for hurricane tracks. In the first stage we modelled the unconditional
mean track. In the second stage we modelled the unconditional variance of
fluctuations around the mean. Now we address the question of how to model the
autocorrelatio... | physics |
8,576 | Revisiting the Local Scaling Hypothesis in Stably Stratified Atmospheric Boundary Layer Turbulence: an Integration of Field and Laboratory Measurements with Large-eddy Simulations | physics.ao-ph | The `local scaling' hypothesis, first introduced by Nieuwstadt two decades
ago, describes the turbulence structure of stable boundary layers in a very
succinct way and is an integral part of numerous local closure-based numerical
weather prediction models. However, the validity of this hypothesis under very
stable cond... | physics |
8,577 | Anomalous Gulf Heating and Hurricane Katrinas Rapid Intensification | physics.ao-ph | Global warming due to the increasing concentration of greenhouse gases has
become a great concern and has been linked to increased hurricane activity
associated with higher sea surface temperatures with conflicting views. Our
observational results based on long term trends of sea surface temperatures
reveal that the an... | physics |
8,578 | Exciton matter sustained by colossal dispersive interactions due to enhanced polarizability: Possible clue to ball lightning | physics.ao-ph | Recently Gilman has pointed out that the material state of a ball lightning
is both highly cohesive and flexible. He makes a specific proposal for a
cohesive state arising from (colossal) Van-der-Waals attraction between highly
polarizable Rydberg atoms produced under a linear lightning. We accept his
general suggestio... | physics |
8,579 | Current effects on scattering of surface gravity waves by bottom topography | physics.ao-ph | Scattering of random surface gravity waves by small amplitude topography in
the presence of a uniform current is investigated theoretically. This problem
is relevant to ocean waves propagation on shallow continental shelves where
tidal currents are often significant. A perturbation expansion of the wave
action to secon... | physics |
8,580 | Statistical modelling of tropical cyclone genesis: a non-parametric model for the annual distribution | physics.ao-ph | As part of a project to develop more accurate estimates of the risks due to
tropical cyclones, we describe a non-parametric method for the statistical
simulation of the location of tropical cyclone genesis. The method avoids the
use of arbitrary grid boxes, and the spatial smoothing of the historical data
is constructe... | physics |
8,581 | Seasonal Change of the Ozone Layer State over Yakutia | physics.ao-ph | The ozone layer state in the stratosphere over Yakutia depending on the year
time is considered. It is shown that the layer thickness is maximum in
February-March (450 Dobson's units) and it is minimum in July-September (300 -
350 DU). Measurements indicate that the ozone layer thickness was significantly
decreased in ... | physics |
8,582 | Subgrid-scale modeling of reacting scalar fluxes in large-eddy simulations of atmospheric boundary layers | physics.ao-ph | In large-eddy simulations of atmospheric boundary layer turbulence, the
lumped coefficient in the eddy-diffusion subgrid-scale (SGS) model is known to
depend on scale for the case of inert scalars. This scale dependence is
predominant near the surface. In this paper, a scale-dependent dynamic SGS
model for the turbulen... | physics |
8,583 | Forecasting Convective Downburst Potential Over The United States Great Plains | physics.ao-ph | A favorable environment for downbursts associated with deep convective storm
systems that occur over the central and eastern continental United States
includes strong static instability with large amounts of convective available
potential energy and the presence of a mid-tropospheric layer of dry air.
