北太平洋海温的主成分分析

PRINCIPAL COMPONENT ANALYSIS OF THE SEA SURFACE TEMPERATUES OF THE NORTH PACIFIC

对北太平洋(55°～20°N)的SST进行了主成分分析(1951～1986年)。分析表明:前五个特征向量空间型是北太平洋SST非季节变化的主要型,它们约占海温场总方差的50％。第一特征向量空间型反映了与埃尔—尼诺现象有关的大尺度分布特征。相应的时间系数序列的变化,可以清楚地鉴别50年代以来出现的埃尔—尼诺时期。它的10阶多项式反映了历史上的变暖(变冷)和变冷(变暖)期。其余特征向量空间型,反映了占北太平洋大气活动中心(如阿留申低压和西太平洋高压)和洋流区、非洋流区有关的海温分布特征。同样,对它们的时间系数序列进行了分析讨论。最后,根据前五个时间系数的线性变化趋势。对北太平洋海温变化趋势进行了讨论。

The principal component analysis of monthly mean sea surface temperatures ( SST ) for the North Pacific between 55°N^20 °N during the perion of 1951~1986 has been performed .The analysis shows that the spatial patterns of the first five eigenvectors, explaining 50% of the total variance, are the most important modes of non-seasonal variation of SST .The first mode demonstrates the large-scale nature of the El Nino phenomenon. The time variation of the time coefficient series corresponding to this mode quite clearly identifies the distinctive El Nino periods since the 1950s. Its 10—order polynomial designates the warming (cooling) or cooling ( warming ) periods in the past time.The other important non-seasonal modes reflect the characteristics associated with the atmospheric action centers (e.g. Aleutian low pressure and western Pacific high pressure ) and the current and non-current regions of the North Pacific.And time coefficient series corresponding to these modes are also discussed .The SST trend of the North Pacific is analysed according to the linear evolution of the first five time coefficient serien.