Dynamics for El Nino-La Nina asymmetry constrain equatorial-Pacific warming pattern
Dynamics for El Nino-La Nina asymmetry constrain equatorial-Pacific warming pattern
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DOI：
10.1038/s41467-020-17983-y
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发表时间：
2020-08-28
影响因子：
16.6
通讯作者：
Stuecker, Malte F.
中科院分区：
文献类型：
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作者：
Hayashi, Michiya;Jin, Fei-Fei;Stuecker, Malte F.
厄尔尼诺-南方涛动（ENSO）是热带太平洋冷舌不稳定的结果，同时也调节着热带太平洋冷舌的强度。虽然气候模型相对较好地再现了观测到的 ENSO 幅度，但大多数模型仍然很难模拟暖期（厄尔尼诺）和冷期（拉尼娜）之间的不对称性。迄今为止，这一重大缺陷的原因及其后果尚不清楚。通过分析再分析和气候模型，我们发现模拟的 ENSO 不对称性在很大程度上与赤道太平洋温跃层的地下非线性动力加热 (NDH) 成正比。大多数气候模型都存在 NDH 过弱和线性动力海洋-大气耦合过弱的问题。然而，具有相对现实的 NDH 的相当大的子集（约 1/3）表明，赤道-太平洋变暖模式的厄尔尼诺现象与响应温室变暖的 ENSO 幅度变化呈线性相关。因此，更好地模拟 ENSO 不对称的动态可能会减少未来预测的不确定性。
The El Nino-Southern Oscillation (ENSO) results from the instability of and also modulates the strength of the tropical-Pacific cold tongue. While climate models reproduce observed ENSO amplitude relatively well, the majority still simulates its asymmetry between warm (El Nino) and cold (La Nina) phases very poorly. The causes of this major deficiency and consequences thereof are so far not well understood. Analysing both reanalyses and climate models, we here show that simulated ENSO asymmetry is largely proportional to subsurface nonlinear dynamical heating (NDH) along the equatorial Pacific thermocline. Most climate models suffer from too-weak NDH and too-weak linear dynamical ocean-atmosphere coupling. Nevertheless, a sizeable subset (about 1/3) having relatively realistic NDH shows that El Nino-likeness of the equatorial-Pacific warming pattern is linearly related to ENSO amplitude change in response to greenhouse warming. Therefore, better simulating the dynamics of ENSO asymmetry potentially reduces uncertainty in future projections.