内蒙古地形因素对雷电灾害的影响及其权重分析

为了揭示内蒙古地形对雷电灾害的影响规律,基于内蒙古1998—2018年雷电灾害资料和数字高程数据,运用数理统计和熵值法分析了内蒙古地区地形因素对雷电灾害的影响及其权重.结果 表明,内蒙古近21年来雷灾点主要分布在高程为200～2000 m的范围内,高程在2000 m以上基本没有雷灾发生;雷灾点个数随坡度、地形起伏度的增加呈现指数降低趋势,雷灾点主要分布在坡度小于10°的地区,且多分布在0～75 m的地形起伏度区间内;从坡向上来看,南坡的雷灾点个数最多(占45.53％),北坡的雷灾点个数最少;在地形因子的不同分级中0～500 m的高程、15°～35°的坡度、0～20 m的地形起伏度和西南坡及平地区域发生雷灾的概率较大.运用熵值法分析高程、地形起伏度、坡度和坡向不同地形因素造成雷电灾害权重来看,高程和坡向因素贡献程度较大.该研究结果对于雷电灾害的风险区划及防御规划有一定指导意义.

Influence of topographical factors on lightning disasters and weight analysis in Inner Mongolia

Based on the lightning disaster data from 2009 to 2018 and digital elevation data of Inner Mongolia, the influence and weight of terrain factors on lightning disaster were analyzed by mathematical statistics and entropy method. The results show that in the past 21 years, the lightning disaster spots in Inner Mongolia were mainly distributed in the range of elevation between 200 m and 2000m, and there were basically no lightning disasters above 2000m,the number of lightning disaster points decreases exponentially with the increase of slope and topographic relief. The lightning disaster points were mainly distributed in the areas with slope less than 10° and were mostly distributed in the topographic relief interval of 0-75m, From the perspective of slope upward, the number of lightning disaster points on the south slope was the highest (accounting for 45.53%), and the number of lightning disaster points on the north slope was the lowest. The elevation of 0-500m, the slope of 15 ° -35 °, the topographic relief of 0-20m and on the southwest slope and flat land the probability of lightning disaster are higher in different classifications of terrain factors. The entropy method was used to analyze the weights of lightning disasters caused by different topographic factors such as elevation, topographic relief, slope and slope direction. The results of this study have some guiding significance for lightning hazard risk zoning and defense planning.