近十年江汉平原雷电活动特征分析与灾害防御

Analysis of Lightning Activity Characteristics and Disaster Prevention in Jianghan Plain in Nearly A Decade

为研究江汉平原云地闪电活动特征,依据湖北省ADTD(Adranced Direction Finding on Time Difference)闪电监测系统2007-2016年10年的监测资料,采用数理统计方法 ,对该区域10年间云地闪电频次的年、月、日和季节变化以及雷电流幅值分布特征进行统计分析。结果表明,2007-2016年,云地闪电频次有逐年降低的趋势,但正闪比例逐年升高,频次未降。年平均负闪电频次占总闪电频次的94.50%,正闪占5.50%。夏季闪电频次最多,但正闪占比最小,仅有4.70%;冬季闪电最少,而正闪占比最大,是夏季正闪电占比的2.5倍以上。总闪电频次的月变化呈现单峰型特征,峰值出现在7月,12月闪电频次最少。通常状况下,正闪平均强度均大于总闪平均强度和负闪平均强度,正闪平均强度在25~70 k A之间;总闪和负闪的平均强度在30~45 k A之间。总闪电频次日变化特征明显,呈单峰单谷型,其中,云地闪电频次最多和最少的时段分别出现在15:00~16:00和10:00~11:00,农民外出劳作应尽量避免雷电高发时段。

In order to study the activity characteristics of cloud to ground lightning in Jianghan plain,according to the monitoring data of ADTD（Adranced Direction Finding on Time Difference） lightning monitoring system in Hubei province during the ten years of 2007-2016,using the method of mathematical statistics, the region ten years of cloud to ground lightning frequency of the year,month,day and seasonal changes and the amplitude of lightning current distribution characteristics were analyzed. The results showed that the 2007-2016,cloud point frequency was gradually decreased year by year, but the proportion and frequency of positive lightning increased year by year,did not fall. The annual average negative lightning frequency accounted for 94.50% of total lightning frequency,and 5.50% of positive lightning frequency. The lightning frequency was the highest in summer,but the percentage of positive lightning was the smallest, only 4.70%. Lightning was the least in winter,while the percentage of positive lightning was the largest,which was more than 2.5 times of the percentage of positive lightning in summer. The monthly change of total lightning frequency showed a single peak characteristic,the peak appeared in July,and the lightning frequency was the least in December. Under normal conditions,the average intensity of positive lightning was greater than the average intensity of the total lightning and the average intensity of negative lightning. The average intensity of positive lightning was between 25~70 k A,and the average intensity of total and negative flashes was between30 ~45 k A. The characteristics of diurnal variation of total lightning frequency was a single peak and single valley type,the cloud to ground lightning frequency maximum and minimum time respectively appeared between at 15 ：00~16：00 and 10：00~11：00, farmers out labor should avoid high incidence of lightning.