bluuebunny/crossref_metadata_2025_split huggingface dataset:
A PRELIMINARY ANALYSIS OF ATMOSPHERIC DENSITIES FROM METEOR DECELERATIONS FOR SOLAR, LUNAR AND YEARLY OSCILLATIONS
Authors: Jacchia Luigi G. 
Published: August 2010

Abstract
Upper-atmosphere densities derived from photographic meteor decelerations were analyzed to probe the existence of detectable oscillations with periods corresponding to solar and lunar tides (and half-periods) and seasonal variations. Extensive fragmentation in meteors adds considerable difficulty to the analysis and makes empirical corrections necessary. The mean height of the analyzed meteors is 91.8 kilometers. A seasonal variation with an amplitude of 15 per cent of the mean density barely emerges from its probable error by a factor of two; tidal oscillations, if present, are masked by observational scatter and could not exceed 10 per cent of the mean density.
AN APPROACH TO QUANTITATIVE PRECIPITATION FORECASTING
Authors: Estoque M. A. 
Published: August 2010

Abstract
A quantitative method of predicting precipitation due to large-scale vertical motions is described. A two-level prediction model is applied at the 1000- and 500-millibar pressure levels. Solutions are obtained by graphical procedure which enables one to obtain a 24-hour forecast in about two hours for an area comparable to the size of the North American continent. Tests on ten cases of major cyclone developments show some success.
MEASUREMENTS OF CLOUD DROP-SIZE DISTRIBUTIONS
Authors: Eldridge Ralph G. 
Published: August 2010

Abstract
Through the analysis of infrared transmittance of a natural cloud, its drop-size distribution can be inferred. This technique has been used to measure and analyze ten cloud situations on Mount Washington. These clouds show drop-size distributions that are bimodal in character. In all the distributions, a large number of small droplets is inferred. To test the synthesized distributions in another region of the spectrum, the visual range was computed. This determination of the visual range is in agreement with the observed visibilities.
The Numerical Simulation of Airflow and Dispersion in Three-Dimensional Atmospheric Recirculation Zones
Authors: Dawson Paul , Stock David E. , Lamb Brian 
Published: August 2010

AbstractA three-dimensional, nonhydrostatic numerical code using the two-equation turbulence closure was developed to model the atmospheric transport and diffusion of pollutants over buildings and a three-dimensional hill. The standard engineering two-equation, first-order turbulence closure was modified to account for surface layer effects and the reduced production of dissipation in the region above the surface layer found in an atmospheric boundary layer.The computations for the dispersion of a building rooftop release showed good agreement with wind tunnel measurements, except when very close to the ground. The transport and dispersion of a plume over a 300-m conical hill, Steptoe Butte, was also simulated. The computations are compared with near ground-level field measurements.
Comment on “Persistence and Recurrence Probabilities of Cloud-Free and Cloudy Lines of Sight through the Atmosphere”
Authors: Medler Charles L. , MacNichol Kenneth B. 
Published: August 2010

AbstractAlthough published some time ago, the subject paper represents a well-known resource for modeling and assessing cloud impacts on land-based and air-based electro-optical systems. The Lund dataset, derived from whole-sky photographs taken during the summer months at Columbia, Missouri, remains unique and valuable and has been used in assembling critical cloud-free line-of-sight models. In Lund's paper, cloud-free and cloudy persistence and recurrence probabilities, plotted versus elapsed time interval for each of 11 categories of fractional sky cover, are provided. The purpose of this comment is to provide an expression that properly combines these probabilities to produce persistence and recurrence probabilities irrespective of sky cover category (i.e., probabilities that are valid when the sky cover is not known a priori). Lund presented a “matrix model” for representing these probabilities. Lund's matrix model does not represent the average recurrence or persistence probability over all sky cover conditions, as is shown in the Appendix.
Microwave Simulations of a Tropical Rainfall System with a Three-Dimensional Cloud Model
Authors: Adler Robert F. , Yeh Hwa-Young M. , Prasad N. , Tao Wei-Kuo , Simpson Joanne 
Published: August 2010

