干侵入对2005年8月16日华北暴雨的作用

Impact of Dry Intrusion on Heavy Rain Process of 16 August 2005 in North China

利用NCEP/NCAR再分析资料、自动站观测资料以及中尺度数值模式MM5V3.7输出结果,对2005年8月16—17日发生在华北的一次暴雨过程的成因做了诊断分析。结果表明:在暴雨产生过程中有干冷空气的入侵,对这次暴雨过程的发生、发展有重要作用,高层干冷空气的侵入有利于低层中尺度气旋的发展,使暴雨过程得以维持和加强。

A heavy rainstorm happened in North China during the period from 0000 UTC 16th to 0000 UTC 17th August 2005 ,and the strongest rainstorm occurred in Tianjin. By use of surface observation data and NCEP/NCAR reanalysis data and results of the mesoscale numerical model MM5V3.7, the circulation features and heavy rain in North China during 16th to 17th August 2005 were diagnosed and analyzed. The results show that the dry cold air intrusion had important impact on the rainstorm. The dry air in the upper troposphere intruded into the lower level was in favor of the development and enhancement of the meso-scale cyclone.