东南沿海前汛期与后汛期降水的比较分析

本文通过对东南沿海前汛期降水与后汛期降水的多年气候变化及500hPa环流场和北太平洋海温场对比分析发现:前汛期降水与后汛期降水在年代际变化上差异明显。前汛期降水逐年变化幅度小,大旱、大涝年少;后汛期降水逐年变化幅度大,大旱、大涝年多。前汛期降水与后汛期降水的大旱、大涝年环流形势场和海温场均存在明显差异。在与北半球500hPa高度场和北太平洋海温场的相关分布上,表现出基本相反的分布类型。计算分析还发现,前期8～9月和冬季1～2月北半球副高,尤其是太平洋副高与前汛期降水相关尚好。前期1月赤道洋流区中部海域的海温,对前汛期降水均有较好的预测指示意义。前期2月北大西洋涛动和黑潮区以东至太平洋中部海域的海温对后汛期降水具有较好的预测指示意义。

Comparison researches on the rainfall of the former and latter flood season in the southeast coastal area of China

Through the comparison analyses of the climatic variation of the rainfall of the former and latter flood season in the southeast coastal area of China,the 500hPa circulation fields,and sea surface temperature(SST) in the north Pacific Ocean,it is found that there is evident difference of decadal variation between the rainfall of the former flood season and that of the latter flood season.The yearly variation range of rainfall in the former rain season is small with few years of drought and flood while the yearly variation range of rainfall in the latter rain season is large with many years of drought and flood.The circulation fields and SST for drought and flood in the former and latter flood season have obvious differences.There is basically negative relation between the 500hPa high fields in the northern hemisphere and the SST in the north Pacific.By calculation,it is also found that the subtropical high of the north hemisphere,especially the Pacific subtropical high,in the former August to September and January to February,and the sea temperature of the middle area in the equatorial oceanic currents have good ability to forecast the rainfall in the former rain season respectively.The north Atlantic oscillation in the former February and the temperature of the sea from the east of black current area to the middle area of the Pacific have good sense to the rainfall forecast in the latter rain season.