【摘要】 1998年 4月 2 3日下午在中尺度对流系统 (MCS)的影响下 ,山东潍坊地区出现了一次大范围的冰雹强对流天气。应用闪电定位系统、卫星和雷达观测资料 ,研究了这次降雹过程形成和发展不同阶段闪电的变化特征。分析发现 :雹云在形成发展和减弱消亡阶段 ,每 5分钟闪电频数低于 2 0次 ,且正闪电频数明显低于负闪电 ;雹云在成熟阶段 ,闪电频数每 5分钟平均值大于 2 0次 ,且正、负闪电频数相当 ,而在强降雹前短时会出现正闪电频数超过负闪电现象。此外还发现 ,在降雹前 2 0～ 30分钟闪电频数有跃增现象 ,其增加速率和降雹强度呈正相关关系 ,降雹的起始时刻与总闪电和负闪电每 5分钟频数出现极大值的时刻有明显的一致性。更多还原

【Abstract】 There was a severe hail storm under the influence of mesoscale convective system in Weifang district,Shandong Province on April 23,1998.Based on the data obtained by the lightning location system,radar and satellite,the variation character of lightning in various periods of hail cloud forming and developing was studied.The results show that the number of lightning per five minutes is less than 20,and the positive lightning frequency is obviously smaller than the negative one in the periods of hail cloud forming and weakening.The lightning average value per five minutes is bigger than 20,and the positive lightning frequency is equivalent to the negative one in the mature stage.The positive one is temporarily bigger than the negative one just before the severe hail beginning.It is also found that the sudden increase of lightning frequency emerged in the 20—30 minutes before the hail fall beginning,while increasing rate is directly related to the intensity of hail storm.The moment of hail beginning is consistent to that of the maximum value of lightning emerging.更多还原