AbstractA three-dimensional cloud model-microwave radiative transfer model combination is used to study the relations among the precipitation and other microphysical characteristics of a tropical oceanic squall line and the upwelling radiance at pertinent microwave frequencies. Complex brightness temperature-rain rate relations are evident at the full horizontal resolution (1.5 km) of the models, with spatial avenging producing smoother, shifted relations, in most cases. Nonprecipitating cloud water is shown to be important in understanding the resulting distribution of brightness temperature. At the mature stage, convective portions of the cloud system are shown to produce different brightness temperature relations than the stratiform portion, primarily related to the distribution of cloud water. The evolution of the convective system from a small convective complex through its mature stage and the beginning of its dissipation also is shown to result in a variation of brightness temperature-rain relations, related to the distribution of cloud water and the evolution of ice in the precipitating system. The results of the study paint to the need to take into account the evolution of nonprecipitating cloud water and precipitation-sized ice in the retrieval of rain team from microwave space observations. This effect is evident for both the life cycle of individual convective elements and the life cycle of the convective system as a whole.
Information Content of AVHRR Channels 4 and 5 with Respect to the Effective Radius of Cirrus Cloud Particles
Authors: Parol F. , Buriez J. C. , Brogniez G. , Fouquart Y. 
Published: August 2010

AbstractThis paper investigates the important difference in the relationship between brightness temperatures between the 11-μm and the 12-μn AVHRR data and the microphysical properties of the semitransparent cirrus clouds. In the nonscattering approximation, the emittance for channels 4 and 5 are related through the absorption coefficient ratio that is the key parameter giving access to the size of cloud particles. The observed mean value of this parameter corresponds to effective radius of 18 μm for polydisperse spheres and 12 μm for polydisperse infinitely long ice cylinders. Taking the multiple scattering into account, the brightness temperature difference enhances much more for cylinders than for spheres owing to the fact that the forward peak of scattering is less large for cylinders. To obtain the size of cloud particles, the method developed in the nonscattering case is still applicable if one makes use of the effective emittance that implicitly includes the effects of mattering. Thus, an effective absorption coefficient ratio is defined and we derive a direct relationship between this ratio and the optical properties of the cloud particles. The mean value of the effective absorption coefficient ratio corresponds to ice spheres of effective radius of 26 μm or a bit less in the case of water spheres (supercooled droplets), but no agreement can be obtained for fully randomly oriented cylinders.
A New Parameterization Scheme for Shortwave Radiative Properties of Water Clouds
Authors: Zhang Guotong , Xu Lisheng , Chen Hongbin 
Published: August 2010

Abstract
A new parameterization scheme for the shortwave radiative properties of water clouds is presented, using versatile cloud drop size distributions ( DSDs). As for single-scattering properties, a new parameterization for cloud optical thickness is proposed by using the separation of the dependence of r on the total number of theDSDs, the cloud thickness, and the liquid water content, combined with equivalent radius. The cloud bulk radiative properties are obtained from the delta-Eddington approximation for our cloud models. It is shown that the flux reflectivity, transmissivity, and absorptivity are uniquely fitted by a dimensionless parameter X or the cloud optical thickness 7. The parameterization is compared with other schemes. The features and potential use of the scheme are discussed.
Assessment of Seeding Effects in Snowpack Augmentation Programs: Ice Nucleation and Scavenging of Seeding Aerosols
Authors: Warburton J. A. , Young L. G. , Stone R. H. 
Published: August 2010

