浙江雷电活动时空分布规律及灾害风险区域划分研究OA

Influenced by the monsoon climate and complex terrain,Zhejiang Province experiences frequent light-ning activity with distinct spatiotemporal characteristics.To support the enhancement of lightning monitoring,early warning,and protection capabilities in Zhejiang,lightning detection data from 2010 to 2024 were selected for analy-sis.First,the annual and seasonal spatiotemporal distributions of mean ground flash density(GFD)were statisti-cally examined.The results show that over the past 15 years,lightning activity in Zhejiang increased from southwest to northeast,with pronounced seasonal variability.Lightning was most concentrated in summer,and the diurnal variation of average lightning density showed a single-peaked distribution,with peak lightning occurrence concen-trated between 15:00 and 17:00.Second,a polarity-based statistical analysis of lightning frequency and intensity revealed that negative flashes accounted for more than 57%of all events,and the monthly mean lightning peak cur-rent primarily ranged from 28.0 to 37.7 kA.Finally,lightning risk zoning was conducted based on regional lightning withstand levels.Except for coastal islands,most areas reached grade C1 or above.For lightning protection of trans-mission lines,shielding failure is the main concern for 500 kV lines,whereas both shielding failure and back-flashover must be considered for 220 kV lines.For 220 kV and above lines across Zhejiang,the risks of shielding failure and back-flashover are predominantly at grade III,with grade IV risk areas being relatively limited and mainly located in Wenzhou,Taizhou,Ningbo,and parts of Lishui.The results provide technical support for re-gional lightning hazard prevention in Zhejiang Province.