成都地区地闪时空特征分析

利用XDD03A型闪电定位仪所取得的3年资料,初步研究了成都周边地区地闪特征。地闪中正地闪占绝大多数,其平均强度为6045 A,略高于负地闪的5974 A。地闪强度基本集中在12000 A以下。地闪活动具有明显的日变化,总体呈单峰单谷形式,地闪频次在60以上的峰值时段是18:00~24:00和01:00,频次在10以下的谷值时段是10:00~13:00,夜间闪电活动明显大于日间。正地闪频次日变化趋势和总地闪相同,负地闪频次日变化趋势除一些小波动外,和正地闪、总地闪相同。正负地闪频次的月变化趋势相同,6、7、8月闪电数较多,4、5、9、10月闪电数较少。通过统计分析,发现各月地闪频次和对应的各月降水量有较好的相关性。成都周边地区地闪活动密集,6、7、8月的地闪密度大大超过4、5、9、10月。

Temporal-Spatial Characteristics of Cloud-to-Ground Lightning around Chengdu

The characteristics of cloud-to-ground(CG) lightning flashes around Chengdu is analyzed by means of three-year observational data from the XDD03A lightning location system.It is found that the majority of CG lightning flashes are positive with a mean intensity of 6045 A,slightly higher than that of negative flashes.The intensity of CG flashes is mostly below 12000 A.The daily variation of CG lightning flashes assumes a form of unimodal undulance,with the peak over 60 times from 18:00 to 21:00 and at 01:00 and the valley below 10 times from 10:00 to 13:00.Lightning flashes occur more frequently at night than in the daytime.The tendency of the daily variation of the positive CG lightning flashes is similar to that of total CG lightning flashes and so is that of the negative CG lightning flashes except some slight fluctuations.The tendency of the monthly variation of the number of the positive CG lightning flashes is similar to that of negative CG lightning flashes.Lightning flashes occur more frequently in June,July and August,while less frequently in April,May,September and October.Good correlation between monthly rainfall and corresponding monthly total CG flashes is found.The lightning density around Chengdu is relatively great,much higher in June,July,and August than in April,May,September,and October.