浙江省地闪特征及致灾危险性分析

基于2007-2018年浙江省ADTD闪电监测资料,分析该区域地闪时空分布特征,进而选用地闪密度和强度作为致灾要素,进行致灾危险性评估.结果表明:落雷日数和正地闪比例的年际变化均呈增长趋势,全年地闪集中发生于6-9月的12:00-20:00.春季正地闪比例高,地闪多发于傍晚和夜间;夏季日地闪落雷面积广、密度极值高,午后...

Analysis of CG Lightning Characteristics and Disaster-Causing Risk in Zhejiang Province

Based on the observation data of the Zhejiang ADTD lightning location system (from 2007 to 2018), the spatial and temporal distribution characteristics of cloud to ground (CG) lightning are analyzed. Considering both CG lightning density and intensity, an analysis of lightning disaster causing risk is made. The results show that the number of thunderstorm days per year and the percentage of positive CG lightning each year both have a rising tendency during the 12 years. The CG flashes mainly occur from 12:00 to 20:00, June to September. In spring, the proportion of positive CG lightning is much higher, while the most of flashes occur in the evening and at night. In summer, there are many abnormally high values of daily lightning density and lightning area, while the peak hour of daily lightning is mainly in the afternoon. The spatial distribution of higher CG lightning density area varies from west to east with season changes. It is also found that the average CG lightning density over the years is higher in the central Zhejiang than in north and south parts. The amplitude of CG lightning current is mainly distributed from 15 to 45 kA. The average value of CG lightning intensity is the highest in Zhoushan (44.49 kA), while the lowest in Taizhou (32.69 kA). The spatial distribution characteristics of lightning intensity and density are different. It suggests that the very high lightning disaster causing risk level locates in the coastal area of the eastern Zhejiang, Hangzhou Shaoxing border, northwestern Wenzhou, central Zhejiang and western Zhejiang. The spatial distribution characteristics of disaster causing risk level are consistent with the number of historical lightning disasters as well as the total number of casualties.