AbstractTrace chemical analysis techniques have been used in a series of cloud-seeding experiments in the central Sierra Nevada with the ultimate purpose of distinguishing whether the submicron-sized aerosol particles used for seeding are removed by nucleation or by scavenging in snowfall. The research programs used submicron-sized seeding aerosols with different nucleating characteristics. When winter storms were seeded with silver iodide in the Lake Tahoe and Lake Almanor watersheds, positive correlations were observed between silver concentrations and precipitation amounts in both catchment areas.This is considered to be evidence that the AgI aerosols are not being removed in the snowfall entirely by scavenging processes. When two separate aerosols of silver iodide and indium sesquioxide were released simultaneously from the same ground locations during winter snowstorms in the Lake Almanor watershed, it was found that considerably more of the ice-nucleating aerosol particles (AgI) were removed by the snowfall than the non-ice-nucleating ones (In203). Under the experimental conditions employed, scavenging alone of the two aerosols would lead to a chemical ratio of Ag:In in the snowfall of 0.83:l. Ratios as high as 17.2:l were observed, the mean ratio being 4: I. These results are considered to be evidence of the removal of substantial numbers of the AgI aerosol particles through direct nucleation of ice crystals.
Numerical Simulation of a Rain Shower Affected by Waste Energy Released from a Cooling Tower Complex in a Calm Environment
Authors: Guan S. , Reuter G. W. 
Published: August 2010

Abstract
An axisymmetric cloud model is used to investigate the evolution of convective cells and associated rain showers that develop due to the sensible and latent heat released into a calm atmosphere from an industrial cooling complex. The simulated convection is in fair agreement with observations for a particular cloud developingover a large cooling system. Sensitivity experiments were run for two different soundings to quantify how the convection and rainfall depend on the magnitude of the waste energy loss, the area of the source region, and other parameters. The major findings were the following:1 ) Without a sustained waste heat input the model convection ceased. The model convection became progressively more intense and developed more rain when the rate of total waste energy heat released from thepower station was increased. Doubling the total waste energy amount from its control case value caused a 15-fold increase in 3-h rainfall values. However, reducing the control case value of total waste energy release by 20% led to much weaker convection without rain.2) The triggering of cumulus clouds was reduced when the waste energy was released in terms of latent heat rather than sensible heat. As the relative contribution of sensible heat increased, so did the intensity of the circulation and the rainfall.3) The cloud formation depended on the area of the heat source: a wider source tended to delay and to weaken the convection. Specifically, when the area was doubled the simulated cloud appeared 2.5 min laterand the total accumulated rain after 3 h was reduced by 88%. Moreover, the maximum total kinetic energy was reduced by 26%.4) The model results were only slightly sensitive to the radial distribution of the sensible and latent heatfluxes within the source region.
Automated Quality Control Procedure for the "Water Equivalent of Snow on the Ground" Measurement
Authors: Schmidlin Thomas W. , Wilks Daniel S. , McKay Megan , Cember Richard P. 
Published: August 2010

Abstract
Snow water equivalent (SWE) has been measured daily by the United States National Weather Service since 1952, whenever snow depth is 2 in. (5 cm) or greater. These data are used to develop design snow loads for buildings, for hydrological forecasting, and as an indicator of climate change. To date they have not been subjected comprehensively to quality control. An automated quality control procedure for these data is developed here, which checks daily SWE values for common data entry errors, values beyond reasonable limits, and consistency with daily precipitation and estimated melt. Potential effects of drifting in high winds and of the intrinsic microscale variability of SWE are also considered. An SWE measurement is declared suspicious if a sufficient discrepancy is found with respect to the expected SWE. Data values flagged as potential errors are checked manually. Results of applying the procedure to available SWE data from the northeastern UnitedStates are also summarized.
Development and Testing of a Surface Flux and Planetary Boundary Layer Model for Application in Mesoscale Models
Authors: Pleim Jonathan E. , Xiu Aijun 
Published: August 2010

