Simulation Of The Direct And First Indirect Effect Of Anthropogenic Sulfate And Its Effects On Regional Climate Of China

The spatial and temporal distribution of sulfate column abundances and their direct as well as first indirect effect over East Asia from December2008to November2009have been investigated using the regional Climate Model version3(RegCM3) through introduction of a new aerosol emissions with high resolution, and the parameterization of aerosol activation. The main conclusions drawn from this study are as follows:1. The spatial distribution of sulfate emission and columns strongly depend on human activities, with the high value centers over Sichuan basin, middle and east China accompanied by heavy industry and large population coursing heavy pollution. The results show marked seasonal variation of the sulfate distribution due to general circulation, with sulfates accumulating over south of Yangzi River in winter and transporting northeastward by advection during the summer resulted from the southwester lies associated with the monsoon circulations. Aerosols from India Peninsula have significant effect over middle and east china with the influence of southwest airflow.2. The distribution of direct radiative forcing have good correlation with sulfate column abundances, which lead to negative radiative forcing on top of atmosphere with seasonal variations. The maximum value of radiative forcing maximums occurs in Summer (-2.99W/m2), and the annual average value is-2.41W/m2. The sulfate aerosol direct effects lead to decrease of surface temperature with significant influence in Sumer (0.26℃) compared with annual average value of0.09℃, and suppress of precipitation with annual average value of0.048mm/d, which changes with different areas and seasons.3. The temporal and spatial distribution of the first indirect forcing of sulfate aerosols are similar to their direct effects, which have good correlation with variation of effective radius of cloud droplets and distribution of sulfate column abundances, with maximum value in summer (-3.06W/m2) and annual mean value of-2.2W/m2. The surface temperatures reduce considering the first direct effects, with apparent cool down in Winter and Summer (0.21and0.20℃) in contrast to annual mean value of0.12℃. The analysis of typical areas shows that surface temperatures are dominated by cloud cover vertical variations. The precipitation diminishes as a result of first indirect effect with annual average values of O.Olmm/d, but differ with varied areas and seasons..