湖泊与陆地雷电参数分布特征及其对比分析

根据湖北省雷电定位系统（Lightning Location System，LLS）2007年1月1日至2016年12月31日监测资料，采用数理统计方法，对湖泊和陆地区域的地闪频次、极性、地闪密度、雷电流幅值和波头陡度等雷电参数分布特征进行了对比研究。结果表明：湖泊与陆地的雷电参数时间变化趋势基本一致。近10 a闪电频次呈明显减少趋势，正地闪比例呈上升趋势；陆地比湖泊区域的闪电频次多，春夏季湖泊和陆地闪电频次差异明显，其中，夏季陆地闪电频次比湖泊多21.1%；湖泊和陆地闪电频次日变化大致呈单峰型，13-18时陆地闪电频次比湖泊多39.7%。湖泊地闪密度比陆地小，湖泊和陆地平均地闪密度分别为2.96次·（km^-2·a^-1）和3.47次·（km^-2·a^-1）。湖泊的平均雷电流幅值较陆地大；湖泊和陆地的平均雷电流波头陡度变化不大，相差一般在1 kA·（μs）^-1以下。

Distribution characteristics and comparative analysis of lightning parameters between lakes and lands

The distribution characteristics of cloud-to-ground (CG) lightning frequency,polarity,lightning density,lightning current amplitude,and gradient of wavefront of lakes and lands were compared using mathematical statistics method based on the data monitored by Lightning Location System (LLS) in Hubei province from January 1,2007 to December 31,2016.The results show that the temporal variation trends of lightning parameters for lakes and lands are similar.Lightning frequency decreased insignificantly in the last 10 years,and the percentage of positive CG lightning showed an increasing tendency.There are more lightning frequencies on lands than that over the lakes,and lightning frequency of lakes and lands are significantly different in spring and summer,in which lightning frequency of lands in summer is 21.1% higher than that of lakes.The diurnal variation of lightning frequency for lakes and lands appears to be unimodal,and lightning frequency of lands is 39.7%,which is higher than that of lakes from 13 p.m.to 18 p.m.The average CG lightning density of lakes is smaller than that of lands,and the average CG lightning densities of lakes and lands are 2.96/(km²·a) and 3.47/(km²·a),respectively.The average lightning current amplitude of lakes is larger than that of lands.The average wavefront steepnesses of lightning current for lakes and lands have little differences,and the difference between them is generally less than 1 kA/μs.