基于浙江省三维闪电监测系统的多回击闪电参数的特征分析

为深入了解浙江地区地闪和云闪的雷电活动,基于2019—2020年浙江省三维闪电定位探测资料,分析研究了该地区多回击地闪和云闪相关参数特征。结果表明:两年内浙江省共发生地闪回击数和云闪回击数98万和38万余次,多回击地闪和云闪分别占28.1%和8.01%,其中负闪占总闪比重大于正闪;地闪和云闪频数存在明显的月变化和地域分布,夏季和浙南地区更易发生多回击过程;云闪平均回击次数为1.10次,低于地闪的1.59次。地闪和云闪回击平均强度随回击数的增加而下降,其中正闪下降趋势更为剧烈;超一半的多回击地闪和云闪至少有一次继后回击电流强度大于首次回击电流强度,地闪和云闪继后回击与首次回击强度的比值呈对数正态分布,集中在0～2,其中云闪分布更为集中。地闪和云闪回击间隔时间算术平均值相当,约115 ms,几何平均值地闪明显大于云闪;回击间隔时间呈对数正态分布,其云闪分布更为集中,且集中区域对应的回击间隔时间更小。不同回击次数的云闪和地闪平均间隔时间随回击数增加而减少。地闪和云闪间隔距离分布相似,地闪平均间隔距离明显小于云闪,且分布更为集中。

Characteristic Analyses on Multi-return Stroke of Lightning Parameters over Zhejiang Based on 3-D Lightning Location System Data

In order to deeply understand the physical characteristics of cloud-to-ground (CG) lightning flash and intracloud (IC) lightning flash. The distribution and related parameters of multiple return strokes of CG and IC flashes were analyzed by the lightning data recorded from the three-dimensional (3D) Lightning Monitoring System over Zhejiang. The results show that about 980 thousand CG flashes and 380 thousand IC flashes are occurred from 2019 to 2020. The ratio of multiple stroke CG flashes to total CG flashes and multiple stroke IC flashes to total IC flashes is 28.1% and 8.01%, respectively. And that the ratio of negative flashes is larger than positive flashes. The monthly and spatial distribution characteristics of the IC and CG flashes are obvious, multiple return strokes of CG and IC flashes mainly occur in the southern Zhejiang and summer. The mean stroke number of CG and IC flashes is 1.59 and 1.10. The average current for CG and IC flashes of particular multiplicity has a tendency of decreasing with the stroke order, in which the trend of positive flash decline is more intense. Furthermore, about half of multiple stroke CG and IC flashes have at least one subsequent stroke whose initial peak electric field larger than that of the first return stroke. The distributions of the ratio of the subsequent stroke current intensity to the first return stroke current intensity of IC and CG flashes are both log-normally and the frequency of ratio between 0 and 2 is the most, in which the distribution of IC flashed is more concentrated. The CG and IC flashes time interval arithmetic mean are about 115 ms, which the time interval geometric mean of IC flashes is obviously larger than CG flashes. The distributions of time interval of CG and IC flashes are log-normal. The IC distribution is more concentrated and the time interval in this regional is smaller. Furthermore, the mean time interval has a tendency of decreasing with the stroke order. The distribution of interval distance between CG and IC flashes is similar, and the CG flashes distribution is more concentrated. The mean interval distance of CG flashes is larger than IC flashes.