一次正地闪触发两个并发上行闪电的光电观测  

Optical and Electric Field Observations of Two Concurrent Upward Flashes Triggered by a Positive Cloud-to-ground Flash

作　　者：武斌 吕伟涛[1] 齐奇[1] 马颖[1] 陈绿文[2] 宿志国 吴姗姗 Wu Bin;Lu Weitao;Qi Qi;Ma Ying;Chen Luwen;Su Zhiguo;Wu Shanshan(Laboratory of Lightning Physics and Protection Engineering/State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081;Institute of Tropical and Marine Meteorology China Meteorological Administration,Guangzhou510080)

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室/雷电物理与防护工程实验室,北京100081 [2]中国气象局广州热带海洋气象研究所,广州510080

出　　处：《应用气象学报》2019年第3期257-266,共10页Journal of Applied Meteorological Science

基　　金：国家重点研究发展计划(2017YFC1501504);国家自然科学基金面上项目(41775010;41475003)

摘　　要：广州高建筑物雷电观测站光电同步观测系统于2017年6月16日记录到一次峰值电流达+141 kA的单回击正地闪触发两个并发上行闪电过程。利用高速摄像、普通摄像和电场变化数据分析了触发型上行闪电的始发特征和机理。结果表明:正地闪回击后约0.8 ms内,在距正地闪接地点约3.9 km的广州塔(高600 m)和4. 1 km的东塔(高530 m)分别有上行闪电始发。正地闪回击过程中和大量正电荷以及之后可能有云内负先导朝高塔方向快速伸展造成塔顶局部区域的电场发生突变是两个上行闪电激发的原因。两个上行闪电在353 ms内发生7次回击,其中6次在广州塔上,仅1次在东塔上,且广州塔回击峰值电流平均值(-21. 4 kA)约为东塔回击峰值电流(-7. 3 kA)的3倍,表明广州塔上行闪电通道可能比东塔上行闪电通道伸展至分布范围更广、电荷量(或电荷密度)更大的负电荷区。两个上行闪电先导的二维速率变化范围为9.4×10~4～1.8×10~6 m·s^(-1),平均值为6.9×10~5 m·s^(-1)。Tall objects are easy to trigger upward flashes. They also provide more opportunities for observation of upward flashes and a suitable platform for analyzing the intiation and development of upward flashes. Upward flashes are usually divided into two types, one is self-initiated and the other is triggered by environment, and the latter type is often related to the activity of positive cloud-to-ground (CG) flash. At present, development characteristics and triggering mechanism of the upward lightning channel are mainly studied based on the image of the extracloud lighting channel, the ground electric field change data and radar echo data. Few examples of mutiple upward flashes triggered by the same positive CG flash on different tall objects have been observed, and detailed characteristics of upward flashes are not well understood. On 16 June 2017, a positive CG flash (single stroke, peak current +141 kA) is recorded by the lightning photoelectric synchronous observation system of Tall Object Lightning Observatory in Guangzhou (TOLOG), triggering upward flashes of two nearby super-high-rise objects. Results show that within about 0.8 ms after the return stroke of the positive CG flash, two upward negative flashes intiate from the Canton Tower (600 m high) and the East Tower (530 m high), which are about 3.9 km and 4.1 km away from the positive CG flash, respectively. The initiation of two upward flashes could be caused by combined effects of the return stroke of positive CG flash, its associated continuing current, and the negative leader in the cloud approching to towers. A total of 7 strokes occur in about 353 ms, 6 strokes on the Canton Tower and 1 stroke on the East Tower, and the leader/return stroke sequence on the Canton Tower occur after the leader/return stroke sequence and the attempt leader on the East Tower, i.e., there is no overlapping between strokes of two upward flashes. The average peak current (-21.4 kA) of return strokes of upward flash initiating from the Canton Tower is about 3 times of the p

关 键 词：高建筑物 正地闪 上行闪电 

分 类 号：P412[天文地球—大气科学及气象学] P427.3