Abstract:The influences of geographic parameters (elevation, slope, aspect, land cover type and soil electric conductivity) on cloudtoground (CG) lightning in Zhejiang Province are quantitatively studied based on the CG lightning data in 2007 and 2016, DEM data (Digital Elevation Model), land cover type data and the HWSDbased China Soil Map (Harmonized World Soil Database). The results show that CG lightning in Zhejiang Province is mainly concentrated in the range of 0 to 600 m above the sea level, and 0°to 30° with respect to the slope. As for the aspect, the highest number of CG lightning is in the southeast, and the lowest is in the west. Besides, the forest area has the largest number of CG lightning, whereas the wetland has the smallest one. The corresponding soil electric conductivity of the CG lightning is mainly focused on 0.1 dS/m. Taking into account the proportion of area, the number of CG lightning per square kilometer increases firstly, following a decrease trend with the rise of elevation, slope, and soil electric conductivity, respectively. The highest frequency of CG lightning is found in the southern and southeastern slope areas, and the lowest is in the western and southwestern slope areas. The urban area covered with buildings has the largest number of CG lightning per square kilometer, while the water body has the smallest one. The average ground flash intensity decreases first and then increases with the increase of elevation; the mean lightning current steepness shows a decreasing trend with increasing elevation; and these two parameters decrease with the increasing slope and rise gradually with the increase of soil electric conductivity. The correlation analysis between average geographic parameters and lightning activity based on the 5 km×5 km grids shows that both lightning current intensity and steepness have a negative correlation with elevation and slope, respectively.
