Abstract: Based on the data of CG (Cloud-to-Ground) lightning observed by a lightning localization system and thunderstorm observed from 2007 to 2015,the distribution characteristics of lightning in Beijing,Tianjin,and Hebei province were analyzed.The results indicate that the total number of the thunderstorms observed by meteorological observers is different from that of CG lightning observed by the lighting localization system,while the temporal distributions of them are consistent.The thunderstorm data observed by the observers at the surface can only be used to reflect the basic concept of the thunderstorm days due to the limitation of the observation technical standards.By contrast,the CG lightning data observed by the lightning location system are closer to the real lightning distribution.The percentage of the number of PCG (Positive Cloud-to-Ground) lightning to that of TCG (Total Cloud-to-Ground) lightning is 7.8% in Beijing,Tianjin,and Hebei province from 2007 to 2015.This percentage is different in different seasons and regions.Unlike those of TCG and NCG (Negative Cloud-to-Ground) lightnings,the distribution of monthly PCG lightning is relatively uniform.There are no significant differences in the daily variation among TCG,PCG and NCG lightnings.The CG lightning generally appears at the transition zones between mountains and plains and the joint regions of land and ocean in Beijing,Tianjin,and Hebei province.

Key words: Cloud-to-ground lightning, Lightning localization system, Manual observation, Lightning density