NUMERICAL SIMULATION OF THERMAL STRUCTURE OF URBAN POLLUTED ATMOSPHERE.

Two-dimensional numerical simulation is carried out on the unsteady heat transfer in the urban polluted boundary layer containing aerosols. The effects of aerosols upon the thermal structure over the region including urban area are studied synthetically in full consideration of radiative heat transfer. The results indicate the strong interaction among the distribution of air temperature, wind velocity and aerosol concentration in connection with the scattering and absorbing characteristics of aerosols. When the scattering of solar radiation by aerosols is predominant, the air temperature in urban area drops largely, and the convergent flow to the urban area becomes weak, so that the aerosol concentration in urban area becomes high. When the absorption of solar radiation is predominant, the convergent flow to the urban area is not weakened. Air temperature drops near the earth surface, but the change in the upper air temperature is small.