双接地负地闪VHF辐射源放电通道和光学通道的对比分析  

Comparative Analysis of VHF Radiation and Optical Channel of the Negative Cloud-to-Ground Lightning Flash with Two Striking Point

作　　者：武斌[1] 张广庶[1] 王彦辉[1] 李亚珺[1] 张彤[1] 范祥鹏[1] 吕伟涛[2] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所寒旱区陆面过程与气候变化重点实验室,甘肃兰州730000 [2]中国气象科学研究院雷电物理和防护工程实验室,北京100081

出　　处：《高原气象》2013年第2期519-529,共11页Plateau Meteorology

基　　金：国家自然科学基金项目(41075002;40775004;41175001);国家自然科学基金重点项目(41030960);公益性行业科研专项(GYHY201006005-03)共同资助

摘　　要：利用闪电VHF辐射源三维定位和闪电光通道高速摄像同步资料,对一次双接地负地闪放电通道作定位和亮度特征进行对比分析,并仔细分析了其通道发展和连接,详细讨论了一次负地闪双接地的形成过程。结果表明,在预击穿阶段,通道击穿作用很强,但电流小,其载体主要是雪崩电荷;在回击激发阶段,通道电流迅速增大,其载体除了雪崩电荷外,还有大量来自云内电荷区的电荷。在整个过程中,主通道有较高亮度(云外),即主通道中有较强电流运动,而分叉通道电流较弱。研究表明近地面向上发展的辐射源可能是源于地面尖端产生的向上先导。The VHF radiation and optical channel in a negative lightning have been comparatively ana- lyzed by the synchronous data from 3D location system of lightning VHF radiation pulses and high-speed Camera system. The synchronous brightness data of channel complements current characteristics of VHF radiation source channel outside the cloud. The results show that the intensity of breakdown is great in the preliminary breakdown process, but the current in the channel is low, and the carrier is mainly avalanche of the charge. The current in the channel increase rapidly in return strike, and the carrier in addition to avalanche charge, there are a lot of cloud charge region from the charge. Throughout the process, the main channel has a higher brightness （outside the cloud）, that is, there is a strong current movement in the main channel, and branching channel current is weak. The development and connection of its channels were analyzed carefully, and the formation process of two striking point in a negative flash was discussed in detail. There are upper radiation sources near the ground which may be result from upward leader from the tip.

关 键 词：负地闪 双接地 VHF辐射源通道 高速摄像 上行先导 

分 类 号：P427.3[天文地球—大气科学及气象学]