AbstractAlthough the development of soil, vegetation, and atmosphere interaction models has been driven primarily by the need for accurate simulations of long-term energy and moisture budgets in global climate models, the importance of these processes at smaller scales for short-term numerical weather prediction and air quality studies is becoming more appreciated. Planetary boundary layer (PBL) development is highly dependent on the partitioning of the available net radiation into sensible and latent heat fluxes. Therefore, adequate treatmentof surface properties such as soil moisture and vegetation characteristics is essential for accurate simulation of PBL development, convective and low-level cloud processes, and the temperature and humidity of boundary layer air. In this paper, the development ofa simple coupled surface and PBL model, which is planned for incorporation into the Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM4/5), is described. The soil-vegetation model is based on a simple force-restore algorithm with explicit soil moisture and evapotranspiration. The PBL model is a hybrid of nonlocal closure for convective conditions and eddy diffusion for all other conditions. A one-dimensional version of the model has been applied to several case studies from field experiments in both dry desert-like conditions (Wangara) and moist vegetated conditions(First International Satellite Land Surface Climatology Project Field Experiment) to demonstrate the model's ability to realistically simulate surface fluxes as well as PBL development. This new surface-PBL model is currently being incorporated into the MM4-MM5 system.
Cloud Model-Based Simulation of Spaceborne Radar Observations
Authors: Yeh H-Y. M. , Prasad N. , Meneghini R. , Tao W-K. , Jones J. A. , Adler R. F. 
Published: August 2010

Abstract
Simulations of observations from potential spaceborne radars are made based on storm structure generated from the three-dimensional (3D) Goddard cumulus ensemble model simulation of an intense overland convective system. Five frequencies of 3, 10, 14, 35, and 95 GHz are discussed, but the Tropical Rainfall Measuring Mission precipitation radar sensor frequency ( 14 GHz) is the focus of this study. Radar reflectivities and their attenuation in various atmospheric conditions are studied in this simulation. With the attenuation from cloud and precipitation in the estimation of reflectivity factor (dBZ), the reflectivities in the lower atmosphere in the convective coresare significantly reduced. With spatial resolution of 4 km X 4 km, attenuation at 14 GHz may cause as large as a 20-dBZ difference between the simulated measurements of the peak (Zmp) and near-surface reflectivity (Zmp) in the most intense convective region. The Zmp occurs at various altitudes depending on the hydrometeor concentrations and their vertical distribution. Despite the significant attenuation in the intense cores, the presence of the rain maximum is easily detected by using information of Zmp. In the stratiform region, the attenuation is quite limited (usually less than 5 dBZ), and the reduction of reflectivity is mostly related to the actual vertical structure of cloud distribution. Since Zmp suffers severe attenuation and tends to underestimate surface rainfall intensity in convective regions, Zmp can be more representative for rainfall retrieval in the lower atmosphere in these regions. In the stratiform region where attenuation is negligible, however, Zmp tends to overestimate surface rainfall and Zmp is more appropriate for rainfall retrieval. A hybrid technique using a weight between the two rain intensities is testedand found potentially useful for future applications. The estimated surface rain-rate map based on this hybrid approach captures many of the details of the cloud model rain field but still slightly underestimates the rain-rate maximum.
Improvements of an Ice-Phase Microphysics Parameterization for Use in Numerical Simulations of Tropical Convection
Authors: Krueger Steven K. , Fu Qiang , Liou K. N. , Chin Hung-Neng S. 
Published: August 2010

Abstract
It is important to properly simulate the extent and ice water content of tropical anvil clouds in numerical models that explicitly include cloud formation because of the significant effects that these clouds have on the radiation budget. For this reason, a commonly used bulk ice-phase microphysics parameterization was modified to more realistically simulate some of the microphysical processes that occur in tropical anvil clouds. Cloud ice growth by the Bergeron process and the associated formation of snow were revised. The characteristics of graupel were also modified in accord with a previous study. Numerical simulations of a tropical squall line demonstrate that the amount of cloud ice and the extent of anvil clouds are increased to more realistic values by the first two changes.
Turbulent Mixing in Stably Stratified Shear Flows
Authors: Schumann U. , Gerz T. 
Published: August 2010

