Abstract:

The influence of terrain on lightning current parameters cannot be ignored as a basis for lightning theory study and engineering protection application. Thus, in this study, the impacts of altitude, slope, aspect, and soil conductivity on the characteristics of cloud-to-ground lightning distribution in Qinghai Province, China, were quantitatively analyzed using cloud-to-ground lightning data from 2014 to 2018, digital terrain altitude data, and the HWSD data set. As per the data, it was determined that (1) cloud-to-ground lightning mostly concentrated at the altitude of 3150-4850 m and a slope of 0-35°. The number of slope to the northeast had the greatest cloud-to-ground lightning, whereas the one to the southeast had the least. The electrical conductivity corresponding to cloud-to-ground lightning is primarily concentrated at a distance of 100 Ω·m. (2) For a given unit area, the cloud-to-ground lightning frequency increased first and then decreased with altitude. The number of cloud-to-ground lightning strikes increases slowly as the slope increases. In addition, the average cloud-to-ground lightning intensity decreases first and then increases as altitude increases. It showed a trend of gradual increase as the slope increased and an increasing trend as the conductivity increased. (3) A correlation analysis was performed between the cloud-to-ground lightning data and the mean value of the geographical parameters in a 1 km×1 km grid covering the active areas of 92°27′00′′-97°44′24′′E and 31°40′48′′-34°16′48′′N. The cloud-to-ground lightning density in the selected areas was positively correlated with altitude and negatively correlated with the slope. A negative correlation was noted between cloud-to-ground lightning intensity and mean altitude, but a positive correlation with slope.

Key words: lightning activity, altitude, slope, slope direction, soil conductivity, Qinghai Plateau