多回击负地闪先导通道的辐射和光学特征  

Radiation and Optical Characteristics of the Negative Cloud-to-Ground Lightning Flash with Multiple Return Strokes

作　　者：余海[1,2] 张广庶[1] 李亚珺[1] 王彦辉[1] 武斌[1,3] 张荣[1,2] 吕伟涛[4] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000 [2]中国科学院大学,北京100049 [3]贵州省防雷减灾中心,贵州贵阳550002 [4]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3期894-903,共10页Plateau Meteorology

基　　金：公益性行业科研专项(GYHY201006005-03);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)共同资助

摘　　要：利用闪电VHF窄带干涉仪辐射源定位系统和高速摄像系统,对青海大通地区一次有5次回击的负地闪放电过程进行了同步观测,对比分析了通道传输过程的辐射和光学特征。结果表明,光学通道亮度能补充VHF干涉仪定位先导通道的电流特征,VHF干涉仪定位弥补了光学设备拍摄弱放电和云内流光通道的不足;在通道分枝结构上,干涉仪定位的通道和光学通道呈现出很好对应。干涉仪定位分枝通道的辐射源点较明显,但分枝光学通道的出现明显落后于干涉仪定位辐射源通道。对用两种不同观测手段探测的先导通道进行速度计算,发现两者计算的直窜先导和直窜梯级先导速度量级一致,均为106 m·s-1,但干涉仪在时间的获取及精确量化上有优势,干涉仪定位计算先导速度的精确度高于光学通道定位。A negative cloud-to-ground lightning flash with five return-strokes which occurred at Datong of Qinghai Province has been observed synchronously by using VHF narrowband radio interferometer and the high-speed video camera system. The characteristic of radiation and optics of lightning discharge channel has been analyzed. The results indicated that the optical channel brightness could supply the current char- acteristics of leader from the observation of interferometer, and interferometer observation could make up the weakness of optical equipment shoot weak discharge process and the lightning discharge in intracloud. The structure of channel that has been observed by interferometry and optical equipment is matched well. The radiation sources of the branch channel of interferometer observation are obvious, but the optical channel of branch appeared obviously later than the locating channel of interferometer with visible radiation sources. The magnitude of velocity of dart leader and stepped-dart leader is 106 m · s-1 using above two different calculated devices. However, interferometer has an advantage in acquiring time data and accurate quantification than the optical device. The velocity definition of the leader acquired by interferometer is higher than that of optical observation.

关 键 词：多回击负地闪 VHF干涉仪定位 高速摄像 直窜先导 辐射和光学特征 

分 类 号：P427.3[天文地球—大气科学及气象学]