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Atmospheric and dispersion modeling in areas of highly complex terrain employing a four-dimensional data assimilation technique

Description: The results of this study indicate that the current data assimilation technique can have a positive impact on the mesoscale flow fields; however, care must be taken in its application to grids of relatively fine horizontal resolution. Continuous FDDA is a useful tool in producing high-resolution mesoscale analysis fields that can be used to (1) create a better initial conditions for mesoscale atmospheric models and (2) drive transport models for dispersion studies. While RAMS is capable of pred… more
Date: December 31, 1994
Creator: Fast, J. D. & O`Steen, B. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Thermohaline circulations and global climate change. Final report

Description: This research is ultimately concerned with investigating the hypothesis that changes in surface thermal and hydrological forcing of the North Atlantic, changes that might be expected to accompany CO2-induced global warming, could result in ocean-atmosphere interactions` exerting a positive feedback on the climate system. This report concerns research conducted with funding from the Carbon Dioxide Research Program (now the Global Climate Change Program) of the US Department of Energy via grant n… more
Date: September 1, 1994
Creator: Hanson, H. P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Proceedings of the third Atmospheric Radiation Measurement (ARM) science team meeting

Description: This document contains the summaries of papers presented at the 1993 Atmospheric Radiation Measurement (ARM) Science Team meeting held in Morman, Oklahoma. To put these papers in context, it is useful to consider the history and status of the ARM Program at the time of the meeting. Individual papers have been cataloged separately.
Date: March 1, 1994
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Short-tower {sigma}{sub {theta}} measurements in the Colorado Plateaus region

Description: The standard deviation of the wind direction, {sigma}{sub {theta}}, is related to horizontal turbulent diffusion in the atmosphere and has been widely used in pollutant dispersion calculations. The elevation and exposure of sites in complex terrain is associated with the statistics of the distribution of hourly wind direction standard deviation. At ridge-top sites during the cool season, hourly {sigma}{sub {theta}} distributions have small standard deviations and positive kurtosis. Open-exposur… more
Date: January 1, 1994
Creator: Hauser, R. K.; Whiteman, C. D. & Allwine, K. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Variational elliptic solver for atmospheric applications

Description: We discuss a conjugate gradient type method -- the conjugate residual -- suitable for solving linear elliptic equations that result from discretization of complex atmospheric dynamical problems. Rotation and irregular boundaries typically lead to nonself-adjoint elliptic operators whose matrix representation on the grid is definite but not symmetric. On the other hand, most established methods for solving large sparse matrix equations depend on the symmetry and definiteness of the matrix. Furth… more
Date: March 1, 1994
Creator: Smolarkiewicz, P. K. & Margolin, L. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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On the development of boundary layer secondary circulations resulting from horizontally varying surface heat flux

Description: During the last decade there has been a surge in efforts to understand the processes at work in the inhomogeneous atmospheric boundary layer. Much of the interest in the problem has been driven by increasingly urgent needs to develop accurate assessments of man`s Contribution to climate change. It has been argued that subgrid-scale secondary circulations in the boundary layer can cause significant errors in parameterized turbulent surface fluxes. Such circulations -- variously termed ``inland b… more
Date: March 1, 1994
Creator: Shaw, W. J. & Doran, J. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulation of stellar speckle imaging

Description: Standard FFT-based phase screen generation methods do not accurately model low frequency turbulence characteristics. This paper introduces a new phase screen generation technique which uses low frequency subharmonic methods. The structure functions for this new method match very closely the structure functions of Kolmogorov turbulence theory.
Date: April 1, 1994
Creator: Johansson, E. M. & Gavel, D. T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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An experimental and numerical study of the modifications of mixed-layer structure by inhomogeneous surface fluxes and secondary circulations

Description: The problem of scale interactions in the planetary boundary layer (PBL), i.e., how forcing mechanisms of differing spatial and temporal scales affect the properties of the PBL, has been a subject of considerable interest for some time. One aspect of this problem that has received increasing attention in recent years is the representation, in mesoscale and general circulation models. of the effects of subgrid-scale inhomogeneities in surface properties. Differences in sensible and latent heat fl… more
Date: July 1, 1994
Creator: Zhong, S. & Doran, J. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A hyperspectral image data exploration workbench for environmental science applications

