Xu Xinqiang, Wang Lei, Yu Weidong
First Institute of Oceanography, and Key Laboratory of Marine Science and Numerical Modeling, Ministry of Natural Resources, Qingdao, 266061, China.
Laboratory for Regional Oceanography and Numerical Modeling, Pilot National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
Sci Rep. 2021 Mar 11;11(1):5632. doi: 10.1038/s41598-021-84936-w.
The interannual variability of the sea surface temperature (SST) in the Indian Ocean is complex and characterized by various air-sea coupled modes, which occur around El Niño/La Niña's peak phase (i.e. December-January-February, DJF). Indian Ocean Dipole Mode (IODM) develops over the tropical Indian Ocean and peaks in September-October-November (SON), while Ningaloo Niño, Subtropical Indian Ocean Dipole (SIOD) and Indian Ocean Basin Mode (IOBM) occur respectively over northwest off Australia, subtropical and tropical Indian Ocean, during boreal winter to spring. The apparent contrast between their divergent regionality and convergent seasonality around DJF triggers the present study to examine the interaction between the local mean monsoonal cycle and the anomalous forcing from El Niño/La Niña. The diagnosis confirms that the Indian Ocean's unique complexity, including the monsoonal circulation over the tropics and the trade wind over the subtropical southern Indian Ocean, plays the fundamental role in anchoring the various regional air-sea coupled modes across the basin. The SST anomalies can be readily explained by the wind-evaporation-SST (WES) mechanism, which works together with other more regional-dependent dynamic and thermodynamic mechanisms. This implies that El Niño/La Niña brings much predictability for the Indian Ocean variations.
印度洋海表温度（SST）的年际变化较为复杂，具有多种海气耦合模式的特征，这些模式出现在厄尔尼诺/拉尼娜的高峰期（即12月至次年1月至2月，DJF）左右。印度洋偶极子模式（IODM）在热带印度洋发展，并在9月至10月至11月（SON）达到峰值，而宁加洛厄尔尼诺、亚热带印度洋偶极子（SIOD）和印度洋海盆模式（IOBM）分别在澳大利亚西北部、亚热带和热带印度洋出现，发生在北半球冬季至春季。它们在DJF附近不同的区域分布和趋同的季节性之间的明显差异引发了本研究，以探讨当地平均季风周期与厄尔尼诺/拉尼娜异常强迫之间的相互作用。诊断结果证实，印度洋独特的复杂性，包括热带地区的季风环流和亚热带南印度洋的信风，在固定整个海盆的各种区域海气耦合模式中起着根本性作用。海表温度异常可以很容易地用风-蒸发-海表温度（WES）机制来解释，该机制与其他更多依赖区域的动力和热力机制共同作用。这意味着厄尔尼诺/拉尼娜为印度洋变化带来了很大的可预测性。
