反极性云闪的初始击穿特征  

Characteristics of the Preliminary Breakdown in Inverted-polarity Intracloud Lightning Flashes

作　　者：高攀亮 史东东 吴亭 王道洪 纪晓玲[5,6] Gao Panliang;Shi Dongdong;Wu Ting;Wang Daohong;Ji Xiaoling(China Science Skyline Technology Co.,Ltd.,Yinchuan 750000;College of Electrical,Energy and Power Engineering,Yangzhou University,Yangzhou 225001;Key Laboratory of Middle Atmosphere and Global Environment Observation,Institute of Atmospheric Science,Chinese Academy of Sciences,Beijing 100029;Department of Electrical,Electronic and Computer Engineering,Gifu University,Japan,Gifu 501-1193;Key Laboratory of Meteorological Disaster Prevention and Reduction,Ningxia Meteorological Observatory,Yinchuan 750002;Key Laboratory for Meteorological Disaster Monitoring and Early Warning and Risk Management of Characteristic Agriculture in Arid Regions,CMA,Yinchuan 750002)

机构地区：[1]中科天际科技股份有限公司,银川750000 [2]扬州大学电气与能源动力工程学院,扬州225001 [3]中国科学院大气物理研究所,北京100029 [4]日本岐阜大学工学部,岐阜501-1193 [5]宁夏气象防灾减灾重点实验室/宁夏气象台,银川750002 [6]中国气象局旱区特色农业气象灾害监测预警与风险管理重点实验室,银川750002

出　　处：《应用气象学报》2023年第3期324-335,共12页Journal of Applied Meteorological Science

基　　金：宁夏回族自治区重点研发计划重点项目(2020BDE02006);银川市科技创新项目(2022GX08);中国科学院大气物理研究所中层大气和全球环境探测重点实验室开放课题(LAGEO-2022-06)。

摘　　要：基于快天线闪电定位阵列(fast antenna lightning mapping array,FALMA)的观测数据,对2019年8月2日和5日发生于我国宁夏的两次雷暴过程312例反极性云闪的初始击穿(preliminary breakdown,PB)特征进行统计。脉冲参数统计结果显示:PB过程持续时间算术平均值为9.8 ms;脉冲结构由脉冲上升沿、半宽、下降沿和脉冲宽度4个变量表征,算术平均值分别为7.3,4.5,5.6μs和24.7μs。脉冲频率和脉冲间隔的算术平均值分别是5.7ms^(-1)和169.2μs。通道参数统计结果显示:反极性云闪的起始高度平均值为6.9 km。相比于正极性云闪,反极性云闪PB倾向于在弱雷达回波区域起始,雷达反射率因子算术平均值为19.3 dBZ。垂直发展距离和垂直速度平均值分别是2.0 km和2.8×10^(5)m·s^(-1)。PB参数随起始高度变化的结果表明:PB持续时间、垂直发展距离(垂直速度、脉冲频率)与起始高度呈正(负)相关。The intracloud(IC)flashes can be classified into normal and inverted-polarity types according to their initial leader propagation directions.Due to the rare occurrence of inverted-polarity IC flashes with downward preliminary breakdown(PB)processes,the corresponding PB characteristics are much less understood than those in normal IC flashes.Based on the lightning data observed by a low-frequency lightning mapping system FALMA(fast antenna lightning mapping array)deployed in Ningxia,the characteristics of the PB process in 312 inverted-polarity IC flashes are statistically analyzed.The parameters of PB waveforms show that the arithmetical mean(AM)of the PB duration is 9.8 ms.The pulse shape is characterized by rise time,half-peak width,fall time,and pulse width,respectively,with AM values of 7.3μs,4.5μs,5.6μs,and 24.7μs.The pulse rate and pulse interval are 5.7 ms^(-1)and 169.2μs.The statistical results for PB channels show that the inverted-polarity IC flashes are usually initiated at the AM altitude about 6.9 km,obviously higher than the initiation altitude of normal-polarity IC flashes.The difference indicates that there could be an inverted dipolar charge structure in the thunderclouds of Ningxia.The superposition of PB locations on the radar reflectivity suggests that these inverted IC flashes tend to be initiated in the region with radar echoes weaker than normal IC flashes(19.3 versus 27.8 dBZ).The vertical length and speed of PB channels are 2.0 km and 2.8×10^(5)m·s^(-1).Furthermore,PB parameters show significant correlations with the initiation altitude.Specifically,both vertical speed and pulse rate decrease with the initiation altitude,and the correlation coefficients are-0.44 and-0.53,respectively.However,both PB durations and vertical distances show positive correlations with the initiation altitude,with the coefficients of 0.64 and 0.46,respectively.In general,the PB characteristics of inverted IC flashes present both similarities and differences to the PB processes in other flash types.It is

关 键 词：反极性云闪 初始击穿 FALMA 

分 类 号：P427.3[天文地球—大气科学及气象学]