Description: The Hyperspectral Image Data Exploration Workbench (HIDEW) software system has been developed by Argonne National Laboratory to enable analysts at Unix workstations to conveniently access and manipulate high-resolution imagery data for analysis, mapping purposes, and input to environmental modeling applications. HIDEW is fully object-oriented, including the underlying database. This system was developed as an aid to site characterization work and atmospheric research projects.
Date: August 1, 1994
Creator: Woyna, M. A.; Christiansen, J. H.; Zawada, D. G. & Simunich, K. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Recent changes of weather patterns in North America. Progress report for period ending April 1, 1994

Description: This report contains information dealing with climatic change in North America. Results gathered from present and previous DOE contracts are discussed. These include: usage of the Historical Climatology Network, characteristics of recent climate change, impacts of increasing anthropogenic greenhouse gases, seasonal trends, geographic and seasonal distribution of temperature anomalies, paleoclimates, weather pattern differences between eastern and western regions, daily temperature variations, g… more
Date: August 1, 1994
Creator: Kukla, G. J. & Karl, T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Load-balancing algorithms for climate models

Description: Implementations of climate models on scalable parallel computer systems can suffer from load imbalances due to temporal and spatial variations in the amount of computation required for physical parameterizations such as solar radiation and convective adjustment. We have developed specialized techniques for correcting such imbalances. These techniques are incorporated in a general-purpose, programmable load-balancing library that allows the mapping of computation to processors to be specified as… more
Date: June 1, 1994
Creator: Foster, I. T. & Toonen, B. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The role of large-scale, extratropical dynamics in climate change

Description: The climate modeling community has focused recently on improving our understanding of certain processes, such as cloud feedbacks and ocean circulation, that are deemed critical to climate-change prediction. Although attention to such processes is warranted, emphasis on these areas has diminished a general appreciation of the role played by the large-scale dynamics of the extratropical atmosphere. Lack of interest in extratropical dynamics may reflect the assumption that these dynamical processe… more
Date: February 1, 1994
Creator: Shepherd, T. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Real-time modeling of complex atmospheric releases in urban areas

Description: If a nuclear installation in or near an urban area has a venting, fire, or explosion, airborne radioactivity becomes the major concern. Dispersion models are the immediate tool for estimating the dose and contamination. Responses in urban areas depend on knowledge of the amount of the release, representative meteorological data, and the ability of the dispersion model to simulate the complex flows as modified by terrain or local wind conditions. A centralized dispersion modeling system can prod… more
Date: August 1, 1994
Creator: Baskett, R. L.; Ellis, J. S. & Sullivan, T. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Modeling atmospheric concentrations and deposition of Hg

Description: The deleterious effects on ecosystems of mercury pollution are well established and fish advisories are in effect for many lakes in North America. Because methylation and other transformation processes in ecosystems can alter the original speciation of deposited Hg, a decrease in atmospheric loading of Hg in all forms is highly desirable. The contribution to Hg deposition by emissions from current anthropogenic activities relative to the deposition contribution by emissions from natural process… more
Date: June 1, 1994
Creator: Shannon, J. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Hierarchical framework for coupling a biogeochemical trace gas model to a general circulation model

Description: A scheme is described for the computation of terrestrial biogeochemical trace gas fluxes in the context of a general circulation model. This hierarchical system flux scheme (HSFS) incorporates five major components: (1) a general circulation model (GCM), which provides a medium-resolution (i.e., 1{degrees} by 1{degrees}) simulation of the atmospheric circulation; (2) a procedure for identifying regions of defined homogeneity of surface type within GCM grid cells; (3) a set of surface process mo… more
Date: April 1, 1994
Creator: Miller, N. L. & Foster, I. T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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ARM: A climate process observatory

Description: In May 1992 the Department of Energy`s Atmospheric Radiation Measurement (ARM) Program began deploying instrumentation and conducting measurements at its first field site near Lamont in North Central Oklahoma. ARM is a major program of atomospheric measurement and modeling intended to improve understanding of the processes and properties that affect atmospheric radiation. Particular emphasis is being placed on the role of clouds in radiative transport and on improving the representation of clou… more
Date: January 1, 1994
Creator: Stokes, G. M. & Pennell, W. T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A parameterization of cloud droplet nucleation

