Statistical analyses of cloud-to-ground flash activities in Hunan Province

The laws of cloud-to-ground flash activities are the important fundamental data of lightning protection engineering, which can provide reference for the selection of transmission line route and for the effectual lightning protection measures. Based on the lighting data of the lightning location system (LLS) in Hunan Province from 2002 to 2010, the probability distribution of lightning current magnitude is analysed in this paper. The temporal and spatial distribution of lightning activities in Hunan Province is acquired by counting the cloud-to-ground flashes in different time and different regions with geographic information system (GIS) and grid method. Statistical results show that there exist obvious differences of cloud-to-ground flashes in different time and different regions for the lightning activities in Hunan Province. The lightning activities in some regions are intensive and the cloud-to-ground flash density reached 6.9 flashes per square kilometer per year. The probability distribution of lightning current magnitude in Hunan Province accords with a lognormal distribution approximatively.