利用SAFIR资料对北京及其周边地区地闪参数的特征分析  

Characteristic Analyses on Cloud-to-Ground Lightning Parameters over Beijing and Its Surrounding Areas Based on SAFIR Data

作　　者：李京校[1,2] 郭凤霞[2] 沈永海[3] 李家启[4] 宋海岩 肖稳安[2] 

机构地区：[1]北京市避雷装置安全检测中心,北京100089 [2]南京信息工程大学,江苏南京210044 [3]北京市气象局大气探测技术保障中心,北京100089 [4]重庆市气象局,重庆400700

出　　处：《高原气象》2013年第5期1450-1459,共10页Plateau Meteorology

基　　金：国家自然科学基金项目(40930949;41375039);公益性行业科研专项(GYHY201006005;GYHY201306069)

摘　　要：利用2005—2007年北京及其周边地区SAFIR3000闪电定位资料，分析了该地区地闪相关参数特征。结果表明，该地区正地闪平均电流为33．43kA，负地闪为-29．57kA；正、负地闪电场变化波形平均上升时间分别为8．70肛s和5．11fIS，下降时间分别为23．52μs和28．37μs，两者上升、下降时间的月变化均呈反相关关系；地闪平均回击次数为1．57次，其中正、负地闪的平均回击次数分别为1．19次和1．64次，观测到的地闪最大回击数为13次。在正、负地闪中，单次回击闪电比例分别为87．24％和65．22％；地闪回击间隔时间呈准正态分布，集中在40～60ms之间的次数最多，占总次数的23．43％，平均间隔时间为65．03ms，最大为426．8ms。最小为1.7ms；地闪总回击持续时间为0．03～948．4ms；归一化到100km后的正地闪首次回击辐射场场强为5．29V·m-1，负地闪为6．09V·m，正地闪继后回击场强为4．48V·m，负地闪为6．24V·m。Based on the lightning location data of SAFIR3000 in Beijing and its circumjacent regions from 2005 to 2007, the related parameters of cloud-to-ground （CG） lightning were analyzed. The results show that the average current of positive CG lightning is 33.43 kA and negative CG lightning is --29.57 kA. The average rise time of electrical field waveforrn of positive and negative CG lightnings are 8.70μs and 5.11 μs, respectively. And that the decay time is 23.52μs and 28.37μs, respectively. The monthly varia- tions of rise and fall time have an inverse correlation relationship. The mean stroke number of lightning is 1.57 timer, of which positive CG is 1.19 times and negative CG is 1.64 times. The maximum stroke num- ber is 13 times. The single-stroke flashes of total positive CG number is 87. 24% and negative CG is 65.22%. The distribution of time interval of return strokes is log-normally and the frequency of time inter- val between 40 ms and 60 ms is the most, accounting for 23.43% of the total number. The mean time in- terval is 65.03 ms and the maximum value is 426.8 ms while the minimum value is 1.7 ms. The duration time of CG lightning is from 0.03 to 948.4 ms. Normalized to 100 kin, the radiation field of first return stroke of positive CG is 5.29 V· m-1 while negative CG is 6.09 V· m-1 , and the following stroke of posi- tive CG is 4.48 V · m-1 while negative CG is 6.24 V · m-1.

关 键 词：地闪 上升 下降时间 回击次数 回击间隔 辐射场场强 

分 类 号：P427.3[天文地球—大气科学及气象学]