Description: Droplet nucleation is a fundamental cloud process. The number of aerosols activated to form cloud droplets influences not only the number of aerosols scavenged by clouds but also the size of the cloud droplets. Cloud droplet size influences the cloud albedo and the conversion of cloud water to precipitation. Global aerosol models are presently being developed with the intention of coupling with global atmospheric circulation models to evaluate the influence of aerosols and aerosol-cloud interac… more
Date: January 1, 1994
Creator: Ghan, S. J.; Chuang, C. C. & Penner, J. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Environmental Sciences Division annual progress report for period ending September 30, 1994

Description: This progress report summarizes the research and development activities conducted in the Environmental Sciences Division (ESD) of Oak Ridge National Laboratory during fiscal year (FY) 1994, which extended from October 1, 1993, through September 30, 1994. The report is structured to provide descriptions of current activities and accomplishments in each of the division`s major organizational units. Following the sections describing the organizational units are sections highlighting ESD Scientific… more
Date: December 31, 1994
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The northern wintertime divergence extrema at 200 hPa and surface cyclones as simulated in the AMIP integration of the ECMWF general circulation model

Description: Divergence and convergence centers at 200 hPa and mean sea level pressure (MSLP) cyclones were located every 6 hr for a 10-yr general circulation model (GCM) simulation with the ECMWF (Cycle 36) for the boreal winters from 1980 to 1988. The simulation used the observed monthly mean sea surface temperature (SST) for the decade. Analysis of the frequency, location, and strength of these centers and cyclones gives insight into the dynamical response of the model to the varying SST. The results ind… more
Date: November 1, 1994
Creator: Boyle, J. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High resolution properties of the marine atmospheric boundary layer

Description: Los Alamos National Laboratory (LANL) participated in the Central Equatorial Pacific Experiment (CEPEX) by fielding a water-vapor Raman lidar on board the Research Vessel Vickers. The lidar measured water vapor concentration from the surface to lower tropospheric altitudes in order to support the CEPEX goal of evaluating a hypothesis regarding feedback mechanisms for global circulation models. This report describes some of the features observed within the marine Atmospheric Boundary Layer (ABL)… more
Date: February 1, 1994
Creator: Cooper, D.; Cottingame, W.; Eichinger, W.; Forman, P.; Lebeda, C.; Poling, D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Meteorological Monitoring program at a former nuclear weapons plant

Description: The purpose of the Meteorological Monitoring program at Rocky Flats Plant (RFP) is to provide meteorological information for use in assessing the transport, and diffusion, and deposition of effluent actually or potentially released into the atmosphere by plant operations. Achievement of this objective aids in protecting health and safety of the public, employees, and environment, and directly supports Emergency Response programs at RFP. Meteorological information supports the design of environm… more
Date: February 1, 1994
Creator: Maxwell, D. R. & Bowen, B. M.
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Partner: UNT Libraries Government Documents Department
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Stability effects on the profiles of vertical velocity and its variance in katabatic flow

Description: The atmospheric katabatic flow in the foothills of the Front Range of the Rocky Mountains has been monitored by a network of towers and sodars for several years as part of the Atmospheric Studies in Complex Terrain (ASCOT) program. The dependence of the vertical component of motion, its variance, and the mean component of the wind perpendicular to the surface at the mouth of Coal Creek Canyon on surface cooling and channeling by winds above the canyon has been explored by using almost three yea… more
Date: October 1, 1994
Creator: Coulter, R. L. & Martin, T. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The effect of regional-scale soil-moisture deficits on mesoscale atmospheric dynamics that influence fire severity

Description: This study employs a three-dimensional, nonhydrostatic mesoscale model to evaluate the effects of horizontally heterogeneous soil moisture and vegetation type on the atmosphere during two periods in which wildland fires occurred. Numerical sensitivity simulations demonstrate that evapotranspiration significantly affects the boundary-layer structure embedded in the synoptic-scale circulations. In regions with sufficiently moist soils, evapotranspiration increases the humidity and modifies the di… more
Date: September 30, 1994
Creator: Fast, J. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Semidiurnal solar tides in the mountain atmosphere

Description: Harmonic analysis of Doppler radar wind profiler data west of the Rocky Mountains has identified a coherent semidiurnal wind system above the wintertime boundary layer at multiple sites in the region. The unusual characteristics of this mountain wind system (its semidiurnal frequency, amplitude, phase, and direction of rotation) suggest that is is a semidiurnal solar tide. Such tides have not been previously documented in the mountain atmosphere or in the troposphere generally but, because semi… more
Date: September 1, 1994
Creator: Whiteman, C. D. & Bian, X.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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