Interannual variability of lower equatorial intermediate current response to ENSO in the western Pacific
Interannual variability of lower equatorial intermediate current response to ENSO in the western Pacific
复制标题
西太平洋下赤道中流对ENSO响应的年际变化
DOI：
10.1029/2020gl089311
复制
发表时间：
2020
影响因子：
5.2
通讯作者：
Lyu Yilong
中科院分区：
文献类型：
--
作者：
Ma Qiang;Wang Jianing;Wang Fan;Zhang Dongxiao;Zhang Zhixiang;Lyu Yilong
热带太平洋的洋流随厄尔尼诺-南方涛动（ENSO）周期而变化。2014-2018年在西太平洋获得的系泊时间序列显示，年际变化延伸到下赤道中间流（LEIC）。LEIC速度异常与11个月滞后的Niño-3.4指数显著相关。1993-2018年期间，来自全球海洋物理再分析产品和线性连续分层海洋模型的每月速度数据捕获了2015-2016年的信号，并用于确定潜在机制。在厄尔尼诺（La Niña）事件期间，第一个秋冬季节热带太平洋中部的直接风强迫和东太平洋Kelvin波的反射共同导致了第二个秋冬季节西太平洋的东（向西）向流异常。这一过程主要是通过第二斜压模态和离赤道向西传播的下降流（上升流）Rossby波的产生来实现的。
The ocean currents of the tropical Pacific Ocean vary with El Niño‐Southern Oscillation (ENSO) cycles. A mooring time series obtained during 2014–2018 in the western Pacific reveal that interannual variability extends to Lower Equatorial Intermediate Current (LEIC). The LEIC velocity anomalies are significantly correlated with the Niño‐3.4 index at an 11‐month lag. Monthly velocity data from the global ocean physical reanalysis product and from a linear continuously stratified ocean model during 1993–2018 capture the 2015–2016 signal and are used to identify the underlying mechanism. During El Niño (La Niña) events, the direct wind forcing in the central tropical Pacific and the reflection of Kelvin waves in the eastern Pacific during the first autumn‐winter period contribute comparably to an eastward (westward) current anomaly in the western Pacific during the second autumn‐winter period. This process is achieved mainly through the generation of the second baroclinic mode and off‐equatorial westward‐propagating downwelling (upwelling) Rossby waves.