西北太平洋上层热含量的时空变化

Spatial and Temporal Variations in the Upper Layer Heat Content Field Over the Northwestern Pacific Ocean

基于全球月平均海温资料、137°E断面海温观测资料、同化水位资料和太平洋850hPa纬向风资料,利用EOF、功率谱和最大熵谱等分析方法,分析了西北太平洋上层热含量的时空变化,并讨论了热含量变化与水位和赤道太平洋纬向风异常的关系。结果表明,西北太平洋上层热含量具有明显的年际和年代际变化;热含量的年际变化与热带太平洋大尺度海气系统异常相联系,即在ElNio期间,热含量减少,而在LaNia期间热含量增多;热含量在20世纪70年代末发生了一次气候跃变,在跃变前热含量偏多,而在跃变后则偏少;热含量与水位间存在着非常一致的同位相年际变化,而这种变化与赤道西、中太平洋的纬向风异常有关。

Based on the monthly mean sea temperature dataset of the global oceans, the observed tempera- ture data along the 137°E section, the sea surface level data from SODA reanalysis dataset, and the 850hPa zonal wind data over the equatorial Pacific Ocean, the spatial and temporal variations of the upper layer （0-400 m） heat content anomaly field over the northwestern Pacific Ocean（0°-35°N, 120°-180°E）are studied by means of empirical orthogonal function（EOF）, power spectral analysis, and maximum entropy spec- tral analysis, and the relationships among the heat content, the sea surface level, and the zonal wind a- nomaly also are discussed. The results show that the upper layer heat contents in the northwestern Pacific Ocean have obvionsly interannual and interdecadal variations. The interannual variation in the heat content is associated with the large scale air-sea system of the tropical Pacific Ocean. Namely, the heat content de creases during E1 Nifio and increases during La Nifia. The heat content underwent a climate change in the late 1970s, i.e. the heat content is higher before the change and lower after it. The heat contents has its interannual variation in phase with the sea surface level variation, which is associated with the zonal wind anomalies over the western and central equatorial Pacific Ocean.