京、津、冀地区地闪特征的统计分析

Statistic Analysis on Cloud-to-Ground Lightning Characteristics over Beijing,Tianjin and Hebei Province

京、津、冀地区地闪的区域特征十分明显,利用该地区2004年的地闪的定位资料,通过分析得到以下主要结论:(1)正地闪占总闪的比率为10.86%,而各地区正地闪占总地闪的百分率与相应地闪产生地区的中心纬度之间都存在着很好的线性关系。由于与中、低纬度地区相比,高纬度地区雷暴云整体高度发展得较低,雷暴云中主正电荷区域的位置也较低,因此高纬度地区较中、低纬度地区的正地闪发生得多。(2)雷暴以7月份为最多,且7月份地闪次数的逐日分布较均匀。(3)地闪在空间分布上有4个相对较为集中的区域,这些区域主要是山地的迎风坡、或下垫面水汽的充足处、或人口相对集中的城市中心区。

Based on the cloud-to-ground （CG） data collected by the lightning detection system in North Power Network of China in 2004, the characteristics of CG lightning over Beijing, Tianjin and Hebei province in China are analyzed. The results show as follows. （ 1 ） The percentage of positive CG lightning flashes is 10. 86%, while the relationship between the percentage of positive CG lightning flashes and the center latitude of the area with CG lightning flashes is linear in areas with CG lightning. Compared with low and middle latitude areas, the heights of thunderstorm clouds and their main positive charge centers are lower in high latitude areas, thus more positive CG lightning flashes are produced there. （2）The maximum number of lightning days is in July, and lightning occurs almost every day. （3） CG lightning flashes are mainly concentrated in 4 areas, where are windward slope, the underlying surface with abundance water vapor, or cities with dense population.