近50年湖南省雷暴气候特征分析

Climatic characteristics of thunderstorm over past 50 years in Hunan province

根据湖南省74个地面气象站1961—2010年的雷暴日资料,利用数理统计、小波分析及Mann-Kendall检验等方法,对近50年雷暴气候特征进行分析.结果表明:1)湖南省雷暴日数空间分布特征为南部多、北部少,最大值出现在南部山地(65.38 d/a),最小值出现在北部平原(21.92 d/a),月平均雷暴日呈单峰值分布,3—9月为雷暴高发期;2)湖南省年平均雷暴日数存在8、16、24和30 a的周期变化规律,其中8 a周期振荡最显著;3)多雷期和少雷期的差异主要表现在副热带高压西伸脊点的位置以及青藏高原短波槽的位置和强弱上.

Using the data of thunderstorm days recorded by 74 ground meteorological observatories in Hunan province from 1961 to 2010,the climatic characteristics of thunderstorms during the past 50 years were analyzed by means of mathematical statistics,wavelet analysis and Mann-Kendall test.The results show that there is a deceasing trend of thunderstorm days from the north to the south,with the highest number of thunderstorm days in the mountainous region of the south for 65. 38 d/a,and the lowest number of thunderstorm days in the plain of the north for21. 92 d/a.The distribution of average monthly thunderstorm days are observed to be a single peak curve,with the peak period appear in March to September. The oscillation periods of 8 years,16 years,24 years and 30 years are found in the number of average annual thunderstorm days in Hunan,with most remarkable period being 8 years.The climatic difference between the periods with more or less thunderstorm days appears as the position of westward move of the subtropical high over the Western Pacific,as well as the position and strength of short-wave trough of Tibetan Plateau.