Download or read book Field Measurement and Model Evaluation Program for Assessment of the Environmental Effects of Military Smokes Evaluation of Atmospheric Wind Field and Dispersion Models for Fog Oil Smoke Dispersion in Complex Terrain written by and published by . This book was released on 1992 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three models used to predict the wind field and pollutant dispersion in complex terrain are compared with smoke dispersion data acquired as part of the AMADEUS field experiments in 1987 near Red Bluff, California. The models evaluated were WADOCT, HOTMAC/RAPTAD, and RAMS. The data base for model testing encompassed 7 fog-oil smoke releases from ground level under stable meteorological conditions. Smoke concentrations were measured out to 4 km downwind. Time-dependent meteorological and source data were available from these tests to be used as model input. The results showed that the WADOCT model predicted quite well for the first 300 m downwind but then underpredicted the plume concentration by an order of magnitude at distances of 4 km downwind. The HOTMAC/RAPTAD model revealed a similar behavior. The inability of those two models to predict the trajectory of the plume and the observed limited vertical growth of the plume, in the downwind valley, are the likely causes of the underprediction. The RAMS model revealed very poor wind field and dispersion predictions based on the large grid spacing that was required (for this application) in order to make the computer run times manageable ... Smoke, Complex terrain, Dispersion modeling, Computer modeling, RA 3.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1993 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Field Measurement and Model Evaluation Program for Assessment of the Environmental Effects of Military Smokes Analysis Methods and Results of Hexachloroethane Smoke Dispersion Experiments Conducted as Part of Atterbury 87 Field Studies written by and published by . This book was released on 1989 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of five dispersion experiments conducted using hexachloroethane (HC) smoke pots are described. The experiments included: (a) measurement of time-dependent release rate (4 trials) and exit temperature (1 trial), (b) measurement of meteorological variables using a 10-m instrument tower and a 2-m mast upwind of the smoke source, (c) sampling of the particulate phase at four heights on 46 sampling masts organized into four transects located between 60 and 500 m from the source, (d) twelve samples of the vapor phase which were chemically analyzed for four specific organic compounds and (e) determination of the particle size distribution at a single location using a quartz-crystal-microbalance cascade impactor. Chemical analysis methods for the particulate and vapor phases are described. All particulate samples were analyzed for zinc and aluminum; 10 of the most heavily exposed filters were analyzed for 45 elements using a combination of inductively coupled argon- plasma, atomic-emission spectroscopy (40 elements) and ion chromatography (5 elements). Twenty-two additional samples were analyzed for 11 elements. A gas chromatography method used to analyze the vapor samples is also described. The results of the study include: (a) information on the approximate composition of the HC smoke particulate and vapor phases, (b) determination of the HC smoke particle size distribution and (c) concentration data with accompanying meteorological and source information which are suitable for testing and improving atmospheric dispersion models. Keywords: Screening smoke; Obscuring smoke; Gas chromatography.
Download or read book Government Reports Annual Index written by and published by . This book was released on 1993 with total page 1836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Survey and Evaluation of Field Data Suitable for Smoke Hazard Model Evaluation written by Anthony J. Policastro and published by . This book was released on 1985 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents a summary and critical evaluation of the existing data on the dispersion of military smokes. Emphasis is placed on fog oil smokes in terms of the measurement of concentration, dosage, particle size distribution, and mass deposition rate. The suitability of the available data for evaluating atmospheric dispersion models for health and environmental impacts purposes is marginal. Several questions remain as to the adequacy of the sampling techniques used and the validity of some of the supporting meteorological data. The best of the existing dataw onf og oil smoke dispersion were acquired during the Smoke Week IIi and IV experiments. Keywords: Aerosol photometers; Plume models; Mathematical models. (author).
