关键词: 云贵高原斜坡过渡带, 冰雹云, 云闪, 地闪, 2σDFRDT跳跃信号

Abstract: Based on the monitoring data of VLF/LF three-dimensional lightning positioning system, MICAPS routine observation data and ground hail observation data, the lightning activity characteristics of a large-scale disaster-causing hail weather process in the slope transition zone of the Yunnan-Guizhou Plateau were analyzed, and the relation between lightning activity and hail falling was discussed. The results are as follows: (1) The stable southern trough in upper level cooperated with the lower level shear line, lower level jet and surface convergence line, which triggered the large-scale hail weather process. (2) The negative ground lightning dominated during the hail weather process, followed by cloud lightning and positive ground lightning. The frequency of total lightning appeared ‘jump increase’ and ‘sharp drop’ phenomena before and after the hail falling in hail area, respectively, and the jump characteristic of lightning frequency change rate more than two standard deviations (2σDFRDT) was obvious before the hail falling, the 2σDFRDT jump signal and peak of total lightning frequency were 20 minutes and 13 minutes ahead of the hail falling, respectively, so two signals had warning indicative significance for hail falling, while the former was better than the later. (3) The spatial distribution of lightning was basically consistent with the moving path of hail cloud, which was an indicator to the development and movement of hail cloud, and the hail areas were mainly located in the right side of lightning position.

Key words: the slope transition zone of Yunnan-Guizhou Plateau, hail cloud, cloud lightning, ground lightning, 2σDFRDT jump signal