西太平洋暖池水体振荡与赤道中东太平洋海表温度异常的关联性初探

The relationship between the oscillation of western Pacific warm pool and sea surface temperature anomalies in equatorial central and eastern Pacific

赤道中东太平洋海表温度异常是研究ENSO(El Ni?o-South Oscillation)的重要指标。本文利用海洋再分析数据,着眼于西太平洋暖池暖水体三维结构的年际变异特征,分析西太平洋暖池水体变动与赤道中东太平洋海表温度异常的关联性,并从前期西太平洋暖池三维暖水体的结构演变及其在上层海洋质量与热量配置中的作用角度,探究了赤道中东太平洋关键Ni?o分区海表温度异常变化的内在一致性,以期为ENSO的预测预报提供新的思路和依据。分析表明,ENSO尺度上西太平洋暖池三维结构变异主模态表现为暖水体平均约以170oE为轴的纬向时空振荡,其可超前赤道中东太平洋海表温度异常变化约达6个月,并以在赤道中东太平洋及附近海域形成双舌状异常"暖池"为显著特征。前期暖池暖水体的纬向振荡是赤道中东太平洋海表温度异常变化的重要前兆信息之一。作为海洋中ENSO暴发的重要源区和驱动因子,西太平洋暖池纬向振荡通过在中东太平洋形成不同强度(泛指暖水量及其深度和范围等的大小)的异常"暖池",进而在上层海洋质量和热量的纬向配置中起关键性作用,并且可能与不同EI Ni?o事件的触发机制密切相关,从这种意义上讲,不同ENSO事件的发生和发展存在一定的同源一致性。

The anomalies of sea surface temperature（SST） in equatorial central and eastern Pacific are important indexes for the research of ENSO（El Ni？o-South Oscillation）,. Based on the oceanic reanalysis, the relationship between the fluctuations of the warm water（T≥28℃） of the western Pacific warm pool（WPWP） and SST anomalies in equatorial central and eastern Pacific was investigated with focus on the interannual variability of the three-dimensional WPWP warm water, and from the view of the evolution of three-dimensional distribution of the WPWP warm water preceding the emergence of SST anomalies in key Ni？o regions and its important role in controlling the pattern of mass and heat in upper ocean, the intrinsic consistency among the anomalous changes in SST in equatorial central and eastern Pacific was probed into, which was expected to provide the new clue and basis for the mechanism and forecast of ENSO. The analysis suggests that the dominant pattern of spatio-temporal variation on ENSO time- scale as for three-dimensional WPWP warm water is the zonal oscillation with a zonal-averaged equilibrium line around 170 oE. At the same time, its remarkable characteristic is the formation of an anomalous double cantilever ＂warm pool＂ in the central and eastern tropical Pacific at the early stage（leading by around 6 months） of variations of SST anomalies in key Nino regions. The interannual zonal oscillation of the WPWP warm water is one of prerequisites for the anomalous changes of SST in key Nino regions. In virtue of the development of the anomalous ＂warm pool＂ with different intensity（generally refer to the volume of warm water and the magnitude of warm water depth and extent） in central and eastern Pacific which favors the zonal reconfiguration of the mass and heat in the upper ocean, the WPWP zonal oscillation is very likely to play decisive role as a original driver in the ocean to trigger the different EI Nino events, namely, that there is a sense in which the different flavors of ENSO events are to a great extent homeomorphous.