Download or read book Assessment and Computerized Modeling of the Environmental Deposition of Military Smokes Characterization of the Atmospheric Boundary Layer in Complex Terrain and Results from the Amadeus Smoke Dispersion Experiments written by D. F. Brown and published by . This book was released on 1991 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes our analysis of the AMADEUS meteorological data Preliminary analysis (also given in Brown et al. 1990) of these data for each of the smoke-release periods include: (1) computation of averages of the surface-station and micrometeorological measurements (wind speed, wind direction, temperature), (2) stability characterization by analysis of bulk Richardson numbers and wind direction standard deviations, (3) examination of vertical heat and momentum fluxes from sonic-anemometer data, (4) analysis of spectra computed using 1-Hz micrometeorological data and (5) determination of boundary-layer height from the instrumented balloon soundings. Additional results given in this report include: (1) an analysis of vertical wind profiles, (2) comparisons of Meadowbrook data to similarity-based empirical relations and (3) a comprehensive analysis of the noctumal down-slope flows. The results show that the meteorological data are consistent, both internally and with other studies of the atmospheric boundary layer. The daytime convective conditions reveal a high degree of coherency, whereas the nighttime stable conditions are more spatially heterogeneous and less coherent. Analysis of surface-station data has shown that the characteristics of the nocturnal downslope flows in the Meadowbrook valleys are influenced by a combination of local cooling, local surface conditions and mesoscale drainage flows external to the Meadowbrook system. These data appear to offer significant potential for improving the state of dispersion modeling in this important area. RA 3, smoke, screening smoke, obscuring smoke, hexachloroethane, gas chromatography.
Download or read book Assessment and Computerized Modeling of the Environmental Deposition of Military Smokes Analysis of Meteorological Data from the AMADEUS Smoke Dispersion Experiments written by D. F. Brown and published by . This book was released on 1990 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the meteorological data collected as part of the AMADEUS dispersion experiments. In addition, a preliminary analysis of these data was carried out. Averages of the surface-station and micrometeorological measurements were computed for each of 12 smoke release periods. Also, the stability of the atmosphere during these tests was characterized by analyzing (1) the standard deviation of the horizontal wind direction; (2) the bulk Richardson number; (3) the vertical profiles of wind and atmospheric temperature; and (4) direct measurements of the vertical heat and momentum fluxes. For four of the five daytime releases, the height of the boundary layer was determined from instrumented balloon soundings. Results show that the meteorological data are complete and consistent, both internally and with other studies of the atmospheric boundary level. The daytime convective conditions reveal a high degree of coherency, whereas the nighttime stable conditions are more spatially heterogeneous and less coherent. The stable boundary layer is generally less well understood than is the convective boundary layer, especially in a complex terrain setting. The data appear to offer significant potential for improving the state of dispersion modeling in this important area.
Download or read book EPA Complex Terrain Model Development written by and published by . This book was released on 1988 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dispersion Modeling Protocol for Ambient Air Quality Impact Assessment written by United States. Bureau of Land Management. Miles City Field Office and published by . This book was released on 2006 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Use of Field Experimental Studies to Evaluate Emergency Response Models written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The three-dimensional diagnostic wind field model (MATHEW) and the particle-in-cell atmospheric transport and diffusion model (ADPIC) are used by the Atmospheric Release Advisory Capability to estimate the environmental consequences of accidental releases of radioactivity into the atmosphere. These models have undergone extensive evaluations against field experiments conducted in a variety of environmental settings ranging from relatively flat to very complex terrain areas. Simulations of tracer experiments conducted in a complex mountain valley setting revealed that 35 to 50% of the comparisons between calculated and measured tracer concentrations were within a factor of 5. This may be compared with a factor of 2 for 50% of the comparisons for relatively flat terrain. This degradation of results in complex terrain is due to a variety of factors such as the limited representativeness of measurements in complex terrain, the limited spatial resolution afforded by the models, and the turbulence parameterization based on sigma/sub theta/ measurements to evaluate the eddy diffusivities. Measurements of sigma/sub theta/ in complex terrain exceed those measured over flat terrain by a factor of 2 to 3 leading to eddy diffusivities that are unrealistically high. The results of model evaluations are very sensitive to the quality and the representativeness of the meteorological data. This is particularly true for measurements near the source. The capability of the models to simulate the dispersion of an instantaneously produced cloud of particulates was illustrated to be generally within a factor of 2 over flat terrain. 19 refs., 16 figs.
