【摘要】 利用雷电定位和雷达观测资料对甘肃平凉地区正地闪特性进行了分析。结果表明:正、负地闪回击的上升时间分布范围基本一致,大约在3～20μs之间,其平均值负地闪为8.33μs,正地闪为10.7μs。负地闪回击后的过零时间分布范围较广,在10～130μs之间,其平均值为51μs;正地闪回击后的过零时间分布范围比负地闪要小得多,在10～50μs之间,其平均值为19.67μs。负地闪的反冲深度dp为32%,正地闪为55%。在正负地闪的日变化中,负地闪有两个峰值分别出现在01:00和13:00(北京时,下同),而正地闪在下午18:00出现一个极大值,正负地闪数的分布呈反相关。降雹时间的峰值与正地闪峰值时间有比较好的一致性,正地闪的发生与云中固态水成物粒子的沉降有关。更多还原

【Abstract】 The characteristics of positive cloud\|to\|ground(CG) in Pingliang area of Gansu province were analyzed by use of data of lightning location system and radar. The results indicated that the rise times of lightning return stroke were between 3～20 μs with 10.7 μs mean for positive CG and 8.33 μs for negative CG. The durations of return stroke were between 10～130 μs with 51 μs mean value for negative CG. While the durations of return stroke were between 10 μs～50 μs with 19.67 μs mean value for positive CG. The depth of the dip after the zero crossing was 32% for negative, and 55% for positive CG. The two peak values appeared in daily variation at 01:00 and 13:00 respectively for negative and only one peak value at 18:00 for positive CG lightning. The distribution was reverse correlation between positive and negative CG lightning. The time of hail was correspondingto that of the peak value of positive CG lightning. The occurrence of positive CG lightning was relation with the updraft and downdraft of solid hydrometeors in thunderstorm.更多还原