华东地区降水周期特征及其影响因素分析

Analysis of Precipitation Cycle Characteristics and Its Influencing Factors in East China

根据华东地区32个站点1951-2010年逐月降水量资料,在运用多窗口谱和小波分析方法对降水周期特征进行分析的基础上,利用太阳黑子、南方涛动等相关环流指数与降水序列进行交叉小波分析,探讨影响华东降水周期变化的主要因素。结果表明:华东地区的降水周期在年际和年代际尺度上都有所体现,其中以年代际尺度上的11.6～12.3a周期最为显著,其次为年际尺度上6.0a和4.0a的周期,且不同的周期信号对降水的影响存在阶段性。对华东地区降水周期特征影响较大的因子中,以太阳黑子的影响最为显著,主要体现在准12a周期活动上,其次南方涛动指数、西太平洋副高强度指数和南海副高强度指数对华东降水的影响也较为明显,在准12a和2～8a周期上都有所体现。

According to the monthly precipitation data from 1951 to 2010 of 32 sites in east China,and based on the study of the precipitation cycle characteristics in east China with Multi-taper Method（MTM） and wavelet analysis method,sunspots,related circulation indices such as Southern Oscillation Index,and precipitation series were used for cross-wavelet analysis to discuss the main factors influencing the precipitation cycle characteristics of east China.The results showed that the precipitation in east China had prominent cycles both on interannual and interdecadal scales,among which 11.6～12.3 years cycle（interdecadal scale） was the most significant,following by 6.0 years cycle and 4.0 years cycle（interannual scale）,and different cycles＇ influences on the precipitation were related to different periods.Among all the factors which had significant influences on the precipitation cycles of east China,sunspot activity had the most prominent impact,which was mainly reflected in the precipitation＇s 12 years cycle;the Southern Oscillation Index,the Subtropical High-Intensity Index of West Pacific and the Subtropical High-Intensity Index of South China Sea also have evident influences on the precipitation of east China,which were reflected in the precipitation＇s 12 years cycle and 2～8 years cycle.