中部5省南北闪电参数分布特征

在利用我国中部5省(湖南、湖北、江西、安徽、河南)经济协作区52个闪电监测站2007—2010年闪电定位资料和1961—2010年雷暴日资料,分析协作区内闪电参数的分布特征的过程中,发现中部5省闪电参数在30.8°N纬度带两侧呈现不同的变化规律.36.4~30.8°N,正闪强度整体呈下降趋势,正闪陡度变化较小,平均值为16.48 kA·μs-1,负闪强度和陡度在32°N附近形成极大值后,在30.8°N附近迅速下降;一天中闪电频数最大值与最小值出现时间比较分散;初雷日约为4月5日、终雷日约为9月17日.30.8~24.4°N,正、负闪电强度绝对值呈上升趋势,正闪强度上升较快,从52.11 kA上升至77.88 kA,负闪强度绝对值上升较平缓,正闪陡度变化较小,平均值约为14.24 kA·μs-1,负闪陡度呈下降趋势,由12.07 kA·μs-1下降到8.90kA·μs-1;闪电频数最大值出现时间集中在15—16时,闪电频数最小值出现时间集中在8—10时;初雷日约为2月18日,终雷日约为10月17日.

Distribution characteristics of cloud-ground lightning in five provinces of central China

Data of lightning location （2007-2010） and thunderstorm day （1961-2010） from 52 ADTD lightning detection stations are used to analyze characteristics of lightning parameters for five provinces （ Hunan,Hubei,An-hui,Jiangxi,Henan） in central China. Results show that lightning parameters present different variation patterns in latitudes on the northern and southern side of 30？8＆#177;0？2＆#176;N.In latitude from 36？4＆#176;N to 30？8＆#176;N,the positive light-ning intensity descends,with small positive lightning gradient change and average value of 16？48 kA＆#183;μs-1 . While the negative lightning intensity and gradient reach maximum at 32＆#176; N and then fall rapidly at 30？8＆#176; N. The occurrence time of maximum and minimum lightning frequency shows a decentralized appearance in a day,and the thunderstorm day starts from approximately April 5 and ends at approximately September 17 in a year.While in lati-tude from 30？8＆#176;N to 24？4＆#176;N,both the positive and negative lightning intensity increase,but the positive one increa-ses rapidly from 52？11 kA to 77？88kA and the negative one increases slowly. The positive lightning gradient has small change with average value of 14？24 kA＆#183;μs-1 ,and the negative lightning gradient decreases from 12？07 kA＆#183;μs-1 to 8？90 kA＆#183;μs-1.Most lightning occurs on 15：00-16：00,and the least lightning occurs on 8：00-10：00 in a day,the thunderstorm day starts from about February 18 and ends at about October 17 in a year.