热带西太平洋海域上层海洋热含量的CSEOF分析

CSEOF analysis of the upper ocean heat content over tropical western Pacific

基于月平均Argo温、盐度剖面、纬向风和Ni o3.4指数等资料,利用循环平稳经验正交函数(CSEOF)分解法、最大熵谱分析和相关分析等方法,研究了热带西太平洋海域上层(0—700m)海洋热含量的时空变化特征,并探讨了其年际变化的可能原因。结果表明,热带西太平洋海域上层海洋热含量距平场具有显著的东-西向反位相振荡,且这种振荡除了具有较明显的季节变化外,还存在着较强的准2a振荡。此外,热含量距平场还存在着"负-正-负"的三极式经向模态,该模态除了具有明显的季节变化外,还存在着显著的准4a振荡。进一步分析表明,热含量的准2a振荡与ENSO事件的发生有着非常密切的联系,并对赤道西太平洋纬向风异常有1—2月的滞后响应。

The spatial and temporal distribution of the upper（0 700 m） ocean heat content（UOHC） over the tropical western Pacific and the probable causes for the variation are studied,using gridded monthly mean Argo profiling dataset from the JMESTC（Japan Marine-Earth Science and Technology Center）,zonal wind data,SST data and SSH（Sea Surface Height） data.The research tools include cyclostationary empirical orthogonal function（CSEOF） analysis,Maximum Entropy Method（MEM） and correlation analysis.The main results indicate that the UOHC anomaly of the tropical western Pacific has an east-west anti-phase oscillation and remarkable seasonal and bi-annual variation.Moreover,the UOHC anomaly displayed a sharper ＂negative-positive-negative＂ undulation,which had obvious seasonal and inter-annual（~4a） changes.With further analysis,we find that the bi-annual oscillation was highly related to the ENSO（El Nino-Southern Oscillation） events and displayed a lagged response of about 1 2 months to the local zonal wind anomaly.