Abstract:

Based on the cloud-to-ground (CG) lightning data collected by the lightning location system of Power Department during 2005-2014, the spatial and temporal distribution characteristics of the CG lightning flashes and lightning current intensity over Beijing, Tianjin and Hebei were analyzed. The results are showed as follows: the positive CG lightning in the area of Beijing, Tianjin and Hebei was 7.33% of the total CG lightning, the ratio was higher than He’nan’s 3.16%, but less than that of the Inner Mongolia plateau (9.60%). The CG lightning mainly appeared in summer, which accounted for 90.0% of the whole year. In spring and autumn, the percentage of positive flash was higher than that in summer. The ground flash occurred mainly from 15:00 to 19:00, and the maximum value appeared at 16:00, but the peak of positive lightning occurred one hour late. More than 50% of the ground lightning current intensity concentrated from 20 to 45 kA, the average current intensity of negative lightning was 40.46 kA, and the average current intensity of the positive ground flash is 1.8 times more than that of the negative ground flash. The average lightning current intensity was largest in March and it was greater in the morning than that in the afternoon. The high density area of the CG lightning mainly concentrated in mountains and plains transition zone of the southern foot of the Yanshan Mountain and the eastern foot of the Taihang Mountain, the underlying surface with sufficient water vapor and wetland area, the relative population concentration city center area. The lightning with current intensity greater than 80 kA mainly distributed in the southeast coastal of Beijing, Tianjin and Hebei, the middle-east plain of Hebei Province, the northwest Zhangjiakou and north Chengde. The bigger the lightning current intensity was, the smaller the lightning density was. Due to Tangshan, Baoding and Cangzhou are all in the high value area of ground flash density and lightning current intensity, so the design of lightning protection engineering should be strengthened in these areas.

Key words: Beijing, Tianjin and Hebei, the CG lightning density, the CG lightning current intensity, temporal-spatial distribution

摘要：

基于河北省电力部门2005—2014年16站闪电定位资料，对京津冀地区地闪频次和雷电流强度的时空分布特征进行统计分析。结果表明，京津冀地区正地闪占地闪总数的7.33%，该比率高于河南的3.16%，低于内蒙古高原的9.60%。地闪主要出现在夏季，占全年的90.0%；春、秋两季，正地闪所占比率高于地闪频繁的夏季。地闪主要出现在15:00—19:00，最大值出现在16:00，其中正地闪的峰值比负地闪晚1 h。该地区50%以上的地闪雷电流强度集中在20~45 kA之间，其中负地闪与正地闪的平均雷电流强度分别为40.46 kA、74.16 kA，正地闪的平均雷电流强度是负地闪的1.8倍。3月的平均雷电流强度最大；上午的平均雷电流强度大于下午。地闪高密度区主要集中在燕山南麓和太行山东麓迎风坡面的山区与平原过渡区、下垫面水汽充足的水体和湿地区域以及人口相对集中的城市中心区；雷电流强度>80 kA的闪电主要分布在京津冀地区的东部沿海、河北中东部平原、张家口西北部以及承德北部，且闪电强度较大的地区闪电密度较小。唐山、保定、沧州地区处于地闪密度和地闪雷电流强度的高值区，该区域在建设工程的选址和防雷装置设计中应充分重视并加强对雷电灾害的防御措施。

关键词: 京津冀地区, 地闪密度, 地闪强度, 时空分布