陇东地区冰雹云系发展演变与其地闪的关系

THE RELATIONSHIP BETWEEN THE VARIATION OF HAIL CLOUD SYSTEM AND ITS CLOUD TO GROUND LIGHTNING IN THE EAST PART OF GANSU PROVINCE

利用１９９７年设在陇东地区的闪电定位系统及双线偏振雷达资料，分析研究了该地区冰雹云系发展演变及其地闪的关系。结果表明：在降雹前３０ｍｉｎ左右时，每５ｍｉｎ地闪频数陡然上升，降雹前１８ｍｉｎ，每５ｍｉｎ地闪频数平均上升为３．５，每５ｍｉｎ地闪频数的最大值一般是出现在开始降雹前１６ｍｉｎ到前６ｍｉｎ之间，在冰雹云演变的发展、成熟和消散三个阶段中负地闪数远大于正地闪数，并且起着主导作用。冰雹云中心的冰相粒子含量的变化与地闪数变化相对应，间接表明冰雹云起电机制主要以非感应起电机制为主。

Based on the data of the lightning location system and t he dual linear polarization radar in east part of Gansu province, the relationsh ips between the cloud to ground lightning and the variation of the hail cloud sy stem are analyzed. The results show that the number of the cloud to ground light ning per five minutes increase suddenly at 30 minutes before the hailstones fal l, its average value is about 3.5 at 18 minutes before the hailstones fall, it i s not the biggest one when the falling of the hailstones takes place, it always appear between 6 and 16 minutes before the falling, and the negative one is much bigger than the positive one. In three stages of the variation of the hail clo ud, the ice phase particles in the center of the hail cloud increase in the begi nning, then decrease, just like the number of the cloud to ground lightning; Th e non inductive charging mechanism change from strong to weak one.