江苏苏南地区高速公路闪电时空分布特征研究

利用江苏省闪电监测定位系统探测2007—2013年地闪观测资料和2013年云闪观测资料,研究了苏南地区高速公路沿线地闪和云闪的时空分布特征。研究表明:1)苏南地区高速公路的年、月地闪频次具有西部多于东部的分布特征,其中扬溧高速最多;6—8月是地闪出现的高峰期,且西部地区出现峰值时间(7月)早于东部地区(8月);但日地闪频次的峰值出现时间东部(13～16 h)要略早于西部地区(14～18 h)。2)地闪强度(峰值电流)主要集中在20～50 kA,总体趋势是东部大于西部;高速公路地闪强度高值区主要集中在宁镇丘陵以及太湖、长江沿线附近,其中南京绕城高速、扬溧高速镇江段、宁杭高速南京段、沿江高速无锡段、沪宁高速等都是地闪密度较高路段。3)云闪集中发生在5—9月,西部地区云闪频次波动明显,总体呈双峰型月变化分布特征;东部地区云闪频次相对集中,呈单峰型月变化分布特征;西部地区出现云闪日高频次的时间(13～18 h)要早于东部地区(17～18 h)。

Temporal and spatial distribution patterns of lightning activities along expressways in southern Jiangsu

In the present study,based on the observed cloud-to-ground(CG) lightning location data from the period of 2007 to 2013 and the new observed intracloud(IC) lightning location data for 2013 in Jiangsu Province,the temporal and spatial pattern of CG and IC lightning activities along the expressways in southern Jiangsu were investigated.The following results were observed:(1)There were a greater number of CG lightning activities along the western expressways than the eastern ones.The highest frequency appeared along the Yangzhou-Liyang Expressway,the peak period of CG lightning activities in a given year was from June to August,and the peak time (July) along the western expressways was earlier than in the eastern region(August).However,the peak time (13:00 BST-16:00 BST) in the CG lightning frequency along the eastern expressways was slightly earlier than in the western region(14:00 BST-18:00 BST).(2)The CG lightning current(peak current) was mainly concentrated in the range of 20~50 kA,while the overall lightning current trend in the east was greater than in the west.The regions where CG lightning activities occurred most frequently were Nanjing-Zhenjiang Hills,Taihu Lake and the Yangtze River Valley.Among these,the expressway near Nanjing City,the Zhenjiang part of the Yang-Liyang Expressway,the Nanjing part of the Nanjing-Hangzhou Expressway,the Wuxi part of the Expressway along the Yangtze River,and the Shanghai-Nanjing Expressway were the highest CG lightning density sections.(3)The IC lightning activities in 2013 occurred mainly from May to September.The IC lightning frequencies along the western expressways fluctuated significantly in a distribution type of double peak months.The IC lightning activities along the eastern expressways were relatively concentrated,and exhibited a distribution type of a single peak month.The time of IC lightning along the western expressways(13:00 BST-18:00 BST) was earlier than along the eastern expressways (17:00 BST-18:00 BST).