夏季雷州半岛强降水雨滴谱个例分析及降水与闪电相关性统计分析

利用2007年8月在雷州半岛观测雷暴获得的雨滴谱和地闪资料,重点分析了8月6日遂溪、湛江一次雷暴云降水个例的雨滴谱特征,对闪电特征与降水的相关性进行了统计分析。结果表明,遂溪站的雨滴谱谱型多为双峰或多峰型,而湛江站的雨滴谱谱型多呈单峰型分布;平均雨滴谱符合Gamma分布;雨强I10mm/h时发生地闪的频率较高,且发生地闪频率随着距测站的距离减少而增加;随着雨强的增大发生正地闪的概率明显增加;降水过程中的闪电频率和距离校准后闪电电流强度的相关性表明,地闪发生的距离越近,频率越高对应雨滴谱谱宽越宽和降水强度越大。

The raindrop size distribution of a thunderstorm event and the relationship between precipitation and lightning over Leizhou Peninsula in summer

Based on the data of raindrop size distributions(RSDs) and lightening over the Leizhou peninsula in August 2007, this paper analyzed the(RSDs) of a thunderstorm at Suixi and Zhanjiang on 6 August 2007 and the relationship between lightening and precipitation.The results showed that the RSDs were mostly bi-peak or multi-peak spectra at Suixi while they were mainly single-peak spectra at Zhanjiang.The spectra were all fitted with Gamma distribution.The lightning strokes were higher in heavy rain(I>10 mm/h) than in the precipitation with lower rain rate.The strokes of lightning also increased when it got closer to the station in heavy rain(I>10 mm/h).The positive ground flash frequency rose obviously with increasing rain rates.The relationship between lightning frequency and distance-normalized current intensity in the precipitation suggested that a higher occurrence frequency of cloud-ground(CG) lightning in shorter distance was associated with broader raindrop size spectrum and higher rain rates.