A Model for Pollutant Concentration Prediction in Complex Terrain

Abstract

In modeling the distributions of atmospheric pollutants, the study of the effects of the topography on the pollutants is of vital importance. As the terrain is flat, the Gaussian dispersion model is the basic method used to calculate pollutant concentrations. However, the Gaussian dispersion models are found to overpredict the concentration over mountainous terrain (Start, et. al., 1977). In order to better understand dispersion over complex terrain, the sophisticated dynamic model based on second-order closure schemes (Yamada, 1979) has been constructed. Due to the complexity of dynamic model, an alternative approach with the use of statistical method for analyzing the dynamic relationship between the geostrophic wind, vertical heat flux and surface wind over complex terrain was proposed (Kau et. al., 1981). The results were encouraging. It was found that the correlations between the calculated and observed surface wind speed were high for all time periods of the day and night. The surface wind speed was dependent primarily on the slope wind, cross isobaric angle, surface thermal stability and geostrophic wind. The wind direction was dependent primarily on the geostrophic wind direction, aspect angle of the topography, upcanyon direction and cross isobaric angle. In this paper, extending the works of Kau et. al., (1982) intend to predict the pollutant concentration over complex terrain.