西太平洋暖池海域上层海洋热盐含量初步研究

基于2001年1月～2014年7月期间的Argo温盐剖面资料，利用循环平稳经验正交函数（CSEOF）分解、最大熵谱分析和相关分析等方法，研究了西太平洋暖池海域上层海洋热盐含量的空间分布、季节和年际变化特征，并探讨了其影响机制。结果表明，暖池海域近表层与次表层热含量逐年变化呈反位相变化模态，同样盐含量变化趋势也不尽相同。无论热含量还是盐含量，都存在着明显的季节和年际变化。CSEOF分析表明，暖池海域热含量第一模态空间场具有显著的东—西反相位年际振荡，盐含量第一模态则呈正-负-正的三极子模态，但时间序列显示，热含量在2007年以后经过3次位相调整，而盐含量2007年以后只经过一次位相调整，且这种年际变化都与ENSO事件有关，且热含量相比于盐含量受ENSO影响更大。El Niño期间，暖池海域西部热含量减少， 东部增加，La Niña期间则相反；研究海域南北部盐含量在El Niño期间增加，中部（暖池高温中心）减少，La Niña期间则相反；进一步分析表明，热含量变化主要受到局地风场以及纬向流的影响，而盐含量变化则受淡水通量和纬向流的影响。

A preliminary study on an upper ocean heat and salt content of the western Pacific warm pool region

On the basis of Argo profile data of the temperature and salinity from January 2001 to July 2014, the spatial distributions of an upper ocean heat content (OHC) and ocean salt content (OSC) of the western Pacific warm pool (WPWP) region and their seasonal and interannual variations are studied by a cyclostationary empirical orthogonal function (CSEOF) decomposition, a maximum entropy spectral analysis, and a correlation analysis. Probable reasons for variations are discussed. The results show the following. (1) The OHC variations in the subsurface layer of the WPWP are much greater than those in the surface layer. On the contrary, the OSC variations are mainly in the surface layer, while the subsurface layer varies little. (2) Compared with the OSC, the OHC of the WPWP region is more affected by El Niño-Southern Oscillation (ENSO) events. The CSEOF analysis shows that the OHC pattern in mode 1 has strong interannual oscillation, with eastern and western parts opposite in phase. The distribution of the OSC has a positive-negative-positive tripole pattern. Time series analysis shows that the OHC has three phase adjustments with the occurrence of ENSO events after 2007, while the OSC only had one such adjustment during the same period. Further analysis indicates that the OHC variations are mainly caused by ENSO events, local winds, and zonal currents, whereas the OSC variations are caused by much more complex reasons. Two of these, the zonal current and a freshwater flux, have a positive feedback on the OSC change in the WPWP region.