近33 a珠海市雷暴日数的时间变化特征

基于珠海市近33a雷暴日资料,利用Morlet小波分析、累积距平和M-K突变检验等方法对珠海市雷暴日的演变趋势、周期变化和突变特征等进行全面分析,结果表明:(1)珠海市雷暴日有明显的季节变化特征,表现为夏半年偏多,冬半年偏少;(2)雷暴日的年际变化表现为下降-上升-平缓的演变特征,而且在各个时间尺度上都有明显的周期变化;(3)四季雷暴日的年际变化不同,春季、秋季和冬季均有不同程度下降趋势,而夏季为上升趋势,并通过99%的信度检验;(4)四季雷暴日在不同时间尺度上的周期变化不同,春季周期振荡在4～6a的时间尺度最为剧烈,夏季在6～8a的时间尺度上,秋季从高频到低频都有明显的周期振荡,冬季各个频率上的周期振荡都较为明显,2000年之后周期振荡有转弱的趋势;(5)M-K突变检验表明夏季雷暴日在1994-1995年有突变现象。研究结果有助于了解珠海地区雷暴的变化特征,对科学防御雷暴灾害、科学规划和设计雷电防护等有重要作用。

Characteristics of Time Change of Thunderstorm Days in Zhuhai City in the Near 33 Years

Based on the data of thunderstorm days in Zhuhai City in recent 33 years, the evolution trend, periodic variation and mutation characteristics of thunderstorm days in Zhuhai City were comprehensively analyzed by Morlet wavelet analysis, cumulative anomaly and M-K mutation test. The results show that:(1) thunderstorm days in Zhuhai have obvious seasonal variation characteristics, which are more in summer half year, and less in winter half year. (2) The interannual variation of thunderstorm days is characterized by a decline-rise-gentle evolution, and there are obvious periodic variations on various time scales. (3) Interannual variations of thunderstorm days are different in the four seasons, with different degrees of decline in spring, autumn and winter, while in summer, it shows an upward trend, and the reliability test is 99%. (4) The four seasons have different periodic changes on different time scales. The spring periodic oscillation is the most severe on the time scale of 4-6 years, while in summer the most severe oscillation is on the time scale of 6-8 years. There are obvious periodic oscillations in autumn from high frequency to low frequency. The periodic oscillations at various frequencies in winter are more obvious. After 2000, the periodic oscillations tend to weaken. (5) M-K mutation test shows that there is a sudden change in summer thunderstorm days from 1994 to 1995. The research results will help to understand the changing characteristics of thunderstorms in Zhuhai area, and play an important role in scientific defense against thunderstorms and scientific planning and designing in lightning protection.