浙江省两套闪电定位系统地闪数据对比

Comparative Analysis of the Cloud-to-ground Lightning Data Between Two Lightning Location Systems

针对2009—2013年浙江省气象部门和电力部门闪电定位系统(lightning location system,LLS)监测的地闪(cloud-to-ground lightning,CG lightning)数据,从时空分布及探测效率等方面对两者进行对比。结果表明:电力部门LLS监测的年平均地闪频次稳定大于气象部门LLS监测的年平均地闪频次。从空间分布看,沿海平原和金衢盆地等平原地带,两者的地闪密度相近;在杭州和衢州交界地区,气象部门LLS监测的地闪密度稳定大于电力的地闪密度;在其他地区(如浙西北、浙中南部和浙南等大部分地区),电力部门LLS监测的地闪密度稳定大于气象部门LLS监测的地闪密度。利用雷暴日数对两者的探测能力对比可知,气象部门LLS对一些较弱雷暴天气过程中的地闪有漏测可能。利用雷击跳闸记录对比分析,电力部门LLS逐年探测效率稳定高于气象部门LLS的探测效率,两者相差约6%。

Comparative analysis of the lightning location data from 2009 to 2013 is conducted by temporal and spatial distribution and detection efficiency,to explore the difference of data collected from two lightning location systems(LLS) of Zhejiang meteorological department and Zhejiang electric power department.Results show that the inter-annual cloud-to-ground(CG) lightning frequency observed by the LLS of Zhejiang meteorological department is stably lower than that observed by the LLS of Zhejiang electric power department.The number of positive CG lightning occupies 3.5%of total CG lightning observed by the LLS of Zhejiang meteorological department,which is also 2%less than that observed by the LLS of Zhejiang electric power department,and both of them are in a reasonable interval.From the viewpoint of spatial distribution,the CG lightning density of two datasets is nearly equal in coastal plain and the JinhuaQuzhou Basin,but the CG lightning density obtained by Zhejiang electric power department is stably more than that of Zhejiang meteorological department in the other areas except in Chun'an which is located in the border of Hangzhou and Quzhou.It is also found that the occurrence of high CG lightning density region in Chun'an observed by LLS of Zhejiang meteorological department is abnormal.Further analysis of the number of monthly mean thunderstorm days obtained by these two LLSs and manual observation indicates that the monthly mean thunderstorm days observed by the LLS of Zhejiang meteorological department is not more than that of manual observations except in summer,when the monthly mean thunderstorm days observed by LLS of Zhejiang electric power department is almost more than that of manual observations every month.It suggests that the LLS of Zhejiang meteorological department does well in detecting strong thunderstorms while the weaker thunderstorms could be missed.Hence,the LLS detective ability of Zhejiang electric power department is better than that of Zhejiang meteorological department.On the other hand,comparative analysis of detection efficiency is made based on the data of accidents of lightning trip-out on Zhejiang Power Grid.It is concluded that the detection efficiency of the LLS of Zhejiang electric power department is around 6%higher than that of Zhejiang meteorological department.