我国中部地貌过渡带的雷电特征

我国中部地貌过渡地区地势复杂,是雷电灾害多发区之一,为了进一步明确该地区雷电的特征,根据卫星的总闪和地面的地闪定位数据资料,通过统计对比,分析讨论了总闪与地闪特征,得到以下主要结论:总闪多年平均分布是西北较少,而东南较多;年总闪数出现极大值的年份恰好是拉尼娜现象强盛年份,或者是弱的厄尔尼诺年;而总闪最小的极小值则出现在ElNio的最强盛年份;地闪的增加往往出现在极易形成不稳定层结的地貌过渡带的核心区域;正负地闪比例与北方有较大差异,而更接近于南方;多数的正负地闪只有一次回击;地面的地闪与卫星的总闪资料在5～9月份都具有较好的一致性。

Lightning Characteristics over the Physiognomy Transition Region in the Middle Part of China

The severe thunderstorms with many lightning flashes often occur in the physiognomy transition region in the middle part of China where the topography is rather complex.In order to identify the nature of lightning in the area,the characteristics of total and cloud-to-ground(CG)lightning are studied with statistical analysis methods by utilizing the data of total and CG lightning from satellites and Direction Finder(DF)respectively,and both kinds of data are compared in the studies.The main results show that average distribution of the total lightning flashes is less over northwest than southeast in the area.The peak annual values of the total lightning are in La Nia or weak El Nio year,while the lowest value is in the strongest El Nio year.The CG lightning flashes are much easily increased over the core area of the physiognomy transition region where the stratified atmosphere is unstable.The ratio of the positive to negative CG lightning flashes is different from the one over north,but much similar to the one over south part of China.The most of the positive and negative CG lightning flashes are just with only one return stroke.The lightning flashes by ground observation system are well consistent with total lightning flashes obtained from satellite from May to September.