bluuebunny/crossref_metadata_2025_split huggingface dataset:
GRAPHICAL INTEGRATIONS OF A TWO-LEVEL MODEL
Authors: Estoque M. A. 
Published: August 2010

Abstract
A prediction model representing a slight modification of a previous model (Estoque, 1956a) is presented. The prediction equations were integrated graphically to produce 24-hour 1000- and 500-millibar forecasts for the month of January 1953. The results indicate that the method may be of considerable value in routine forecasting, particularly in regions where orographic influences are no great concern.
CLOUD PHOTOGRAMMETRY WITH GROUND-LOCATED K-17 AERIAL CAMERAS
Authors: Kassander A. Richard , Sims Lee L. 
Published: August 2010

Abstract
A technique is presented in which a pair of ground-located K-17 aerial cameras is used on a 1.30-milebaseline to determine cloud ranges to 1-mi accuracy at 40 mi, and cloud-height measurements to within 500 feet at this range. Details of the power supply, vacuum supply, and camera-synchronization requirements are discussed, as well as methods used in analysis. In particular, a detailed discussion is given of the theoretical and practical errors encountered in such a photogrammetric technique.
ON THE INTEGRATION OF THE HEAT-CONDUCTION EQUATION WITH PERIODIC VARIATION OF TEMPERATURE
Authors: de Vries D. A. 
Published: August 2010

Abstract
An integration of the Fourier equation of heat conduction in a semi-infinite medium (air) is presented for the case where the thermal (or eddy) diffusivity varies with height, assuming a harmonic variation of temperature with time. Special attention is paid to the case where the medium consists of an arbitrary number of layers in each of which the diffusivity is represented by a different function of height.
Application of these methods resolves some of the difficulties encountered in explaining the observed variation of amplitude and phase of the temperature wave with height. It is concluded that —although theoretically possible —it is not feasible in practice to evaluate the diffusivity from an analysis of observations of this type, and that some results of previous attempts to do so are largely in error.
Relations between the waves of temperature and heat flux near the surface are briefly discussed. It is shown that for the diurnal waves these depend, inter alia, on the diffusivity values up to a height of the order of 1000 meters.
Accuracy of Satellite Land Surface Reflectance Determination
Authors: Arino O. , Dedieu G. , Deschamps P. Y. 
Published: August 2010

AbstractAn accuracy budget of the surface reflectance determination from Meteosat geostationary satellite data is performed. Error analysis allows identification of three main problems: calibration uncertainty of the Meteosat instrument, atmospheric corrections, and surface effects (spectral and directional). Calibration accuracy is 10%, leading to a 10% relative uncertainty on reflectance. Spectral effects of the surface lead to a maximum bias of 0.01 for a vegetated surface as sensed by Meteosat, while directional effects can lead to a bias of 0.035 between two measurements taken at two different sun zenith and azimuth angles at the same view angle over savannas. The maximum error due to the atmosphere is estimated to be of the order of 0.03 in reflectance for a surface reflectance of 0.40 and 0.01 for, a surface reflectance of 0.10. Validation with in situ measurement is within the expected error over savanna. But the difference is still high over the southwest France site of HAPEX-MOBILHY, certainly due to the joint spectral and directional errors. Comparisons with surface albedo maps from literature show the same spatial and spatial evolutions with a better spatial and temporal determination in our results.
Comparison of Ice-Phase Microphysical Parameterization Schemes Using Numerical Simulations of Tropical Convection
Authors: McCumber Michale , Tao Wei-Kuo , Simpson Joanne , Penc Richard , Soong Su-Tzai 
Published: August 2010

