2009年7月22日阜阳市沿淮地区暴雨天气过程分析

该文利用NCEP/NCAR再分析资料和安徽省气象自动观测网资料对北京时间2009年7月22日发生在阜阳市沿淮地区强降水过程的环流形势、地面流场、散度及水汽通量散度进行了空间上与时间上的综合分析。结果表明：副高势力较强，其在南北位置上较为稳定少移，有利于西南暖湿气流吹向淮河流域，与之前的西北干冷空气汇合，促使降水开始增大；低空辐合引起垂直运动，随之出现强烈的辐合辐散，引发垂直对流产生，是此次暴雨过程产生的启动机制；在整个降水过程中，散度与强降水有很好的对应关系，降水最大时刻，对应低层强辐合，高层强辐散，散度作为强迫项激发了地面中尺度系统的发展与次级环流的形成，同时水汽的大量辐合为强降水提供了丰富的水汽条件，使得此次暴雨得以发展与维持。

Comprehensive Analysis of Heavy Rain Process in Fuyang on July 22,2009

By using NCEP/NCAR reanalyzed data and Anhui Province automatic meteorological observation network data,a heavy rain process is comprehensively analyzed in Fuyang on July 22,2009.The results are as follows,Huai?he river basin was between 584dgpm line and 588dgpm line,subtropical high pressure was stable,which provided fa?vorable conditions for convergence of warm and wet air from south and dry air from north on 500hPa,water vapor channel provided rich water for the rain,all the factors provided good background for the rainstorms in Huaihe;Low-level convergence ascending became the main trigger mechanism of heavy rain;the divergence was taken as an only forcing term,which motivated development of surface mesoscale system and accompanied formation of secondary cir?culation,both factors are the mechanism to maintain rainstorm.