青藏高原东部地区雷暴及其地闪活动特征分析

为进一步了解青藏高原地区雷暴及其地闪特征,对2013～2017夏季(6～8月)青藏高原东部地区典型强雷暴过程的地闪和雷达资料进行了综合分析,重点研究了24次以负极性闪电为主的强雷暴过程,分析表明:所有雷暴最大回波顶高均超过7 km,第一次地闪为正地闪的雷暴其组合反射率和回波顶高明显高于第一次地闪为负地闪的雷暴过程。以地闪极性和频数差异将雷暴分为负地闪雷暴、正地闪雷暴、多地闪雷暴三种类型。负地闪雷暴过程中闪电数量较少且大多发生在雷暴成熟阶段;正地闪雷暴过程中闪电数量在几十次左右,主要发生在成熟阶段后期和消散阶段;多地闪雷暴在初始阶段、成熟阶段和消散阶段都有闪电发生,但主要集中在成熟阶段和消散阶段。三类雷暴强反射率中心移动距离和移动速度也有不同,地闪数量多的雷暴比地闪数量少的雷暴有更长的移动距离,负地闪雷暴较正地闪雷暴有更快的移动速度。

Analysis of thunderstorm and its CG lightning characteristics in the eastern Qinghai-Tibet Plateau

Based on the cloud-to-ground(CG) lighning data in the National Lightning Monitoring and positioning system and?radar data, this paper made a comprehensive analysis of the typical strong thunderstorm in the eastern Tibet Plateau in the summer of 2013-2017 (June-August). 24 cases of thunderstorm with mainly negative lightning were analyzed in this article, the results show that the maximum radar echo top of all 24 thunderstorms reached or exceeded 7 km. Thunderstorm whose first CG lightning is positive CG lightning has greater composite reflectivity and radar echo top than whose first CG lightning is negative. In this paper, thunderstorms are divided into three types: negative CG lightning thunderstorm, positive CG lightning thunderstorms and multiple CG lightning thunderstorm. The number of lightning and the period when lightning occurs in the three types of thunderstorms are different. The number of lightning that occured during negative CG lightning thunderstorms is less, mostly occurred during the mature period; The number of lightning that occured during positive CG lightning thunderstorms is about dozens of times, mostly occurred during the mature period and dissipation period; For multiple CG lightning thunderstorms, lightning occured in the development, maturation and dissipation periods, but mainly in the maturation and dissipation periods.The moving distances and moving speeds of strong reflectance center for three types of thunderstorms are also different.A thunderstorm with a large number of lightnings has a longer moving distance than a thunderstorm with a small number of lightnings, and negative CG lightning thunderstorm has a faster moving speed than positive CG lightning thunderstorm.