基于雷电定位系统的雷电多回击地闪参数统计及影响因素分析

Parameter Statistics and Influencing Factor Analysis of Lightning Multiple Return Ground Flashover Based on LLS

根据2010—2021年广东省雷电定位系统(lightning location system,LLS)数据,以不同定位站数的筛选方式对多回击地闪参数进行统计,发现随着选取的定位站数增加,多回击地闪的占比、雷电流幅值和时间间隔增加,由此指出:开展多回击地闪次数及占比统计时应选取定位站数S≥2,避免大部分小雷被忽略;开展雷电流幅值统计时应选取定位站数S≥3,确保雷电流幅值精度。对比分析人工引雷时LLS测量的雷电流幅值差异,发现雷电流幅值越大,LLS中能监测到雷电流的定位站数越多,此时LLS测量的雷电流幅值与人工引雷测量结果的偏差越小。选取定位站数S≥3,统计分析多回击地闪中首次回击雷电流幅值与后续回击的关系及其变化趋势,发现首次至后续回击雷电流幅值中值依次递减、回击时间间隔依次递增,但随着回击次数的增加,所有后续回击的雷电流幅值大于首次回击的概率呈现先增大后略减小的趋势,由此提出后续回击雷电流幅值大于首次回击雷电流幅值的概率计算公式。

According to the data of lightning location system(LLS)in Guangdong province from 2010 to 2021,this paper makes statistics on the parameters of multiple return ground flashover by means of the selection of different positioning stations.The statistical results show that with the increase of the numbers of positioning stations,the proportions of multiple return ground flashover,the amplitudes of lightning currents and the time intervals increase.Therefore,it points out that the numbers of positioning stations should be greater than 2 to avoid the majority of small thunder being ignored.When carrying out statistics of lightning current amplitude,the numbers of positioning stations should be equal or greater than 3 to ensure the accuracy of lightning current amplitude.By comparing and analyzing the amplitude difference of lightning current measured by LLS during artificial triggered lightning,it is found that the larger the amplitude of lightning current,the more the numbers of positioning stations can monitor lightning current,and the smaller the deviation between the amplitude of lightning current measured by LLS and the measured result of artificial triggered lightning.Finally,the paper selects the numbers of positioning stations greater than 3 to statistically analyze the relationship between the amplitude of the first return lightning current and the subsequent return lightning current as well as the and changing trend in the multiple return ground flashover.It is found that the median amplitude from the first return lightning current to the subsequent return lightning current decreases successively and the interval of return lightning current increases successively.However,with the increase of the numbers of returns,the probability that the amplitude of lightning current in all subsequent returns is greater than that in the first return,presenting a trend of first increase and then slight decrease.Thereby,the paper proposes the probability formula for calculating the amplitude of lightning current in subsequent returns.