雷暴闪电活动特征研究进展

RESEARCH PROGRESS OF LIGHTNING ACTIVITY IN THUNDERSTORMS

关键词:  闪电  雷暴  灾害性天气  台风

Key words:  lightning  thunderstorm  severe weather  typhoon

摘要:

从一般雷暴、灾害性雷暴和台风的闪电活动特征以及雷暴闪电尺度特征四个方面对相关研究进行梳理。一般雷暴通常具有正常极性电荷结构，云/地闪比例在3左右（中纬度地区），地闪中正地闪占比为10%左右，负地闪位置往往更集中于对流区。灾害性雷暴倾向具有活跃的云闪，低比例的地闪，易出现反极性电荷结构，正地闪比例偏高。闪电活动与灾害性天气现象之间存在关联性，部分雹暴过程具有两次闪电活跃阶段。台风中大部分闪电发生在外雨带，眼壁/外雨带闪电爆发很可能预示气旋强度的增强以及路径的改变。由闪电持续时间、通道空间扩展所表征的闪电尺度与雷暴对流强度相关。弱对流雷暴或雷暴的弱对流区域可能由水平扩展、垂直分层的电荷分布形态主导，闪电频次低，闪电空间尺度大；强对流雷暴或雷暴的强对流区域可能由交错分布的小电荷区主导，闪电频次高，闪电尺度小。

Abstract:

In this paper, we summarized relevant studies from four aspects, i.e., lightning activity in typical thunderstorms, severe thunderstorms, and typhoons and lightning flash size. The typical thunderstorms usually have a normal charge structure. The ratio of intracloud (IC) lightning to cloud-to-ground (CG) lightning is approximately 3 in middle latitudes, and positive CG (PCG) lightning approximately accounts for 10% of the total CG lightning. Negative CG lightning tends to occur in convective regions. Severe thunderstorms tend to have high-frequency IC flashes and low proportion of CG flashes and feature a relatively greater proportion of PCG flashes associated with the inverted charge structure. There is a correlation between lightning activity and severe weather events. Some hailstorms contain two active-lightning stages. In typhoon, lightning tends to predominantly occur in the outer rainbands. The outbreak of lightning within the eyewall and inner core is likely to indicate an increase in typhoon intensity or a change in path. There is a correlation between the intensity of thunderstorm convection and the lightning flash size represented by flash duration and channel expansion. Weak convective thunderstorms or weak convective areas of thunderstorms may be dominated by horizontally extending and vertically layered charge distribution patterns and feature low-frequency and large lightning flashes. Strong convective thunderstorms or strong convective areas of thunderstorms may be dominated by interlaced small charge regions and feature high-frequency and small lightning flashes.