Seasonal and Spatial Variation of Radiative Effects of Anthropogenic Sulfate Aerosol

On the basis of the emission data of the industrial sulphur dioxide (SO2) and observed climate fields over East Asia, the distribution of anthropogenic sulfate aerosol (SO) with seasonal variation in the troposphere is simulated and analyzed by a regional sulfur transport model, and the direct radiative effects of SO under different weather conditions are also calculated using the discrete ordinate method. The results show that the concentration of SO has significant seasonal and spatial variations resulting from the effects of SO2 emission source and precipita-tion and wind fields. Both the concentration of SO2 and its radiative forcing have the largest values in October and the lowest in July. SO causes the decrease of the radiation flux absorbed by earth-atmosphere and the cooling of air temperature by scattering more solar radiation back into space. Besides, the radiative and climatic effects of SO are related to the types and height and optical thickness, etc., of the clouds.