Sensitivity Analysis of a Climatological Air Trajectory Model
The modeling of regional-scale transport and deposition of atmospheric pollutants is complicated by the considerable uncertainties involved in atmospheric process parameterizations. Beyond the uncertainties involved in parameterizing dispersion over relatively short distances (say less than 50 km) is the need to estimate dispersion over long time scales, usually including multi-diurnal cycles. Moreover, other atmospheric processes, usually ignored, must be considered. Dry deposition plays an important role as a removal process over long time scales and must be parameterized in a physically realistic manner. The removal of pollutants by wet deposition is an extremely complex process parameterized at best to be a simple non-linear function. Chemical conversion of primary pollutants to secondary is also poorly understood but has been parameterized for some pollutants, notably sulfur dioxide to sulfate, as a first-order chemical conversion. The purpose of this paper is to examine the sensitivity of individual trajectory model runs to variations in model parameterizations. This information is intended to help define the confidence in which we can hope to characterize the effects of anthropogenic emissions on receptor locations far downwind of the source.
KeywordsSulfur Dioxide Deposition Velocity Vertical Wind Shear Trajectory Model Chemical Conversion
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- Engelmann, R.J., Scavenging prediction using ratios of concentrations in air and precipitation, AEC Symp. Ser. Precipitation Scavenging (1970), 475.Google Scholar
- Heffter, J.L., 1980: “Air Resources Laboratories Atmospheric Transport and Dispersion Model (ARL-ATAD),” NOAA Tech. Memo. ERL-ARL-81, Silver Springs, MD.Google Scholar