Numerical Simulations For The Impact Of Large-scale Urbanization In Eastern China On Summer And Winter Atmospheric Circulation And Rainfall Distribution Around Eastern Asia

Using the latest Community Atmosphere Model Version5.1from NCAR, this article focuses on the impacts of large-scale urbanization around eastern China on the summer and winter circulation and rainfall distribution around eastern Asia. Two aspects of urbanization are discussed in this paper-the change of underlying ground surface and the discharging volume of black carbon aerosol.The main results are as follows:(1) The simulation results of global and eastern Asian atmosphere circulation in summer and winter using CAM5.1are very similar to the observation results.(2) When the percentage of urban underlying surface rises, the nearby low level air temperature of summer goes up, and the abnormal sea level pressure(slp) around eastern Asia represents positive and negative pattern from the north to the south. An abnormal cyclone appears around the eastern coast of China, which centers around Jianghuai region. The rainfall distribution appears to be positive and negative pattern from the eastern to western China. The characteristics of simulation results are very similar to the observational facts.(3) When the percentage of urban underlying surface rises, the nearby winter temperature rises significantly even up to200hPa, meanwhile, the slp drops and an abnormal anticyclone appears to the east of Taiwan, the southerly wind between the two abnormal systems lead to more rainfall in most of China.(4) When the volume of black carbon aerosol around eastern China doubles, the air temperature rises from the low level to the middle level in summer, together with a slight reduction of surface air temperature near Shandong. An abnormal anticyclone appears around South China Sea, the southerly wind to the north of the anticyclone affects the eastern part of China, and the abnormal rainfall distribution represents negative, positive and negative pattern from the south to the north of eastern China.(5) When the volume of black carbon aerosol around eastern China doubles, a reduction of surface air temperature appears nearby. There forms an abnormal cyclone, which centers around110°E, thus the eastern China is controlled by southerly wind and most region of China gets more precipitation in winter.