云南西双版纳地区闪电活动特征

应用2017—2018年云南省VLF/LF三维闪电定位数据和1987—2006年云南省人工雷暴日观测数据,运用数理统计、空间插值等方法分析"雷都"西双版纳闪电活动的时空分布特征,运用网格法将闪电定位数据转化为网格雷电活动日,研究人工观测雷暴日与闪电定位监测资料的相关性。结果表明:西双版纳地区雷电活动从3月就开始逐渐增多,峰值出现在7—8月。就闪电频次而言,云闪少于地闪、正闪少于负闪,正地闪明显多于云南省其他地区。11月闪电强度较大,但频次较少;7月闪电频次较多,但强度较小。云闪多发生在8 km以下,平均高度为4.914 km。地闪和云闪密度分布一致,北部高而南部和东西部低;云闪的强度明显高于地闪,但在空间分布上均是北部弱而南部和东西部强。人工观测雷暴日与网格雷电活动日的逐月分布特征较一致。研究还表明:西双版纳在云南省范围内是人工观测雷暴日最多区域,也是网格雷电活动日最多区域。

Characteristics of lightning activity in Xishuangbanna, Yunnan Province

Based on the three-dimensional lightning location data of VLF/LF in Yunnan Province from 2017 to 2018 and the data of artificial observation thunderstorm days in Yunnan Province from 1987 to 2006,and using mathematical statistics,spatial interpolation and other methods,this paper studied the spatial and temporal distribution characteristics of lightning activity in Xishuangbanna area,known as a thunderstorm capital.The grid method was used to transform the lightning location data into a grid lightning activity days,to study the correlation between artificial observation thunderstorm days and lightning location monitoring data.Results show that the lightning activity in Xishuangbanna area begins to increase gradually from March,and the peak appears from July to August.The lightning frequency of intra-cloud flash is less than that of cloud-to-ground flash,the lightning frequency of positive flash is less than that of negative flash,and the lightning frequency of positive cloud-to-ground flash in Xishuangbanna area is significantly more than that in other areas of Yunnan Province.In November,the lightning intensity is larger,but the frequency is less.In July,the lightning frequency is more,but the intensity is smaller.Most intra-cloud flashes occur below 8 km,with an average height of 4.914 km.The density distribution of cloud-to-ground flash and intra-cloud flash is the same,higher in the north and lower in the south and east-west.The intensity of intra-cloud flash is significantly higher than that of cloud-to-ground flash,but the spatial distribution is weak in the north and strong in the south and east-west.The monthly distribution characteristics of the observed thunderstorm days are consistent with those of the grid lightning activity days.The study also shows that Xishuangbanna is the area with the most observed thunderstorm days and the area with the most grid lightning activity days in Yunnan Province.