白云机场一次强对流冰雹过程的闪电特征

Lightning Characteristics During a Severe Convective Hail at the Baiyun Airport

采用广东省VLF/LF三维闪电定位资料和白云机场雷达数据对2019年2月21日一次强对流伴冰雹过程的闪电特征进行统计分析。结果表明:冰雹云不同发展阶段闪电的频次,强度明显不同。冰雹云成熟阶段,对流增强,闪电频次快速增大,云顶抬升,正电荷中心强度增大,对冰雹的出现有指示作用。降雹区的正闪电总频数为32次,负闪电总频数为123次,正负闪电强度不大,在-20~20 kV/m。冰雹云内雹和冰晶的碰撞通常使得冰雹获得负电荷,由于雹暴内存在大量的雹粒子,有利于负电荷区的形成,因此降雹区域主要都是负闪电。

Using VLF/LF three dimensional lightning location data of Guangdong province and radar data of the Baiyun Airport, this work performs a statistical study of the lighting characteristics associated with a severe convective hail process. The result is shown as follows. The frequency and intensity of lightning varied significantly as the hail cloud evolved. As it matured, convection intensified, lightning frequency increased rapidly, cloud top lifted and the central intensity of positive electric charges increased, indicating the occurrence of hail. In the hail zone, there are a total of 32 positive and 123 negative strikes of lightning but the intensity is mild, between-20 and 20 kV/m. Usually, the collision between the hail and ice crystal within the hail cloud negatively charged hail particles, which exist within a hail storm in large number. Therefore it is conducive of the formation of a negative electric charge zone, making the lightning within the hail zone predominantly negative.