AbstractA numerical cloud model is used to evaluate the performance of several ice parameterizations. Results from simulations using these schemes are contrasted with each other, with an ice-free control simulation, and with observations to determine to what extent ice physics affect the realism of these results. Two different types of tropical convection are simulated. Tropical squall-type systems are simulated in two dimensions so that a large domain can be used to incorporate a complete anvil. Nonsquall-type convective lines are simulated in three dimensions owing to their smaller horizontal scale.The inclusion of ice processes enhances the agreement of the simulated convection with some features of observed convection, including the proportion of surface rainfall in the anvil region, and the intensity and structure of the radar brightband near the melting level in the anvil. In the context of our experimental design, the use of three ice classes produces better results than two ice classes or ice-free conditions, and for the tropical cumuli, the optimal mix of the bulk ice hydrometeors is cloud ice-snow-graupel. We infer from our modeling results that application of bulk ice microphysics in cloud models might be case specific, which is a significant limitation. This can have serious ramifications for microwave interpretation of cloud microphysical properties. Generalization of ice processes may require a larger number of ice categories than we have evaluated and/or the prediction of hydrometeor concentrations or particle-size spectra.
Topographic and Atmospheric Influences on Precipitation Variability over a Mountainous Watershed
Authors: Johnson Gregory L. , Hanson Clayton L. 
Published: August 2010

Abstract
Using rotated principal component analysis (PCA), unique, orthogonal spatial patterns of daily and monthlyprecipitation on a well-instrumented, mountainous watershed in Idaho are examined for their relationship totopography, geographic location, and atmospheric variability. Precipitation pattern and homogeneous precipitationregion differences between daily and monthly timescales and between winter and summer Seasons were identifiedusing the rotated PCA procedure. In general, monthly data produced regional boundaries more closely alignedwith topography, reflecting the integration of many storm events on monthly timescales. Spatial fields, derivedfrom mapping rotated component loadings at 46 precipitation stations on a 234-kmz watershed, were found tobe highly correlated with topography and geographic location. The eight-year time series of the components forspecific watershed regions were found to be moderately related to linear combinations of meteorological variablesderived from a single radiosonde station approximately 50 km from the waterhed. This would indicate thepotential usefulness of data from a single location, such as a general circulation model grid point, to provideclues about spatial pattern changes and regional precipitation fluctuations even on a small watershed, if sufficientinformation about local climate (i.e., topographic influences) is first established.
Rain-Rate Estimation in the Presence of Hail Using S-Band Specific Differential Phase and Other Radar Parameters
Authors: Aydin K. , Bringi V. N. , Liu L. 
Published: August 2010

Abstract
Multiparameter radar measurements were made during a heavy rainfall event accompanied by hail in Colorado. Rainfall rates R and accumulation Σ for this event were estimated using S-band specific differential phase KDP, reflectivity factor ZH, and X-band specific attenuation AH3. These estimates were compared with measurements from a ground-based rain gauge. Both R&#x96;KDP and R&#x96;AH3 relations were in good agreement with the rain gauge data, that is, less than 10% difference in the rainfall accumulations. The R&#x96;Z relation produced similar results only when ZH was truncated at 55 dBZ. This study demonstrates the potential of KDP for estimating rainfall rates in severe storms that may have rain-hail mixtures.
Removal of the Solar Component in AVHRR 3.7-µm Radiances for the Retrieval of Cirrus Cloud Parameters
Authors: Rao N. X. , Ou S. C. , Liou K. N. 
Published: August 2010

Abstract
A numerical scheme has been developed to remove the solar component in the Advanced Very High Resolution Radiometer (AVHRR) 3.7-µm channel for the retrieval of cirrus parameters during daytime. This method uses a number of prescribed threshold values for AVHRR channels 1 (0.63 µm), 2 (0.8 µm), 3 (3.7 µm), 4 (10.9 µm), and 5 (12 µm) to separate clear and cloudy pixels. A look-up table relating channels 1 and 3 solar reflectances is subsequently constructed based on the prescribed mean effective ice crystal sizes and satellite geometric parameters. An adding&#x96;doubling radiative transfer program has been used to generate numerical values in the construction of the look-up table. Removal of the channel 3 solar component is accomplished by using the look-up table and the measured channel 1 reflectance. The cloud retrieval scheme described in Ou et al. has been modified in connection with the removal program. The authors have applied the removal&#x96;retrieval scheme to the AVHRR global area coverage daytime data, collected during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment cirrus intensive field observation (FIRE IFO) at 2100 UTC 28 October 1986 over the Wisconsin area. Distributions of the retrieved cloud heights and optical depths are comparable to those determined from Geostationary Operational Environmental Satellite visible and IR channels data reported by Minnis et al. Morwver, verifications of the retrieved cirrus temperature and height against lidar data have been carried out using results reported from three FIRE IFO nations. The retrieved cloud heights are within 0.5 km of the measured lidar values.
Quantitative Estimates of Cloudiness over the Gulf Stream Locale Using GOES VAS Observations
Authors: Alliss Randall J. , Raman Sethu 
Published: August 2010

