利用安徽省78个气象台站1971~2010年逐日雷暴大风资料,统计出历年各站雷暴大风日数并分析其时空分布特征,通过M K突变检验、小波分析、EOF分析等方法对安徽省近40 a雷暴大风的时空变化特征进行分析。结果表明:安徽省雷暴大风日数存在显著的减少趋势;夏季6~8月是雷暴大风最为集中的时段,约占全年的69%;雷暴大风的日变化上主要呈现单峰结构,峰值在15~16时。空间分布特征和纬度没有太大的关系,主要是和对流天气系统的影响区域及地形因素有关。安徽省雷暴大风日在1987年存在一次显著突变,小波分析表明存在着准10 a和6~8 a周期左右的显著振荡,10 a的时间尺度上,雷暴大风日数经历了由多到少4个循环交替,多雷暴大风时期主要在1995年左右及2003~2005年左右,2010年之后雷暴大风日数仍将处于减少状态。对于10 a准周期,1995年以前10 a振荡较小,而1995年后振荡剧烈;雷暴大风日数EOF展开前4个模态累积方差贡献达61%,第一模态能大部分反映安徽省雷暴大风日年分布的主要特征;各模态的时间系数表现为明显的年代变化
This paper counted up the station thunderstorm gust days over the years and analyzed the temporal and spatial distribution characteristics by using 78 meteorological stations daily thunderstorm gust data in Anhui Province from 1971 to 2010.It also analyzed the temporal and spatial variation of thunderstorm gust in recent 40 years in Anhui Province by using Mann Kendall method,wavelet analysis method,EOF decomposition method and etc.The results show as follows.There was a significant decreasing trend of thunderstorm gust days sum in Anhui Province.The most concentrated period of time for thunderstorm gust was in the summer from June to August,accounting for about 69% of the year.The diurnal variation of thunderstorm gust mainly showed single peak structure,peaking in 15〖DK〗∶00 to 16〖DK〗∶00 BT.The spatial distribution characteristics had no obvious relationship with latitude,mainly had relationship with the influence of convective weather system and factors of regional and terrain.Thunderstorm days had a significant mutation at 1987 in Anhui Province.Wavelet analysis showed that there were 10 years and 6-8 years significant oscillation cycle.In the time scale of 10 years,thunderstorm gust days experienced 4 alternating cycles from more to less,multiple thunderstorm gust periods were around 1995 and from 2003 to 2005,and the thunderstorm gust days would remain in the reduced state after 2010.For 10 years the quasi periodic,oscillation of 10 years was small before 1995,but intense oscillation occurred after 1995.The contribution of the first four modal cumulative variance of EOF decomposition of thunderstorm gust days was up to 61%.The first mode could most reflected the main characteristics of thunderstorm days annual distribution in Anhui Province.The time coefficients of each mode had obvious interdecadal variation