Abstract:

Based on the ground lightning location data and 30-m precision elevation data in Changsha area from 2009 to 2018, the spatial distribution of ground lightning parameters was analyzed using mathematical statistics and regression analysis, and an annual average return strike frequency model and an average current intensity model for ground lightning per unit area were established based on surface factors. The results showed that ground lighting strikes mainly occur on plains and hills. With the increase in altitude, the return strike frequency of ground lightning in Changsha area decreases, and the average current intensity of ground lightning exhibits an increasing trend. The current intensity is mainly concentrated within the range of 25~65 kA, of which 77.84% occur in the plain. We used the lightning data in 2019 to test the model and found that the calculated value of annual return strike frequency per unit area is smaller than the observed value, with an average error of 9.20%. The average current intensity model has overestimation compared with observations, with an error of about 4.40%.

Key words: Ground lightning frequency, Current intensity, Terrain factor, Digital elevation model data(DEM)