Temporal and Spatial Distribution of Ground Flash Activity with Environmental Impact Factors Around Fangchenggang City, China

This study investigates the temporal and spatial characteristics of ground flash activity and qualitatively explores its environmental influencing factors using lightning localization system (LLS) data of Fangchenggang City, Guangxi Province, China, from 2009 to 2014. Temporally, the ground flash frequency is positively correlated with the change of air temperature, with rise or fall of air temperature significantly promoting or inhibiting ground flash frequency. Spatially, taking the Shiwan Great Mountain in Guangxi as the dividing line, the southern side of the mountain range exhibits approximately twice the ground flash density of the northern side, revealing a distinct north-south disparities. Additionally, the geometric mean of lightning current amplitude demonstrates notable sea-land disparities, with high values mainly concentrated over the sea. Along the coastline, while Jiangping Town exhibits a ground flash density three times the regional average, the geometric mean (GM) of lightning current amplitudes remains approximately 5 kA lower than the regional baseline. Conversely, regions with lower ground flash frequency tend to have higher lightning current amplitudes. These findings emphasize the significant influence of environmental factors on ground flash activity and underscore the importance of incorporating such factors into the design of lightning protection system.