副高边缘暴雨的多普勒雷达回波特征

Analysis of Doppler Radar Echo Feature of Heavy Rain Events at the Edge of West Pacific Subtropical High

利用常规观测资料和多普勒雷达探测资料，对2003-2004年湖南省4次副高边缘暴雨的天气形势和雷达回波特征进行了分析研究。结果表明：4次暴雨过程的副高位置适当，高空有低槽，中低层有低空急流和低涡切变线，地面上有冷锋。在基本反射率图上，低槽暴雨有S-N向的窄带回波特征、冷式切变线暴雨有准W—E向的积层回波特征、暖式切变线有NE—SW向的积层回波特征，但每一次暴雨过程不尽相同。在多普勒速度图上常出现低空急流、冷暖平流、冷锋、逆风区以及高层大风核等特征，并常是几种特征同时出现，有利于强降水产生。

Based on the routine observation data and the Doppler weather radar data, the synoptic patterns and radar echo features of four heavy rainfall events at the edge of western Pacific subtropical high in Hunan from 2003 to 2004 are analyzed. It shows that the position of the western Pacific subtropical high, the upper-trough, the southwest jet stream, low vortex, shear line and cold front in surface are responsible for precipitation. In base reflectivity picture, the heavy rainfall of warm shear line, the heavy rainfall of cold shear line and heavy rainfall of trough are characteristic by narrow band echo feature from south to north, cumulostratus echo feature from west to east approximately and cumulostratus echo feature from northeast to southwest respectively. In Doppler radial velocity picture, there are lowlevel iet, cold （warm） advection, cold front, averse wind region, the upper strong wind core feature and so on. When several features appear at the same time, the heavy rainfall event will likely appear.