However, previous... | physics |
8,584 | A Study of a Cold-Season Downburst Event over the Oklahoma Panhandle | physics.ao-ph | This paper has been withdrawn by the author due to obsolete content. | physics |
8,585 | Statistical modelling of tropical cyclone tracks: modelling cyclone lysis | physics.ao-ph | We describe results from the fifth stage of a project to build a statistical
model of tropical cyclone tracks. The previous stages considered genesis and
the shape of tracks. We now consider in more detail how to represent the lysis
(death) of tropical cyclones. Improving the lysis model turns out to bring a
significan... | physics |
8,586 | Year-ahead prediction of US landfalling hurricane numbers: intense hurricanes | physics.ao-ph | We continue with our program to derive simple practical methods that can be
used to predict the number of US landfalling hurricanes a year in advance. We
repeat an earlier study, but for a slightly different definition landfalling
hurricanes, and for intense hurricanes only. We find that the averaging lengths
needed fo... | physics |
8,587 | Year ahead prediction of US landfalling hurricane numbers: the optimal combination of long and short baselines | physics.ao-ph | Annual levels of US landfalling hurricane activity averaged over the last 11
years (1995-2005) are higher than those averaged over the previous 95 years
(1900-1994). How, then, should we best predict hurricane activity rates for
next year? Based on the assumption that the higher rates will continue we use
an optimal co... | physics |
8,588 | Statistical modelling of tropical cyclone tracks: non-normal innovations | physics.ao-ph | We present results from the sixth stage of a project to build a statistical
hurricane model. Previous papers have described our modelling of the tracks,
genesis, and lysis of hurricanes. In our track model we have so far employed a
normal distribution for the residuals when computing innovations, even though
we have de... | physics |
8,589 | On Possibility of Electromagnetic Nature of Atmospheric Intensive Vortices Generation | physics.ao-ph | Our goal is to find out possible appearance of rotational motion in the
atmosphere, created by a lightning. A positive solution of this question, in
the end, leads to a necessity of accepting that processes of birth and
annihilation of electron-positron pairs take place in the leader head of
lightning channel. Under th... | physics |
8,590 | Comments on "Increasing destructiveness of tropical cyclones over the past 30 years" by Kerry Emanuel, Nature, 31 July 2005, Vol. 436, pp. 686-688 | physics.ao-ph | The near universal references to the above paper by most of the major US
media outlets and blogs since Katrina and Rita made US landfall requires a
response from a few of us who study hurricanes. Having been involved with
hurricane research and forecasting for nearly 50 years, I feel I have an
obligation to offer comme... | physics |
8,591 | Comments by William M. Gray (Colorado State University) on the recently published paper in Science by Webster et al., titled "Changes in tropical cyclone number, duration, and intensity in a warming environment." (September 2005, Vol. 309, pp. 1844-1846, www.sciencemag.org) | physics.ao-ph | Recent US major landfalling hurricanes Katrina and Rita and last year's four
U.S. landfalling major hurricanes have spawned an abundance of questions
concerning the role that global warming might be playing in these events. This
idea has been given added credence by the September 2005 Science paper of
Webster, Holland,... | physics |
8,592 | A Study of a Dryline Convective Downburst | physics.ao-ph | During the afternoon of 15 June 2005, convective storms developed along and
west of the dryline over eastern Colorado and New Mexico. One such storm
tracked eastward into Cimarron County, Oklahoma and produced a strong downburst
at Kenton. The dryline, as it tracked eastward over the western Oklahoma
Panhandle, establi... | physics |
8,593 | Computationally-efficient Expressions for the Collision Efficiency Between Electrically Charged Aerosol Particles and Cloud Droplets | physics.ao-ph | A multifactor parameterization is described to permit the efficient
calculation of collision efficiency (E) between electrically charged aerosol
particles and neutral cloud droplets in numerical cloud and climate models. The
four parameter representation summarizes the results obtained from a detailed
microphysical mod... | physics |
8,594 | The Role of Downward Momentum Transport in the Generation of Convective Downbursts | physics.ao-ph | A downburst index has been developed to assess the magnitude of convective
downbursts associated with heavy precipitation-producing (HP) convective
systems. The index, designed for use during the warm season over the central
and eastern continental United States, is composed of relevant parameters that
represent the si... | physics |
8,595 | Aerosol Characteristics at a High Altitude Location in Central Himalayas: Optical Properties and Radiative Forcing | physics.ao-ph | Collocated measurements of the mass concentrations of aerosol black carbon
(BC) and composite aerosols near the surface were carried out along with
spectral aerosol optical depths (AODs) from a high altitude station, Manora
Peak in Central Himalayas, during a comprehensive aerosol field campaign in
December 2004. Despi... | physics |
8,596 | An explanation for the lack of trend in the hurricane frequency | physics.ao-ph | The proposition that the tropical cyclogenesis increases with the size of the
warm pool, the area enclosed by the 26C SST isotherm, is tested by comparing
the seasonal variation of the warm pool area with the seasonality of the number
of tropical cyclones. A non-linear relationship of high statistical
significance is f... | physics |
8,597 | Electrical Behavior of Downburst-Producing Convective Storms over the Western United States | physics.ao-ph | A great body of research literature pertaining to microburst generation in
convective storms has focused on thermodynamic factors of the pre-convective
environment as well as storm morphology as observed by radar imagery. Derived
products based on GOES sounder data have been found to be especially useful in
the study o... | physics |
8,598 | A Qualitative Description of Boundary Layer Wind Speed Records | physics.ao-ph | The complexity of the atmosphere endows it with the property of turbulence by
virtue of which, wind speed variations in the atmospheric boundary layer (ABL)
exhibit highly irregular fluctuations that persist over a wide range of
temporal and spatial scales. Despite the large and significant body of work on
microscale t... | physics |
8,599 | Tropical Cyclone Forecasting Applications of the GOES WMSI | physics.ao-ph | The Geostationary Operational Environmental Satellite (GOES) sounder-derived
Wet Microburst Severity Index (WMSI) was originally developed and implemented
to assess the potential magnitude of convective downbursts over the central and
eastern continental United States. The WMSI algorithm incorporates convective
availab... | physics |
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