Abstract
Fields of cloudiness derived from the Geostationary Operational Environmental Satellite VISSR (Visible&#x96;Infrared Spin Scan Radiometer) Atmospheric Sounder are analyzed over the Gulf Stream locale (GSL) to investigate seasonal and geographical variations. The GSL in this study is defined as the region bounded from 31° to 38°N and 82° to 66°W. This region covers an area that includes the United States mid-Atlantic coast states, the Gulf Stream, and portions of the Sargasso Sea. Clouds over the GSL are found approximately three-quarters of the time between 1985 and 1993. However, large seasonal variations in the frequency of cloudiness exist. These seasonal variations show a distinct relationship to gradients in sea surface temperature (SST). For example, during winter when large SST gradients are present, large gradients in cloudiness are found. Clouds are observed least often during summer over the ocean portion of the GSL. This minimum coincides with an increase in atmospheric stability due to large-scale subsidence. Cloudiness is also found over the GSL in response to mesoscale convergence areas induced by sea surface temperature gradients. Geographical variations in cloudiness are found to be related to the meteorology of the region. During periods of cold-air advection, which are found most frequently in winter, clouds are found less often between the coastline and the core of the Gulf Stream and more often over the Sargasso Sea. During cyclogenesis, large cloud shields often develop and cover the entire domain.
Satellite estimates of cloudiness are found to be least reliable over land at night during the cold months. In these situations, the cloud retrieval algorithm often mistakes clear sky for low clouds. Satellite-derived cloudiness over land is compared with daytime surface observations of cloudiness. Results indicate that retrieved cloudiness agrees well with surface observations. Relative humidity fields taken from global analyses are compared with satellite cloud heights at three levels in the atmosphere. Cloudiness observed at these levels is found at relative humidities in the 75%&#x96;100% range but is also observed at humidities as low as 26%.
The Influence of Forests on Atmospheric Heating during the Snowmelt Season
Authors: Yamazaki Takeshi 
Published: August 2010

Abstract
Atmospheric heating during the snowmelt season has been studied by means of data analysis and numerical model experiments. As a result of the data analysis, it was shown that in some examples the daytime air temperature rose above 0°C, even if the ground surface was covered by snow. Moreover, it was found that the number of days when the daytime air temperature rose above 0°C was large when the duration of sunshine increased. However, the increase was not related to the wind speed. Therefore, the air temperature over snow cover increases during the daytime if the sunshine is strong even under calm conditions (weak advection). On the other hand, the following result was obtained with the use of a local circulation model combined with a canopy heat balance model. The atmosphere was heated over the plains if forested areas existed around the plains, even if the plains surfaces were covered by snow without forests. An upward sensible heat flux was supplied from the forest canopy, resulting in atmospheric heating. It was concluded that the existence of forests was one of the main causes of atmospheric heating during the snowmelt season.
Trajectories for Saharan Dust Transported to Barbados Using Stokes's Law to Describe Gravitational Settling
Authors: Ellis W. G. , Merrill J. T. 
Published: August 2010

