2007～2008年大连地区闪电时空分布特征分析

Analysis on the Spatio-temporal Distribution Features of Lightning in Dalian Area from 2007 to 2008

采用大连地区不同地理位置的4个雷击探测仪组成的闪电监测定位系统获取的2007-2008年云地闪电资料,从闪电的极性分布、日变化、强度、闪电密度等方面,研究了大连周边地区云地闪电时空分布特点。结果表明,云地闪中负闪电占闪电总数的93.9%,平均闪电强度为27.99 kA;正闪电占闪电总数的6.1%,平均闪电强度为35.56 kA;闪电频次的日变化呈明显的双峰双谷结构,17：00-18：00和04：00-05：00为2个峰值,2个谷值分别出现在09：00-10：00和00：00-01：00;5-9月闪电次数占全年闪电总数的91.5%,其中6-8月闪电次数最多;正、负闪电的强度主要集中在15-35 kA,80%以上闪电强度小于40 kA,100 kA以下的闪电次数约占闪电总数的99.3%;大连周边地区闪电空间分布呈明显的地域性差异,辽东湾和大连东部沿海地区是对流发生的主要发生地,远离海区的内地区域闪电发生的频率要低的多,沿海地区是大连周边地区雷电灾害防御工作重点。

Based on the cloud-to-ground lightning data from 2007 to 2008 obtained by the lightning detection and location system composed of 4 lightning detectors from different sites of Dalian area,the spatio-temporal distribution features of cloud-to-ground lightning in surrounding area of Dalian were analyzed from several aspects of lightning polarity distribution,daily variation,intensity and density.The results showed that the percentage of negative lightning to total number of lightning was 93.9%,with the average lightning intensity of 27.99 kA;the percentage of positive lightning was 6.1%,with the average intensity of 35.56 kA;daily variation of lightning frequency showed an obvious structure of two peaks and two valleys,two peaks value occured during 17：00-18：00 and 04：00-05：00,two valleys value occured during 09：00-10：00 and 00：00-01：00.The number of lightning appearing from May to Sep.was 91.5% of the total,among which,the lightning occured most frequently in Jun.to Aug.;the intensity of positive and negative lightning was mainly concentrated in 15-35 kA,over 80% lightning intensity was not more than 40 kA.The number of lightning whose intensity being less than 100 kA accounted for 99.3% of the total;the lightning density distribution had obvious regional difference,one high density area of lightning was Liaodong Bay,another was Dalian Bay;the lightning frequency in mainland area was much lower,coastal area was lightning disaster prevention focus in surrounding area of Dalian.