青藏铁路沿线闪电活动的时空分布特征

Temporal and Spatial Distributions of Lightning Activities along Qinghai-Xizang Railway

利用搭载于卫星上的闪电探测仪所获取的8年闪电资料,对青藏铁路沿线闪电活动的时空分布进行了研究。结果表明,青藏铁路沿线的闪电活动呈现出明显的季节变化和日变化。青藏铁路沿线的闪电活动主要发生在4～9月,其中以5～7月最为频繁,到10月份迅速消亡,而且闪电分布在南北向上变化较明显;青藏铁路沿线闪电活动在12:00～16:00(地方时,下同)最易发生。日闪电密度峰值出现在15:00左右。闪电密度的空间分布以那曲为最大,分别向南、北减小。另外,2003年夏季的地面观测资料还表明,那曲地区在傍晚还有一闪电活动峰值。

The temporal and spatial distributions of lightning activities along the Qinghai-Xizang railway are analyzed by using 8-year satellite-based data. The result indicates that the lightning activity along the Qinghai-Xizang railway hasobvious seasonal and diurnal variations. The lightning activities mainly occur from April to September, but disappear in October, and the most active month for different places is from May to July. The diurnal variationof lightning activities shows that the lightning along the Qinghai-Xizang railway more frequently occur between 12:00～16:00 (local time). The value of the flash density is the highest in Naqu, and decreases gradually southward and northward along the Qinghai-Xizang railway. In addition, the data analysis result from ground-based observation indicates the lightning activities showing a sencond peak at 19:00 in Naqu.