赤道潜流变化及其与ENSO的关系  

Variations of equatorial undercurrent and its relationship with ENSO cycle

作　　者：王宏娜[1,2,3] 陈锦年[1,2,4] 何宜军[1,2] 

机构地区：[1]中国科学院海洋研究所,山东青岛266071 [2]中国科学院海洋环流与波动重点实验室,山东青岛266071 [3]中国科学院研究生院,北京100049 [4]中国气象局广州热带海洋气象研究所,广东广州510080

出　　处：《海洋学报》2009年第3期1-11,共11页

基　　金：国家自然科学基金(40676017);中国科学院知识创新工程重要方向项目(KZCX2-YW-Q11-02;KZCX2-YW-214)资助

摘　　要：应用TOGA/TAO实测海流和SODA全球海洋再分析资料,分析研究了热带太平洋赤道潜流的变化特征及其与ENSO循环的关系,初步探讨了赤道潜流变化对两种不同类型(中部型和东部型)ENSO事件的影响。对赤道潜流距平场的EOF分解表明,第一模态为"东太平洋潜流模态",特征向量主要反映东太平洋赤道潜流的变化情况;第二模态为"中太平洋潜流模态",特征向量主要反映中太平洋赤道潜流的变化情况;这两个主要模态基本可以反映赤道潜流距平场的主要信息。这两个模态对应的时间系数有明显的年际变化特征,并且与NINO指数都有较好的负相关,最大相关均通过99.9%的信度检验。相关分析表明潜流第一模态的变化滞后于NINO指数变化,而第二模态的变化则提前于NINO指数变化,即ENSO事件对东太平洋赤道潜流的变化有一定影响,而中太平洋的潜流变化又会对ENSO事件产生影响。通过个例分析表明,中太平洋赤道潜流的变化对两种不同类型ENSO事件的发生有重要影响。在东部型ENSO事件发生前,中太平洋赤道潜流增强,这样西太平洋暖池的异常海温在潜流的引导下快速向东传播,直接到达东太平洋形成东部型ENSO事件;中部型ENSO事件发生前,中太平洋赤道潜流明显减弱,西太平洋的异常海温不能迅速东传速,在中太平洋堆积上升到达海面,使得中部型ENSO事件爆发。The variability of equatorial undercurrent in tropical Pacific and its relationship with ENSO cycle were analyzed using velocity data from Tropical Ocean and Global Atmosphere-Tropical Atmosphere Ocean array and Simple Ocean Data Assimilation dataset. The influence of equatorial undercurrent on different pattern ENSO events （eastern pattern and central pattern） was tentatively discussed. The result of Empir- ical Orthogonal Function （EOF） analysis for the anomaly of equatorial undercurrent showed that the char- acteristic vector of first mode mainly reflected the variability of Eastern Pacific equatorial undercurrent and the second mode mainly reflected the variability of Central Pacific equatorial undercurrent. These two main modes could show the basic variability of equatorial undercurrent in the Pacific Ocean. The time coeffi- cients of the two modes have obvious interannual variability and they have obvious negative correlations with the NINO index. It revealed that the influence of ENSO cycle on the equatorial undercurrent was shown mainly by the variability of Eastern Pacific undercurrent. And the equatorial undercurrent affected the ENSO events by the variability of Central Pacific undercurrent. The variation of undercurrent in the central pacific has important influence on the different pattern ENSO events. In the ENSO cycle, when the equatorial undercurrent singularly increased in central Pacific, the anomalous temperature in western Pacific subsurface propagated to the east and the SSTA reached eastern Pacific, so the eastern pattern ENSO events occurred. Contrarily when the equatorial undercurrent decreased in central Pacific, the anomalous seawater gathered in central Pacific making the sea surface temperature anomaly in central Pacific first, so the central pattern ENSO events occurred.

关 键 词：赤道潜流 EOF分解 两类ENSO事件 

分 类 号：Q179.1[生物学—水生生物学]