Abstract
Atmospheric chemistry programs often make use of retrospective back trajectories to determine the source regions of substances sampled at a particular site. Isentropic trajectories, which depict motion on hypothetical surfaces of constant potential temperature, have been used as part of the Atmosphere/Ocean Chemistry Experiment to understand the sources of aerosols and gases sampled over the North Atlantic Ocean. However, isentropic trajectories typically do not adequately describe the transport of mineral aerosol, for example, from the Sahara Desert to Barbados. Boundary layer trajectories indicated that northern Africa was the source region for 12% of the samples with significant aluminum (Al) concentrations (&gt; 1.0 µg m−3). Upper-level isentropic trajectories (310 and 315 K) indicated transport from northern Africa for approximately half of the samples with Al concentrations greater than 1.0 µg m−3. However, at the location of the sampling site, the upper-level trajectories were well above the boundary layer, where the mineral aerosol samples were collected. Stokes's law was used in the calculation of nonisentropic trajectories that incorporated the gravitational settling of aerosol particles. These trajectories, which began in the boundary layer, were calculated from a combination of lower-level and upper-level wind fields, and more accurately represented the wind fields that transported Saharan dust to Barbados. The Stokes's law trajectories for 4-µm aerosol particles reached a maximum in transport from northern Africa during the summer, which was also when the highest Al concentrations were observed. The Stokes's law trajectories for 4-µm aerosol particles indicated northern Africa as the source region for 55% of the high Al samples, while the equivalent value was only 9% for the 2-µm aerosols trajectories. Dust samples collected at Barbados have a smaller mean radius than the calculation required, indicating that other vertical motions are important during transport in addition to gravitational settling. However, up to 20% of the dust sampled at Barbados is in the size range used (4 µm).
Meteorology and Forest Fires: Conditions for Ignition and Conditions for Development
Authors: Martín L. Delgado , Diez A. García , Soriano L. Rivas , Diez E. L. García 
Published: August 2010

Abstract
Following the theoretical model proposed in previous papers in which four types of days and their associated fire risk (daily fire risk, DFR) were defined for each size of fire, the authors conclude that the meteorological conditions that favor the generation of fires must be similar to those that are favorable to their development. In a study of burned areas, comparative results with previous works are obtained, and the parameters DFR and NDFR (normalized DFR) are proven to be in agreement with their previously assigned physical meaning. The development rather than the ignition of forest fires is better described using the DFR and NDFR parameters.
Longwave Radiation on Snow-Covered Mountainous Surfaces
Authors: Plüss Christian , Ohmura Atsumu 
Published: August 2010

Abstract
Longwave radiation in snow-covered alpine environments was investigated based on LOWTRAN7 calculations. The irradiance from the sky and from the surrounding topography were determined separately in order to detect the influence of the topography on longwave radiation balance. Sensitivity studies showed that the irradiance from the surrounding terrain is determined primarily by the atmospheric conditions within the investigated area and by the surface temperature of the surrounding terrain. In snow-covered environments, the air temperature is usually above the snow surface temperature and the effects of the air between the topography and the receiving surface may be relevant.
Longwave irradiance from the surrounding terrain is an important component of the energy balance at the snow surface on inclined slopes and should be considered for areal investigations. A simple parameterization that accounts for the effects of the air is proposed for efficient calculation of longwave irradiance from snow-covered topography.
On the Potential Impact of Irrigated Areas in North America on Summer Rainfall Caused by Large-Scale Systems
Authors: Segal M. , Pan Z. , Turner R. W. , Takle E. S. 
Published: August 2010

AbstractThe potential impact of the increase in irrigated areas in North America during the past 100 years on summer rainfall associated with medium- to large-scale precipitation systems is evaluated conceptually and by several illustrative numerical model simulations. The model results for the simulated cases suggest a tendency toward some increase in the continental-average rainfall for the present irrigation conditions compared with those of past irrigation. The maximum increase obtained for several studied cases of 6-day duration each was 1.7%. Rainfall increases typically occur in the location of existing rainfall areas, and the main effect of irrigation is to redistribute rainfall in those preexisting precipitation regions.
Estimation of Surface and Top-of-Atmosphere Shortwave Irradiance in Biomass-Burning Regions during SCAR-B
Authors: Christopher Sundar A. , Li Xiang , Welch Ronald M. , Reid Jeffrey S. , Hobbs Peter V. , Eck Thomas F. , Holben Brent 
Published: August 2010

