Based on statistical analysis of thunderstorm days data recorded by 13 ground weather observation posts of Jiangsu Province from 1961 to 2008, the results show that average annual thunderstorm days decline with years, monthly variation of thunderstorm days presents a single peak, and the thunderstorms are the most frequent in July.The differences in regional distribution of average annual thunderstorm days are obvious, more in the middle while fewer in the north and south.Variation of average annual thunderstorm days also had their own characteristics.Spatial distribution of seasonal thunderstorm days changes with time.It is shown in the principal component analysis that the annual thunderstorm days of 13 cities changed at the same time, but those cities in the north of Huaihe River tended to the opposite phase.The monthly probability of occurrence of thunderstorm days changes in the same manner as the average monthly thunderstorm days, the highest probability of occurrence of thunderstorm days appeared in July.However, the probability did not seem to be exactly the same among all the cities, the probability of July is only a little higher than that of August in Suzhou and Wuxi, while the probability of cities along and north of the Yangtze River is more concentrated in July.The results of this paper can provide a basis for lightning protection and early warning.%利用江苏省13个城市1961-2008年共48 a的雷暴日资料,经过统计分析发现江苏城市年均雷暴日呈逐年下降趋势,雷暴日月变化呈单峰型,7月雷暴日最多,城市年均雷暴日空间分布差异明显,总体呈中部多,两端少分布,各城市历年雷暴日的变化也各有特点,江苏城市四季雷暴的空间分布随季节变化显著.同时应用主成份方法分析得出全省城市年雷暴日异常具有同步性,但江淮北部一淮北地区和江淮南部一苏南地区的城市年雷暴日异常呈反位相.各城市历年每月雷暴日出现概率变化特征与月均雷暴日变化一致,全省各城市在7月出现雷暴日的概率最高,但具体到全省每一个市雷暴日出现概率也有差异,苏州、无锡7月出现雷暴日概率只是略高于8月,而沿江及以北城市雷暴日主要集中分布在7月.
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