华东区域夏季行星边界层大气稳定度的气候特征及其与气溶胶的联系

Mean climatology and interannual variations of the atmospheric stability of planetary boundary layer in the eastern China during boreal summer

利用1979—2008年夏季(6—8月)逐日NCEP/NACR再分析资料、MODIS卫星的气溶胶资料等,研究了华东区域夏季行星边界层大气稳定度的气候特征与年际变化,分析了大气稳定度和相应的加热场与气溶胶光学厚度(aerosol optical depth,AOD)的联系。结果表明:华东区域夏季行星边界层大气稳定度在空间上分布不均匀,时间上具有明显的年际变化。边界层中的非绝热加热率、大气稳定度及气溶胶光学厚度三者之间可能存在密切联系。利用经验正交函数分析了华东区域总体理查森数Ri b的距平场,得到了边界层稳定度分布的3个主要模态,这3个模态所代表的边界层大气稳定度异常与夏季风环流异常密切相关,特别是P-J型遥相关波列和西太平洋副热带高压在中国东部大气边界层稳定度变化中可能起着非常重要的作用。

The multiyear mean climatological and interannual variations of the summertime atmospheric stability associated with the heating and aerosol optical depth （AOD） have been investigated using the NCEP/NCAR reanalysis data and the aerosol data of MODIS satellite over the eastern China during 1979--2008. Results show that the spatial distribution of atmospheric stability in the planetary boundary layer is inhomogeneous, and it exhibits interannual variations. The mean climatology of atmospheric sta- bility is found to be in association with the mean climatological distributions of the diabatic heating and aerosol optical depth（AOD）. Three principal modes of the anomalous overall Richardson number（ Rib ） in East China are found by performing the empirical orthogonal function analysis. It is indicated that dif- ferent leading modes of Rib are closely related to the summer monsoon circulation anomalies, especially the P-J type teleconnection pattern and the western Pacific subtropical high, which may play a very im- portant role in the stability change of the boundary atmosphere in East China.