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ADAPTATION OF THE ADVANCED STATISTICAL TRAJECTORY REGIONAL AIR POLLUTION (ASTRAP) MODEL TO THE EPA VAX COMPUTER - MODIFICATIONS AND TESTING
Citation:
Clark, T. AND D. Coventry. ADAPTATION OF THE ADVANCED STATISTICAL TRAJECTORY REGIONAL AIR POLLUTION (ASTRAP) MODEL TO THE EPA VAX COMPUTER - MODIFICATIONS AND TESTING. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/3-90/083 (NTIS PB91127720), 1990.
Description:
The Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model simulates long-term transport and deposition of oxides of and nitrogen. t is a potential screening tool for assessing long-term effects on regional visibility from sulfur emission sources. owever, a rigorous evaluation is required before this model can be recommended for this particular application. s a first step, we modified the original 1985 IBM-3033 version of this model to create the ASTRAP-EPA version for applications on the EPA VAX computer using existing EPA preprocessed meteorological and emissions data files. dditional modifications improved the model design by eliminating several model assumptions and replacing some modeling approaches. he cumulative effect of the model modifications was assessed by comparing the quarterly 1980 calculations of sulfur wet deposition of both versions with screened measurements. he seasonal correlation coefficients and standard errors of each model version are insignificantly different at the 0.05 level, demonstrating that the two model versions indeed produce similar results. n general, the improvements in model design only slightly enhance model performance. ensitivity of ASTRAP-EPA calculations of sulfur wet deposition was also assessed for several model assumptions and values of model parameters. STRAP-EPA model predictions are most sensitive to three parameters - the model time step, the truncation of trajectories near the border of wind-data-void regions, and the temporal aggregation of ensemble trajectory statistics. he quarterly predictions of wet deposition, across southwestern Pennsylvania and northern West Virginia, decrease by as much as 30 percent when either the model time step from 3 hours to 6 hours, or trajectories are not truncated, or trajectory statistics are not temporally aggregated.
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ADAPTATION OF THE ADVANCED STATISTICAL TRAJECTORY REGIONAL AIR POLLUTION (ASTRAP) MODEL TO THE EPA VAX COMPUTER - MODIFICATIONS AND TESTING