强雷暴天气的闪电和雷达回波特征个例分析

ANALYSIS OF LIGHTNING AND RADAR ECHO CHARACTERISTICS IN A SEVERE THUNDERSTORM

利用粤港澳闪电定位系统、广州多普勒天气雷达和自动气象站等资料,分析了2017年6月2日发生在广州市中北部的一次强雷暴天气过程的地闪变化特征及闪电与雷达回波特征的关系。(1)本次强雷暴天气是华南一起典型的以西南急流和切变线为环流背景的强对流天气过程。在整个雷暴生命史中以负地闪为主,占69.3%;正闪在雷暴发展的初始和结束阶段占比较大。(2)闪电频数分布与强雷达回波区域存在着较好的对应关系,闪电活动位置稍有提前,地闪频数峰值的时间比雷达回波峰值时间平均提前了11.1 min。(3)回波顶高是产生闪电的先决条件,闪电较多分布在回波顶高9~15 km范围内,地闪频数峰值落后于回波顶高峰值12~18 min。

Based on data from the lightning location system of Guangdong,Hong Kong and Macao,Guangzhou Doppler weather radar and automatic weather stations,this paper analyzes the ground lightning variation characteristics and the relationship between lightning and radar echo characteristics of a strong thunderstorm on June 2,2017 in the north and central part of Guangzhou.The results show that:(1)This thunderstorm is a typical strong convective weather process in southwest China with jet and shear line as circulation background.In the whole life of the thunderstorm,lightning is mainly negative,accounting for 69.3%of the total,whereas lightning flash is mainly positive in the initial and end stages of the thunderstorm.(2)The distribution of lightning frequency has a good correspondence with the strong echo region reported by radar though the lightning activity location is slightly ahead of the location reported by radar;the peak time of ground lightning frequency is 11.1 min ahead the peak time of radar echo.(3)The height of echo top is a prerequisite for lightning occurrence.During this thunderstorm,lightning is mainly distributed in the region of which echo top height ranges from 9 to 15 km,and the peak of ground lightning frequency is 12~18 min later than the peak time of echo top.