高原复杂地理参数对雷电活动的影响分析

Influence analysis of geographic parameters on lightning in plateau

雷电活动参数作为反映区域雷电活动特征的重要指标,地形对其影响不容忽视。利用2014—2018年青海省地闪数据、数字地形高程数据以及HWSD土壤数据集,定量分析海拔、坡度、坡向以及土壤电阻率对青海省地闪分布特征的影响。结果表明:(1)青海省地闪主要集中在海拔3150~4850 m、坡度0~35°的地区,其中东北坡向地闪次数最多,东南坡向地闪次数最少,地闪对应的土壤电阻率主要集中于100Ω·m。(2)地闪密度随海拔的升高先增大后减小,随坡度的增大而减小;地闪平均强度随海拔的升高先减小后增大,随坡度的增大而增大。(3)选取92°27′00″~97°44′24″E、31°40′48″~34°16′48″N地闪活跃区域,对其1 km×1 km网格内地闪数据与地理参量平均值进行相关性分析,所选区域内地闪密度与平均海拔呈正相关关系,与平均坡度呈负相关关系;而地闪强度与平均海拔呈负相关关系,与平均坡度呈正相关关系。

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-toground 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 100Ω·m.(2)For a given unit area,the cloudto-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-toground 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.