上海地区雷暴时空分布特征分析

Analysis on Features of Spatio-temporal Distribution of Thunderstorm in Shanghai

利用1971～2008年上海地区11个测站的逐日雷暴观测资料,利用统计分析软件SAS和Mann-Kendall突变检验和小波分析等方法,对上海地区雷暴的气候变化特征等进行了分析。结果表明,上海近38年来年均雷暴日为26.1d,年际变化幅度较大;年雷暴日呈显著减少趋势,倾向率平均为-0.4185d/10a,在2000年左右发生了减少性突变;各月都有可能发生雷暴,但主要发生在3～9月,占全年雷暴日数的96.4%,其中夏季雷暴日(6～8月)约占全年64.9%;从小波分析的结果看,上海地区雷暴具有3年、5年的短周期和12年、20年的长周期震荡变化。

Based on 11 daily weather observation station datum in Shanghai from 1971 to 2008,a careful research and analysis on the features of thunderstorm spatio-temporal distribution and thunderstorm movement in Shanghai was carried out by using the statistical software of SAS,the method of Mann-Kendall test and wavelets.The results showed that the mean annual numbers of thunderstorm days are 26.1,and inter-annual thunderstorm variability is obvious,the annual number of thunderstorm days has a decreasing trend,its value of decreasing days is about-0.418 5 d/10a.Mann-Kendall test showed that there was an abrupt change in 2000.The seasonal variation of thunderstorm in Shanghai is obvious.the period from March to September was the season when thunderstorm occurred the most frequently,about 64.9% of thunderstorms in a year occurred in summer.The thunderstorm appears three or four centers and the centers do not move almost.The results from wavelets analysis showed that the variation period of annual number of thunderstorm days is about the short periods of 3 years,5 years and the long periods of 12 years and 20 years.