一次春季区域性暴雨过程诊断分析

2009年5月9日08时～10日08时，长治出现了春季历史罕见的区域性暴雨天气，给农业、交通和电力等带来严重影响。通过对500hPa环流形势特征，700hPa切变系统，物理量场的相对湿度、散度经向剖面、Ki指数平均场及fy-2c红外卫星云图的综合分析，得出结论：南支槽是这次暴雨天气的主要形势。700hPa切变激发出强对流云带，在缓慢东移过程中造成暴雨天气。强降水期间，相对湿度〉80％的湿中心抬升至150hPa，最大对称的湿中心与暴雨落区近于一致，而且低层幅合，高层幅散呈现出较为明显的对称结构，中低层大气一直处于不稳定状态。

Diagnostic Analysis of One Time Regional Heavy Rain in Spring

There was regional heavy rain in Changzhi city at 8 am on May 9 to 8 am on May 10,2009. It was very rare in spring and seriously affected the agriculture, electricity and traffic. The circulation flow situation features of 500hPa, the shear system of 700hPa and the relative moisture of physical quantity field, the meridional profile of divergence, the average field of Ki index and the infrared image of FY-2C were analyzed. The results showed： the south branch trough was the main situation of the heavy rain. The strong convective cloud was occurred by the shear of 700hPa. There was the heavy rain when it moved eastward slowly. During the heavy rain, the humidity center where the relative humidity more than 80% uplifted to 150hPa. The largest symmetrical humidity center kept consistent with heavy rain area. The low convergence and high divergence showed obvious symmetry and middle and low level atmosphere had been in instability.