一次冰雹云形成发展与闪电演变过程分析

2004年4月23日,江西中部和南部出现了大范围的冰雹强对流天气过程。通过分析这次强对流天气过程发生前的天气形势和云图特征,并应用闪电定位系统、卫星和多普勒天气雷达观测资料,对这次过程的闪电特征进行了研究。结果表明,在雹云的形成发展和减弱阶段,每10min闪电频数<60次,正闪电频数明显低于负闪电。在雹云成熟阶段,闪电频数每10min平均值>60次,负闪电频数大于正闪电。在降雹前10min,闪电频数有跃变现象,其正闪增加速率和降雹呈正相关关系,降雹的起始时刻与总闪电和正闪电每10min频数出现较大值的时刻有明显的一致性。

EVOLUTION OF A HAILSTORM AND ITS CLOUD TO GROUND LIGHTNING

There was a hailstorm in the Middle and the South of Jiangxi province on April 23,2004.Based on the data of the lightning location system,Doppler weather radar and satellite,the characteristics of lightning in various periods of the hailstorm lifetime were studied.The results show that the number of lightning per ten minutes is less than 60,and the positive lightning frequency is obviously smaller than the negative one in the periods of generating and weakening.The average value per ten minutes is bigger than 60,and the negative lightning frequency is bigger than the positive one in the mature stage.It is also found that the sudden increase of lightning frequency emerged 10 minutes before hail's falling down,while the positive one increasing rate is directly related to the intensity of hailstorm.The moment of hail's falling down is consistent to that of the maximum value of lightning emerging.