Download or read book Terrain Responsive Atmospheric Code TRAC for Plume Growth and Dispersion in Complex Terrain written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Use of atmospheric dispersion models to assess pollutant impacts in complex terrain is increasing. However, the temporally and spatially varying wind and turbulence fields in mountainous areas often invalidate the assumptions of straight-line flow and horizontal homogeneity inherent in standard plume models. A dispersion model was recently developed at the Rocky Flats Plant to realistically simulate dispersion processes in complex terrain. The new model treats pollutant releases as a series of overlapping ellipsoidal puffs. The ends of each puff axis are defined by ''tracer'' particles, which are independently advected through the modeled windfield. The puff axes are not, in general, orthogonal. Thus, a puff can develop an arbitrary shape in response to differential diffusion rates, horizontal convergence and divergence, vertical shear, surface reflection, and gravitational settling. The model includes modules for puff transport, diffusion, wet and dry deposition, resuspension, surface roughness effects, ingrowth, decay, and external and internal dosimetry. This report focuses on the simulation of puff growth and shape.
Download or read book Evaluation of Atmospheric and Dispersion Models in Complex Terrain by Using Tracer Measurements written by Vlad Isakoc and published by . This book was released on 1998 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Field Measurements in Support of Dispersion Modeling in Complex Terrain written by Wynn Eberhard and published by . This book was released on 1981 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atmospheric and Dispersion Modeling in Areas of Highly Complex Terrain Employing a Four dimensional Data Assimilation Technique written by and published by . This book was released on 1994 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 predicting the qualitative flow during this evening, additional experiments need to be performed to improve the prognostic forecasts made by RAMS and refine the FDDA procedure so that the overall errors are reduced even further. Despite the fact that a great deal of computational time is necessary in executing RAMS and LPDM in the configuration employed in this study, recent advances in workstations is making applications such as this more practical. As the speed of these machines increase in the next few years, it will become feasible to employ prognostic, three-dimensional mesoscale/transport models to routinely predict atmospheric dispersion of pollutants, even to highly complex terrain. For example, the version of RAMS in this study could be run in a ''nowcasting'' model that would continually assimilate local and regional observations as soon as they become available. The atmospheric physics in the model would be used to determine the wind field where no observations are available. The three-dimensional flow fields could be used as dynamic initial conditions for a model forecast. The output from this type of modeling system will have to be compared to existing diagnostic, mass-consistent models to determine whether the wind field and dispersion forecasts are significantly improved.
Download or read book Evaluate and Characterize Mechanisms Controlling Transport Fate and Effects of Army Smokes in an Aerosol Wind Tunnel Transport Transformations Fate and Terrestrial Ecological Effects of Fog Oil Obscurant Smokes written by and published by . This book was released on 1989 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The terrestrial transport, chemical fate, and ecological effects of fog oil (FO) smoke obscurants were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: 1) natural vegetation characteristic of U.S. Army training sites in the United States; 2) physical and chemical properties of soils representative of these training sites; and 3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on an exposure scenario, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and three soil types. Fog oil enhanced the microbial activities in most of the metabolic parameters evaluated. A cumulative dose of fog oil exposure stimulated soil respiration slightly and increased nitro-bacter population in Palouse soil, and greatly increased soil enzyme activity in both Palouse and Burbank soil. Earthworm bioassays indicated no adverse effect of fog oil with exposures up to 800 micrograms/sq. cm soil. In vitro studies, where fog oil was uniformly amended to soil, showed earth- worm survival to be 100% until an exposure of approx. 3600 micrograms/sq. cm (a soil concentration of 285 micrograms FO/g) was reached.
