雷州半岛盛夏闪电活动特征及其与降水的联系

Relationship between the Characteristics of Lightning Activity and Precipitation during Midsummer in the Leizhou Peninsula

利用雷州半岛2007年7、8月常规地面气象观测资料和闪电定位资料,分析了闪电活动与24 h降水量及雨强的关系,结果表明：雷州半岛盛夏地闪频数的最大值中心在其东侧海面上,地闪高发带沿海岸线呈南北向分布;地闪频次存在明显的日变化特征,13：00-18：00为闪电高发时段;无闪电时,有41.3%的降水事件24 h降水量≤1 mm,61.5%的降水事件雨强≤1 mm.h-1;有闪电时相应的事件概率分别为25.9%和37.7%;24 h降水量〉30 mm的事件大多发生在有闪电的情况下,无闪电时极少发生;雨强概率分布的日变化特征不明显;有闪电活动时,雨强均值变化幅度加大。

The rainfall and lightning activity produced by rain events in the Leizhou Peninsula from July to August 2007 are studied. The data consist of 24 h accumulated precipitation and rainfall intensity reported by the surface network and the lightning strokes detected by LD lightning positioning systems. It is found that most of the lightning activity occurs over the eastern maritime area and distributes from north to south near the coastline. There is an obvious change in diurnal distribution of the cloud-to-ground （CG） flash, and occurs most frequently from 13：00 to 18：00. It is found that for almost 41. 3% and 61.5% of the cases in which rain happens without lightning, 24 h and 1 h accumulated precipitation is smaller than or equal to 1 mm, respectively. These two percentages drop to about 25.9% and 37.7% for the cases with lightning. The rainfall events in which 24 h accumulated precipitation is over 30 mm mostly occur with lightning activity. Although lighting activity broadens the amplitude of the average of rainfall intensity, there is no obvious diurnal variation of probability distribution of rainfall intensity.