青藏高原东北部闪电M变化多参量观测  

The multi-parameter observation of lightning M changes in northeastern part of the Qinghai-Tibet Plateau

作　　者：武斌[1,2] 张广庶[1] 王彦辉[1] 李亚珺[1] 范祥鹏[1] 余海[1] 张荣[1] 

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,兰州730000 [2]贵州省防雷减灾中心,贵阳550002

出　　处：《物理学报》2013年第18期523-537,共15页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:41075002;40775004);国家自然科学基金重点项目(批准号:41030960);公益性行业科研专项(批准号:GYHY201006005-03)资助的课题~~

摘　　要：利用闪电光通道高速摄像、地面电场变化和峰值辐射强度同步资料,对比分析了负地闪连续电流阶段和人工触发闪电放电过程中M变化特征.结果表明,通道亮度资料能够辅助地面电场波形来准确判断是否为真实的M过程.在经典M变化产生前及其过程中会产生很多快速电场变化MP(称为预M变化)变化,大量MP促成了M变化.MP变化和K变化在脉冲特征上没有太多差别,产生的物理机制是相似的.MP变化是连续电流阶段快速电场变化,是击穿过程引起的电荷快速流动的结果,并伴有通道突然增亮和高强度辐射.M变化脉冲波形多数为单极性,有正有负,少数呈现不规则变化,持续时间在0.1 ms之内.而经典M变化的U形结构只适用于近闪,波形是静电场所致,持续时间约0.2—0.8 ms.MP和K变化都是击穿所致,只是MP变化有电荷流入原回击通道,而K变化没有.The M change characteristics in continuing current process ot negative cloud-to-ground llglatnlng discharge and artlticlally trig- gering lightning discharge are comparatively analyzed using the synchronous data of optical channel high-speed video camera pictures, electric field changes on ground and the peak very high frequency radiation. The results indicate that M process could be identified accurately from synchronous data of optical channel luminance and electric field changes on ground. There are lots of rapid changes of electric field （MP） prior to and during classic M change. And the M changes caused by lots of MP changes. There is mostly no difference in waveform characteristics between M changes and K changes and their generated physical mechanisms are similar. MP change is a rapid change of electric field corresponding to the rapid flow of charge caused by the breakdown process in the stage of continuous current process and accompanied with channel sudden brightening and high intensity radiation. Most of the M changes are unipolar, positive or negative and a few are irregular and last within 0.1 ms. Only M change in close lightning discharge exhibits a classic U-shaped structure because of its waveform mostly caused by static electric field, and its duration is about from 0.2 to 0.8 ms. MP and K changes are all caused by the breakdown. The difference between MP and K changes is that the electric charges flow into the original return stroke channel in the process of MP change, but not in the process of K change.

关 键 词：青藏高原 M变化 MP变化 K变化 

分 类 号：P427.32[天文地球—大气科学及气象学] P412.1