Analysis of temporal and spatial distribution of CG lightning activity and its relationship with terrain features around Jiuxianshan mountain

The study analyzes the Cloud-to-Ground (CG) lightning location data of the Lightning Monitoring System in Fujian Province from 2015 to 2021. It focuses on examining the temporal and spatial distribution of CG lightning activity within a 20 km radius surrounding the Jiuxianshan meteorological station in a mountainous area. Additionally, it investigates the influence of altitude, slope, and slope aspect on the distribution of CG flash, as well as the characteristics of the current intensity distribution of return stroke. The results indicate a notable difference in the distribution of ±CG flashes. Negative CG lightning activity in the surrounding areas of the meteorological station predominantly concentrates on the northwest and southeast directions of the station, and is most concentrated during the period from 13:00 to 20:00. The distribution of return stroke current intensity exhibits an unimodal pattern, with the intensity mostly distributed within the range of 10–40 kA, accounting for 76.5 %. Among them, the proportion of cases distributed between 10 and 20 kA is the highest, reaching 35.9 %. The analysis considering terrain information reveals a generally positive correlation between the distribution density of negative CG flashes and the slope. The negative CG density is higher on east-facing and southeast-facing slopes.