湘中地区2010年5月两次暴雨过程的雷达特征对比分析

2010年5月5~6日和5月12~13日，湘中发生了两次区域性暴雨。运用了自动站降水资料、多普勒天气雷达基本反射率和基本径向速度资料以及NCEP提供的FNL资料，分析了这两次暴雨的雷达回波特征，并从水汽和地形两方面分析了两次暴雨的影响因素。结果表明：两次暴雨的环流形势场不同。 “100506”暴雨强降水回波呈带状自西南向东北扫过娄底，而“100513”暴雨强降水回波呈块状自西往东范围逐渐加强；两次暴雨都有逆风区存在，逆风区的范围和强度对应着强降水的范围与强度。两次暴雨水汽主要来自孟加拉湾和南海，“100506”暴雨发生在切变线附近；“100513”暴雨发生在切边线南侧的辐合区内。娄底西部、北部、中部山地的阻挡和抬升作用以及冷暖气流交汇也是暴雨产生的重要原因之一

COMPARISON ANALYSIS OF RADAR FEATURES OF TWO RAINSTORMS PROCESSES IN CENTRAL HUNAN IN MAY,2010

Two regional rainstorms occurred in Loudi between 5th and 13th in May 2010.Radar echo feature,water vapor conditions and terrain factors in these two rainstorms processes were analyzed comparatively based on AWS precipitation data,base reflectivity and base velocity of Doppler weather radar as well as FNL data from NCEP.The results show that they happened with different circulation.The zonal base reflectivity of "100506" rainstorm moved across Loudi from southwest to northeast,and the block base reflectivity of "100513" rainstorm gradually strengthen from west to east.Converse wind region existed and indicated the scope and strength of rainstorm.Water vapor came from the Bay of Bengal and South China Ser,"100513" rainstorm happened near the shear line;"100506" rainstorm happened at the cutting edge in the south of the convergence zone.The block and the uplift of the western,northern and central mountain in Loudi and the intersection of cold and warm air is one of the important factors of these two regional rainstorms.