AbstractUsing in situ measurements of aerosol optical properties and ground-based measurements of aerosol optical thickness (τs) during the Smoke, Clouds and Radiation—Brazil (SCAR-B) experiment, a four-stream broadband radiative transfer model is used to estimate the downward shortwave irradiance (DSWI) and top-of-atmosphere (TOA) shortwave aerosol radiative forcing (SWARF) in cloud-free regions dominated by smoke from biomass burning in Brazil. The calculated DSWI values are compared with broadband pyranometer measurements made at the surface. The results show that, for two days when near-coincident measurements of single-scattering albedo ω0 and τs are available, the root-mean-square errors between the measured and calculated DSWI for daytime data are within 30 W m−2. For five days during SCAR-B, however, when assumptions about ω0 have to be made and also when τs was significantly higher, the differences can be as large as 100 W m−2. At TOA, the SWARF per unit optical thickness ranges from −20 to −60 W m−2 over four major ecosystems in South America. The results show that τs and ω0 are the two most important parameters that affect DSWI calculations. For SWARF values, surface albedos also play an important role. It is shown that ω0 must be known within 0.05 and τs at 0.55 μm must be known to within 0.1 to estimate DSWI to within 20 W m−2. The methodology described in this paper could serve as a potential strategy for determining DSWI values in the presence of aerosols. The wavelength dependence of τs and ω0 over the entire shortwave spectrum is needed to improve radiative transfer calculations. If global retrievals of DSWI and SWARF from satellite measurements are to be performed in the presence of biomass-burning aerosols on a routine basis, a concerted effort should be made to develop methodologies for estimating ω0 and τs from satellite and ground-based measurements.
Cloud Particle Phase Determination with the AVHRR
Authors: Key Jeffrey R. , Intrieri Janet M. 
Published: August 2010

Abstract
An accurate determination of cloud particle phase is required for the retrieval of other cloud properties from satellite and for radiative flux calculations in climate models. The physical principles underlying phase determination using the advanced very high resolution radiometer (AVHRR) satellite sensor are described for daytime and nighttime, cold cloud and warm cloud conditions. It is demonstrated that the spectral properties of cloud particles provide necessary, but not sufficient, information for phase determination, because the relationship between the cloud and surface temperatures is also important. Algorithms based on these principles are presented and tested. Validation with lidar and aircraft data from two Arctic field experiments shows the procedures to be accurate in identifying the phase of homogeneous water and ice clouds, though optically thin, mixed-phase, and multilayer clouds are problematic.
Temporal profile of vascular changes induced by systemic nitroglycerin in the meningeal and cortical districts
Authors: Greco Rosaria , Meazza Cristina , Mangione Antonina Stefania , Allena Marta , Bolla Monica , Amantea Diana , Mizoguchi Hirocazu , Sandrini Giorgio , Nappi Giuseppe , Tassorelli Cristina 
Published: August 2010

Background: Clinical studies indicated that nitric oxide (NO) donors cause regional changes in cerebral blood flow (CBF), similar to those reported in spontaneous migraine. Systemic nitroglycerin (NTG), a NO donor, is a well-accepted experimental model of migraine. In this study we have examined the effects of NTG on the meningeal and cortical blood flow in rats. Methods: Regional blood flow was monitored in male Sprague-Dawley rats using laser Doppler flowmetry before and after NTG/saline injection over 150 minutes. The effect of pre-treatment with Nω-nitro-L-arginine ester (L-NAME) or 7-nitroindazole (7-NI) on NTG-induced changes on blood flow was also investigated. Results: In the dura NTG caused a biphasic response represented by an initial decrease in blood flow followed by a significant increase. At variance, in the cortex NTG caused only an increase in blood flow. Pre-treatment with either L-NAME or 7-NI prevented NTG-induced increase in blood flow in both districts, while only L-NAME also prevented NTG-induced decrease in dural blood flow. Conclusion: The present findings provide additional information on the timing of effects of NTG on blood flow at both the meningeal and cortical levels. These effects seem to be related to vasoregulatory mechanisms and/or metabolic activity in response to the synthesis of endogenous NO.