河南省46年雷暴的时空变化特征分析

Temporal and Spatial Analysis of Thunderstorms in 46 years in Henan Province

利用自然正交函数(EOF)分解、趋势倾向率分析等方法,对河南省46年雷暴的时空变化特征进行了分析。结果表明,河南省雷暴的空间分布由西北向东南逐步减低,东南地区的雷暴频率较高;雷暴强度等值地区总体呈水平分布。雷暴活动20世纪60年代相对较高,直至80年代后期呈逐渐减少趋势,而近年来雷暴天气呈逐渐上涨趋势,雷暴活动开始频繁;每年的3～8月,雷电在各区域发生概率迅速递增,9月以后又呈递减趋势;一天中16:00～20:00为雷暴发生的高峰时段。河南省雷暴分布变化具有较好的一致性,即雷暴频率同时增加或同时减少;雷暴的年际变化呈一个不太明显的下降趋势。

By empirical orthogonal function（EOF）decomposition and trend analysis methods,the temporal and spatial variation characteristics of thunderstorms in recent 46 years in Henan Province were analyzed.The result showed that the thunderstorms in Henan Province decreased gradually from the northwest region to the southeast region and the frequency of thunderstorms in the southeast area was relatively high.The thunderstorm intensity area was in its horizontal distribution.Thunderstorms acted relative actively in 1960s and tended to dwindle by the end of 1980s.While in recent years,the thunderstorms tended to increase and started acting frequently.Since March to August in every year,thunderstorms multiplied in each region and decreased after September.The period between 16：00 to 20：00 was the high peak hours of thunderstorms every year.Thunderstorms distribution in Henan Province had pretty good consistence,increasing and decreasing at the same time.The annual variation of thunderstorms showed an unobvious decreasing tendency.