江苏省雷暴非均一性特征分析

Non-uniformity of Thunderstorms in Jiangsu

对江苏省1961～2008年共48年逐日雷暴日资料进行统计和分析。结果表明,江苏年均雷暴气候倾向率为负,呈逐年下降趋势;年雷暴日数分布区间主要集中在20～40d,约占总雷暴日数分布区间的77%;江苏雷暴呈单峰型月变化特性,夏季雷暴最多,占全年的70.28%,冬季雷暴最少,只占1.05%,各月雷暴分布的地区存在明显差异;江苏年均雷暴日和标准差地域分布呈非均一性分布,总体呈苏中多、苏南和苏北少的地域分布;四季雷暴日的空间分布也呈现非均一性特点。全省各地区年雷暴异常具有同步性,但苏北和苏中、苏南年均雷暴异常呈反位相。全省各市历年逐日雷暴发生概率:7月中下旬最高,但具体到全省每一个市,每一天,发生雷暴概率非均一性特点也十分显著。

Statistics and analysis on the data of thunderstorm days recorded by 13 ground weather observation posts of Jiangsu Province from 1961 to 2008 revealed that average annual thunderstorm days declined with years.The thunderstorm days were mainly 20-40 d accounting for 77% of total annual thunderstorm days.Monthly variation of thunderstorm days presented a single peak with 70.28% of the thunderstorms in summer and only 1.05% in winter.Distribution of monthly thunderstorms had an obviously regional difference.The spatial distribution standard deviation was consistent with average annual thunderstorm days,both of which were non-uniform（more in the central part of Jiangsu but less in the northern and southern part of Jiangsu）.Seasonal thunderstorms also presented non-uniformity.The annual thunderstorm days of the 13 cities in Jiangsu changed at the same time,but those in the northern part of Jiangsu went to the opposite side of the central and southern part of Jiangsu.The highest probability of occurrence of thunderstorms of the whole province was in the middle and late July.However,the non-uniformity of the probability of a specific city or day was also significant.