雷暴天气过程中降水结构与闪电活动特征个例研究

Characteristics of Precipitation Structure and Lightning Activities during a Thunderstorm Process

为深入分析四川雷暴天气过程中降水和闪电活动特征,运用统计与对比方法,对四川东南部一次雷暴过程中闪电活动及降水结构之间的特征进行研究。结果表明,强降水易发生在低层辐合,高层辐散的流场中,局部地区最大降水强度发生在2~5km高度。降水开始1h后,地闪频数达到最高,地闪主要以负地闪为主,正地闪不活跃。对闪电活动与亮温分布关系知,闪电活动主要发生在低于220K降水云内,闪电活动发生的区域与降水落区一致。对总闪与地闪的分布知,负地闪主要分布在总闪的外围。通过对四川雷暴过程的研究,对雷暴预报有一定的指导意义。

To better understood the characteristics of precipitation and lightning activities during a thunderstorms in Sichuan, by using the statistical and contrast methods, the features of the lightning activity and precipitation structure during a thunderstorm occurred in the southeastern Sichuan are analyzed. The results show that the heavy rainfall occurred in the flow field with low-level convergence and upper-level divergence, and the height of the local maximum precipitation zone located between 2 km and 5 kin. After one hour of precipitation, the frequency of lightning flashes began to achieve the maximum, and the ground flashes were mainly negative CG （cloud to ground） flashes, and there were few positive CG flashes. According to the relationship between lightning activity and brightness temperature distribution, it is known that lightning activity occurs mainly in precipitation clouds with temperature being less than 220 K, and the areas of lightning activity are in agreement with precipitation areas. From the distribution of the total flashes and CG flashes, it can be known that negative CG flashes are distributed outside of the total flash area, and IC （intracloud） and CG flashes together impacted on the occurrence of lightning activities in the cloud system. The findings are useful to thunderstorm forecasting.