福建省地闪时空分布特征分析

Analysis of spatiotemporal distribution characteristics of cloud-to-ground lightning in Fujian Province

为了给防雷减灾工作提供必要的参考依据，以福建省2007—2011年闪电监测资料及ASTERGDEM高程数据为基础，运用数理统计方法并结合SURFER及ARCGIS软件，详细分析了福建省地闪的时空分布特征。研究表明：正／负地闪活动均在8月最为强烈，负地闪主要集中在5～9月，正地闪在12～3月发生概率较高；一天中，负地闪在13：00—20：00发生最为频繁，正地闪迟于负地闪，并在凌晨存在一小高峰；正地闪强度中位数呈现较为显著的月变化，负地闪则不明显；一天中各时段都以0—37．5kA的地闪为主，但任何时段都可能发生强地闪；地闪密度分布受地形影响较大，受流域分布影响小，地闪密集地带多处于丘陵与平原交接地带；地闪强度中位数在沿海海岛较大；正／负地闪密度及正地闪强度中位数与海拔存在着非线性关系，负地闪强度中位数随海拔变化不明显。

Based on the monitoring data of lightning location system in Fujian Province from 2007 to 2011 and the ASTER GDEM altitude data, the spatiotemporal distribution characteristics of cloud- to- ground （CG） lightning were analyzed using the mathematical statistics methods and the SURFER and ARCGIS software, to provide the necessary reference to the work of lightning protection and disaster reduction. Results show that, the positive CG lightning and negative CG lightning appear most frequently in August. The frequency of negative CG lightning is mainly concentrated in a period from May to September, and the occurrence probability of positive CG lightning from December to next march is high; Negative CG lightning activities occur frequently in a period from 13：00 - 20：00 in a day; positive CG lightnings occur later than the negative CG lightings and there is a small peak early in the morning. The median peak current of positive CG lightnings varies significantly by month, while negative CG lightnings do not. Lightning intensity is mainly about 0 - 37.5kA , but the high peak current lightnings may occur at any time of a day. The distribution of CG lightning density is greatly influenced by topography and less influenced by river basin. Hills and plain transition zone is a CG lighting prone area. The median peak current of CG lightnings is greater in coastal islands than in planes. The positive/negative CG lightning density and the median peak current of positive CG lightnings show a nonlinear relationship with altitudes, but the median peakcurrent of negative CG lightnings doesnt change obviously with ahitude.