“4.17”广东雷雨大风冰雹天气成因分析

Analysis of Causes of Guangdong's Thunderstorm and Hail Happened on April 17,2011

为进一步提高强对流天气的预报水平,利用NCEP的1°×1°再分析资料及气象常规资料,对广东2011年4月17日雷雨大风冰雹过程的天气形势、物理因子及中尺度系统进行综合分析,试图从多角度研究此次强对流天气成因。研究表明:高空槽、中低层切变线及地面冷锋是此次强对流天气的主要影响系统,急流作为暖湿气流的载体,为强对流的产生提供充足的水汽与能量条件,冷空气与高能不稳定的暖空气交汇,是触发不稳定能量释放的机制;大喇叭形的珠江口及地形摩擦作用使大量来自海洋的水汽在珠江口辐合上升,使强对流得以维持;高空辐散与低空的辐合的配置及较强的环境风垂直切变,为雷暴的形成和维持提供非常有利的动力条件,对雷暴单体的形成具有重要作用;同时,雷达图的弓状回波,后侧入流缺口等特征对冰雹落区和降雹时间的预报有很好的指示意义。

Using NCEP 1°×1° reanalysis data and conventionai meteorological data, the circulation, physical ihctors and mesoscale system of thunderstorm in guangdong province on April 17 , 2011 are analyzed. By the analysis we try to reveal the causes of thunderstorm from the multiple perspectives. The research showed that the main influencing system of thunderstorm is upper trough, the low level shear line and the told front The warm vapor with high moisture carried by the jet provides sufficient water vapor and energy he cold mass entered the unsable warm mass with high moisture is the mechanism to release the unstable energy. The large trumpet-shaped Pearl River estuary and the topography friction caused a large amount of water vapor from the ocean to converge at the estuary of the Pearl River to maintain strong convection. The structure of the upper divergence , the lower level convergence and forceful vertical shear of environment wind , these conditions provided the favorable dynamic condition to the formation and maintaining of the thunderstorm, which plays an important role in the formation of reell thunderstorms. At the same time, Doppler weather radar offers a good ref- erence to estimate, the characteristic of Bow Echo and rear inflow notch are good meaning for forecasting falling area and time of haiI from radar.