利用CAM5.1模拟中国东部大规模城市化对东亚地区夏季大气环流及降水分布的影响

Simulations of the impact of the large-scale urbanization in eastern China on the atmospheric circulation and rainfall distribution around eastern Asia using CAM5.1

利用CAM5.1大气环流模式研究中国东部大规模城市化对东亚夏季大气环流及降水分布的影响。通过在模式中修改中国东部地区(22～42°N,110～125°E)城市比重的方法,探讨东亚地区夏季大气环流与降水等气象要素在一般城市化及极端城市化两种情景下的响应。结果表明:(1)CAM5.1模式能够很好地模拟出东亚地区夏季大气环流形势及降水分布。(2)城市比重增大后,晴空时地面吸收的净辐射增多,近地层气温升高,低层增温中心上空的大气由于受热产生上升运动,35°N以南的气流向增温区辐合,东亚夏季风出现增强的趋势,大量暖湿水汽往北输送,导致降水在中国北方地区增多而南方减少。(3)城市化的发展程度越高,它所产生的气候效应对各气象要素的影响就表现得越明显。

By setting different percentages of urban area,this article studies the impact of the large-scale urbanization in eastern China on the atmospheric circulation and rainfall distribution around eastern Asia using CAM5.1（Community Atmosphere Model Version 5.1）.The results indicate that：（1）Simulation results of both atmospheric circulation and physical quantities such as air temperature and precipitation by using CAM5.1 are reasonable;（2）As the percentage of urban area rises,the corresponding net radiation by clear sky on the ground goes up,the higher air temperature in ground layer leads to ascending motion around the warming center as well as southerly winds in the south of 35 °N.Thus the east Asian summer monsoon becomes stronger and the rainfall distribution becomes abnormal with more rain in the north but with less rain in the south of China.