Abstract
Vertical mixing of momentum and heat is investigated in turbulent stratified shear flows. It is assumed that the flow has uniform shear and stratification with homogeneous turbulence and that an equilibrium is reached between kinetic and potential energy without gravity wave oscillations. A simple model is derived to estimate vertical diffusivities for Richardson numbers in between 0 and about 1. The model is based on the budgets of kinetic and potential energy and assumes a linear relationship between dissipation, shear, and vertical velocity variance for closure. Scalar fluctuations are related to shear or buoyancy frequency depending on the Richardson number. The turbulent Prandtl number and the growth rate of kinetic energy are specified as functions of this number. Model coefficients are determined mainly from laboratory measurements. Data from large-eddy simulations are used to determine the "stationary" Richardson number with balanced shear production, dissipation, and buoyancy terms. The results of the model are compared with data from laboratory experiments in air or saltwater, with measurements in the atmospheric boundary layer and in the stable troposphere, and with results from the numerical simulations. The model interpolates the observations within the scatter of the data. Theanalysis shows intrinsic relationships between several mixing parameters.
Description of Wind Field Dynamic Patterns in a Valley and Their Relation to Mesoscale and Synoptic-Scale Meteorological Situations
Authors: Guardans R. , Palomino I. 
Published: August 2010

Abstract
A large set of hourly meteorological data from seven towers deployed in Montesina Valley (Cordoba, Spain) is studied in relation to the prevailing synoptic situation. The complete collection of daily synoptic maps for 1985-90 has been classified in seven basic weather patterns. First-order transition probabilities and weatherpattern persistences have been calculated for each of the patterns. The behavior of the local valley wind field is described as a function of the synoptic patterns. The work reported here, based on observations of the characteristic time and space patterns of flow in the valley under different synoptic conditions, has made it possible to obtain a set of empirical rules and regression functions to produce forecasts of the local wind field as a function of the synoptic situation and the hour of the day to be used in the emergency plans. The result of this work is currently being implemented in an atmospheric dispersion module of an expert system that will be used as a tool to predict the evolution of accidental and routine hazardous emissions to the atmosphere in complex terrain such as valleys and coastal areas.
Aggregation of Selected Three-Day Periods to Estimate Annual and Seasonal Wet Deposition Totals for Sulfate, Nitrate, and Acidity. Part I: A Synoptic and Chemical Climatology for Eastern North America
Authors: Brook Jeffrey R. , Samson Perry J. , Sillman Sanford 
Published: August 2010

Abstract
Running 3-day periods from 1979 to 1985 were categorised into one of 20 meteorological categories. These categories were developed through the cluster analysis of 3-day progressions of 85-kPa wind flow over eastern North America. The purpose for developing the categories was to identify recurring atmospheric transport patterns that were associated with differing amounts of wet sulfate (SO2−4) and nitrate (NO−3) deposition at a variety of locations in eastern North America. Identification of these patterns was necessary to facilitate the selection of time periods for simulation by the Regional Acid Deposition Model and in the development of a method for estimating long-term acidic deposition over eastern North America from a limited number of model runs. The effectiveness of this method (referred to as the aggregation method) was expected to be dependent on the ability of the categories to separate structure in wet deposition patterns. This paper describes the determination of the 20 meteorological categories and demonstrates that there were differences in their meteorological and chemical behavior and in their frequency of occurrence. Observations of precipitation and wet SO2−4 and NO−3 deposition from 22 sites in eastern North America and multiple regression models were used to demonstrate that there were statistically significant differences in deposition among categories and that knowledge of meteorological category explained some of the variation in wet deposition. The best statistical correlation, which was based upon precipitation amount, time of year, and meteorological category, explained 35%&#x96;83% (28%&#x96; 76%) of the observed variation in wet SO2−4 (NO−3) deposition depending on location. On average, across all sites and for both SO2−4 and NO−3, knowledge of category accounted for about 4% of the variation. The minimum amount explained by category was 1% and the maximum was 13%.