Impact of the Indian Ocean Dipole on Evolution of the Subsequent ENSO: Relative Roles of Dynamic and Thermodynamic Processes
Impact of the Indian Ocean Dipole on Evolution of the Subsequent ENSO: Relative Roles of Dynamic and Thermodynamic Processes
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DOI：
10.1175/jcli-d-20-0487.1
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发表时间：
2021-02
影响因子：
4.9
通讯作者：
Zhang Yue;Wen Zhou;Tim Li
中科院分区：
文献类型：
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作者：
Zhang Yue;Wen Zhou;Tim Li
本文进一步研究了印度洋偶极子（IOD）与厄尔尼诺-南方涛动（ENSO）之间的复杂相互作用，重点研究了IOD对ENSO（+1）的影响。IOD与ENSO [ENSO（0）]之间的相互作用可以概括为：ENSO（0）可以触发和增强IOD，而IOD可以增强ENSO（0）并加速其消亡。IOD（0）对ENSO（+1）的影响表明，IOD（0）可导致冬季后赤道太平洋海温异常变冷，并在次年形成类似La Niña的环流型。虽然SST冷却趋势与正IOD主要是由于净热通量（热力学过程）从秋季到次年春季，次年春季后的主要贡献来自海洋过程（动力学过程），而不是。从秋季到次年春季，由于云-辐射-SST的反馈作用，向下的短波通量响应对中太平洋和东太平洋SST冷却的贡献最大。从随后的冬季到随后的夏季，潜热通量（LHF）的变化是重要的SST冷却，表明LHF从海洋释放到大气中的增加，由于强烈的蒸发，并导致SST冷却通过风-蒸发-SST反馈。风应力响应和温跃层变浅证实了局地Bjerknes反馈对拉尼娜后期的启动至关重要。
The complex interaction between the Indian Ocean dipole (IOD) and El Niño–Southern Oscillation (ENSO) is further investigated in this study, with a focus on the impacts of the IOD on ENSO in the subsequent year [ENSO(+1)]. The interaction between the IOD and the concurrent ENSO [ENSO(0)] can be summarized as follows: ENSO(0) can trigger and enhance the IOD, while the IOD can enhance ENSO(0) and accelerate its demise. Regarding the impacts of IOD(0) on the subsequent ENSO(+1), it is revealed that the IOD can lead to anomalous SST cooling patterns over the equatorial Pacific after the winter following the IOD, indicating the formation of a La Niña–like pattern in the subsequent year. While the SST cooling tendency associated with a positive IOD is attributable primarily to net heat flux (thermodynamic processes) from autumn to the ensuing spring, after the ensuing spring the dominant contribution comes from oceanic processes (dynamic processes) instead. From autumn to the ensuing spring, the downward shortwave flux response contributes the most to SST cooling over the central and eastern Pacific, due to the cloud–radiation–SST feedback. From the ensuing winter to the ensuing summer, changes in latent heat flux (LHF) are important for SST cooling, indicating that the release of LHF from the ocean into the atmosphere increases due to strong evaporation and leads to SST cooling through the wind–evaporation–SST feedback. The wind stress response and thermocline shoaling verify that local Bjerknes feedback is crucial for the initiation of La Niña in the later stage.