云南闪电活动的时空分布特征

Temporal and Spatial Distribution Characteristics of Lightning Activity over Yunnan Province

利用1998-2013年TRMM卫星上携带的闪电探测仪(LIS)监测的闪电资料以及云南6个气象站降水观测资料,分析云南闪电活动的时空分布特征及其与降水量的关系。结果表明:(1)云南地区平均闪电密度为4.7 fl·km^-2·a^-1,闪电密度分布与地形密切相关,自西北向东南呈"V"字型带状增大,滇南的西双版纳、普洱东南部和中越边境的闪电活动最为活跃,最高值为30.6 fl·km^-2·a^-1。(2)闪电活动具有明显的季节变化和日变化。春、夏季闪电活动明显多于秋、冬季,其中春季闪电活动主要发生在滇南,而夏季则在滇东。滇北闪电活动的月分布呈单峰型,峰值在7月或8月,且闪电密度与降水量有较好的相关性,而滇西、滇南和滇东南则呈双峰型,峰值在4月,次峰值在7月或8月,闪电密度与降水量的相关性较差。云南大部地区闪电易发生在当地时间16:00-20:00,而密度高值区的闪电活动多发生在夜间。(3)云南闪电活动明显受地形和海拔高度影响,且与季风密切相关。

Based on lightning density grid data of lightning imaging sensors(LIS) on TRMM satellite and precipitation data at six weather stations of Yunnan Province during 1998-2013, the spatial and temporal distribution characteristics of lightning activities over Yunnan Province and its relationship with precipitation were analyzed. The results are as follows:(1) The mean lightning density over Yunnan Province was 4.7 fl·km^-2·a^-1. The distribution of lightning density was closely related with terrain, and it gradually increased from northwest to southeast with ‘V’ zonal shape. The lightning over Xishuangbanna, southeastern Puer and the border between China and Vietnam of southern Yunnan was active, and the maximum was 30.6 fl·km^-2·a^-1.(2) The lightning activity had obvious seasonal and diurnal variation over Yunnan. The lightning activity in spring and summer was obviously more than that in autumn and winter, and it mainly occurred over southern Yunnan in spring and eastern Yunnan in summer. The monthly distribution of lightning activity appeared typical single peak pattern over northern Yunnan, the peak occurred in July or August, and the monthly lightning density was well related with monthly precipitation. However, the monthly distribution of lightning activity showed double peaks pattern over western, southern and southeastern Yunnan, and the peaks were in April and July or August, respectively, but the correlation between lightning density and precipitation was poor. The lightning over most regions of Yunnan occurred from 16:00 LT to 20:00 LT, and it usually occurred in the nighttime over high density areas.(3) The influence of terrain and altitude on lightning activity was significant over Yunnan, and lightning activity was closely related with monsoon.