Total Lightning Characteristics and Electric Structure Evolution in a Hailstorm

作     者：郑栋 张义军 孟青 吕伟涛 易笑园 

作者机构：Laboratory of Lightning Physics and Protection EngineeringChinese Academy of Meteorological Sciences Tianjin Meteorological Bureau 

出 版 物：《Acta meteorologica Sinica》 (气象学报)

年 卷 期：2009年第23卷第2期

页      面：233-249页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

基　　金：Supported by the Natural Science Foundation of China under Grant No.40875003 the National Basic Research Program of China under No.2004CB418306 

主　　题：lightning activity electric structure non-inductive charging mechanism bidirectional leader 

摘      要：In this paper, total lightning data observed by SAFIR3000 3-D Lightning Locating System was combined with radar data to analyze characteristics of the lightning activity and electric structure of a hailstorm that occurred in Beijing on 31 May 2005. The results indicated that there were two active periods for the lightning activity during the hailstorm process. The hail shooting was found in the first period. After the end of the hail shooting, lightning frequency decreased suddenly. However, more active lightning activities occurred in the second period with lots of them appearing in the cloud anvil region. The peak of the lightning frequency came about 5 min prior to the hail shooting. Only 6.16% of the total lightning was cloud-to-ground （CG） lightning, among which 20% had positive polarity. This percentage was higher than that in normal thunderstorms. In addition, heavier positive CG lightning discharge occurred before rather than after the hail shooting. In the stage of the hail shooting, the electric structure of the hailstorm was inverted, with the main negative charge region located around the -40℃ level and the main positive charge region around the -15℃ level. In addition, a weak negative charge region existed below the positive charge region transitorily. After the hail shooting, the electric structure underwent fast and persistent adjustments and became a normal tripole, with positive charge in the upper and lower levels and negative charge in the middle levels. However, the electric structure was tilted under the influence of the westerly wind in the middle and upper levels. The lightning activity and electric structure were closely related to the dynamic and microphysical processes of the hailstorm. It was believed that severe storms with stronger updrafts were more conducive to an inverted tripolar electric structure than normal thunderstorms, and the inverted distribution could then facilitate more positive CG lightning in the severe storms.