北太平洋SST场的客观区划及其时频相关性

本文采用方差极大正交旋转的因子分析方法,对北太平洋SST场进行客观区划,结果表明,北太平洋SST场可划分为五大海区,即(Ⅰ)赤道东太平洋海区;(Ⅱ)加利福尼亚北信风海区;(Ⅲ)太平洋西部区;(Ⅳ)太平洋北部区;(Ⅴ)太平洋中部区。这些海区分别与整个北太平洋洋流和热通量空间分布具有很好的对应。其中海区(Ⅰ)在北太平洋SST场占有最重要的地位,它常年稳定少变,对SST场贡献最大。文中进一步对各海区SST时间序列作功率谱和交叉谱分析,得到有关各海区SST月际振动的显著周期和各海区之间显著的耦合振荡周期。计算表明,在这些时频相关性特征中,最为重要的周期振动和耦合振荡都与海区(Ⅰ)即赤道东太平洋海区有关。

OBJECTIVE REGIONALIZATION OF SST FIELD IN NORTHERN PACIFIC AND ITS CORRELATION FEATURES IN THE TIME & FREQUENCY DOMAIN

An objectve regionalization of SST field in Northern Pacific is set up using the orthogonally rotated factor analysis based on maximum variance criterion. The result shows that the whole Northern Pacific SST field may be divided into five regions: (1) the equatorial eastern Pacific region; (2) the north trade wind region off California; (3) the western Pacific region; (4) the northern Pacific region; (5) the central Pacific region. It is obvious that the regions correspond well with ocean currents and spatial distribution of thermal flux for the whole nortern Pacific. In particular, Region (1) is stable and has the maximum weight in the whole SST field for Northern Pacific and contributes most to it by being secularly stable. Furthermore,from the power and cross spectra of the SST time series,significant periods in inter-monthly SST oscillations for individual regions and marked coupling ones among them are derived. Characteristic of time-frequency correlation , all dominant oscillations are associated with Region (1) .