The observed El Niño and La Niña exhibit different complexities in their event‐to‐event transition patterns. The El Niño is dominated in order by episodic, cyclic, and multiyear transitions, but the reversed order is found in the La Niña. A subtropical Pacific onset mechanism is used to explain this difference. This mechanism triggers El Niño/La Niña events via subtropical processes and is responsible for producing multiyear and episodic transitions. Its nonlinear responses to the tropical Pacific mean state result in more multiyear transitions for La Niña than El Niño and more episodic transitions for El Niño than La Niña. The CMIP5/6 models realistically simulate the observed transition complexity of El Niño but fail to simulate the transition complexity of La Niña. This deficiency in CMIP5 models arises from a weaker than observed subtropical onset mechanism and a cold bias in the tropical Pacific mean sea surface temperatures in the models.

中文翻译：

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厄尔尼诺现象和拉尼娜现象之间的对比过渡复杂性：观测值和CMIP5 / 6模型

观测到的厄尔尼诺现象和拉尼娜现象在事件到事件的过渡方式上表现出不同的复杂性。厄尔尼诺现象的发生顺序是周期性，周期性和多年过渡，但在拉尼娜现象中却相反。亚热带的太平洋发病机制被用来解释这种差异。该机制通过亚热带过程触发了厄尔尼诺/拉尼娜事件，并负责产生多年期和情节性过渡。它对热带太平洋平均状态的非线性响应导致拉尼娜的多年转变比厄尔尼诺现象多，厄尔尼诺的情节转变比拉尼娜更多。CMIP5 / 6模型实际上模拟了观察到的厄尔尼诺现象的过渡复杂性，但未能模拟出拉尼娜现象的过渡复杂性。