江淮梅雨特征及其与北太平洋海温的SVD分析

利用江淮地区1954～2001年48年梅雨量资料,采用谐波分析、EOF、合成分析和SVD分解等方法讨论了江淮梅雨的时空变化特征以及与北太平洋海温的关系.结果表明:江淮梅雨量时空分布不均,存在显著的年际和年代际变化特征.影响江淮梅雨的海温关键区是北太平洋西风飘流区,关键影响时段是当年的1～3月;当年1～3月北太平洋西风飘流区海温异常偏高,同年江淮大部地区梅雨量异常偏多,反之亦然.SVD分解结果与合成分析的结果相吻合,通过0.05的Monte-Carlo显著性检验.

CHARACTERISTICS OF MEIYU PRECIPITATION AND SVD ANALYSIS OF PRECIPITATION OVER THE CHANGJIANG-HUAIHE RIVER VALLEY AND THE SEA SURFACE TEMPERATURE IN THE NORTHERN PACIFIC OCEAN

Based on the precipitation of Meiyu at 37 stations in the Changjiang-Huaihe river valley from 1954 to 2001,the temporal-spatial characteristics of Meiyu precipitation and the relationship of the sea surface temperature in the northern Pacific Ocean are investigated in terms of harmonic analysis,empirical orthogonal function (EOF),composite analysis,singular value decomposition (SVD) and others. Results show that the temporal evolution and spatial distribution of Meiyu precipitation are not homogeneous in the Changjiang-Huaihe region. There are prominent inter-annual and inter-decadal variabilities of Meiyu precipitation. The key region between the precipitation anomalies of Meiyu precipitation and the monthly sea surface temperature anomalies (SSTA) lies in the west wind drift of North Pacific Ocean,which influences the precipitation anomaly of Meiyu precipitation and the key period of time is from January to March in the same year. Meiyu precipitation is increasing (decreasing) in the corresponding period when SST of north Pacific Ocean in the west wind drift from January to March is warmer (colder) than average. Results of SVD are consistent with those of composite analysis which passed the significance test of Monte-Carlo at 0.05.