基于1971—2007年呼和浩特地区6个气象站的逐日雷暴观测资料,运用数理统计及小波分析等方法,对呼和浩特地区雷暴的时空分布特征和气候变化规律进行分析。结果表明:呼和浩特地区年平均雷暴日数为36.4d,呈南北多中部少的纬向型特征;37年来雷暴日数在波动中呈减少趋势,平均下降幅度为1.435 d/10a;该地区的雷暴有很强的季节性特点,集中出现在5—9月的5个月中,而夏季(6,7,8)3个月占73.5%;从小波分析的结果看,呼和浩特地区雷暴具有2、3年和4年的短周期及12、20年的长周期震荡变化,其中以长周期震荡为主要特征。
Using the observational thunderstorm data of 9 weather stations in Hohhot from 1971 to 2007 years,the thunderstorm characteristics of Climate change and spatio-temporal distribution were analyzed by means of mathematical statistics and the analysis of wavelets.The results showed that the mean annual numbers of thunderstorm are 36.4 days,the annual-average thunderstorm days were the least in central region of Hohhot area and the most in the north and south region,the annual number of thunderstorm days has a undulate decreasing trend in departed 37 years,its value of decreasing days was about 1.435per decade.The seasonal variation of thunderstorm in Hohhot area was obvious.Throughout the year from May to September period for thunderstorms concentrated.The 73.5% thunderstorm appeared in June,July and August.The results from wavelets analysis showed that the long oscillation variation period of thunderstorm days was 12 years and 20 year,and the short period of thunderstorm days was 2、3 years、4 years,the long periods oscillation were the main characters.