We examine the transition processes of El Niño occurring in 1 year after using observations, a multi-century model simulation and atmospheric general circulation model (AGCM) experiments. One type is characterized by a quick transition from an El Niño event into a La Niña event in the following winter, and the other type involves a slow decay to an almost neutral state or a continuous El Niño event. While both the Indian and the Atlantic Oceans contribute to the El Niño’s transition processes, we further find that sea surface temperature (SST) conditions in the eastern subtropical North Pacific and the associated surface wind anomalies play important roles in determining the different types of El Niño’s transition processes through atmosphere–ocean coupled processes. In particular, northeasterly wind anomalies in the central subtropical North Pacific during the early spring, which is in consequence of atmosphere–ocean coupled processes, contribute to decreasing ocean heat content (OHC) anomalies and strengthening easterly wind anomalies in the central tropical Pacific. These anomalies lead up to a transition into a La Niña event in the following winter. On the contrary, weakening of the northeasterly wind and warm SST anomalies in the eastern subtropical North Pacific during the early spring are conducive to a neutral state or a continuous El Niño event in the subsequent winter. Similar transition processes are also found in a multi-century model simulation. By conducting idealized AGCM experiments, we also show that the anomalous SST in the eastern subtropical North Pacific during El Niño peak season may induce surface wind anomalies in the central tropical Pacific during El Niño onset season. These results provide potential precursors for predicting the occurrence of a La Niña event, a neutral state and an El Niño event 1 year after the occurrence of an El Niño event.

我们使用观测，多世纪模型模拟和大气总循环模型（AGCM）实验，研究了厄尔尼诺现象在1年内发生的转变过程。一种类型的特征是在下一个冬季从厄尔尼诺事件迅速过渡到拉尼娜事件，另一种类型则涉及缓慢衰减到几乎中性状态或连续的厄尔尼诺事件。尽管印度洋和大西洋都对厄尔尼诺现象的过渡过程做出了贡献，但我们进一步发现，东亚热带北太平洋的海表温度（SST）条件以及相关的地表风异常在确定厄尔尼诺现象的不同类型中起着重要作用。通过大气-海洋耦合过程的过渡过程。特别是，早春期间，中亚热带北太平洋的东北风异常是大气-海洋耦合过程的结果，有助于降低海洋热量含量（OHC）异常，并增强热带中部太平洋的东风异常。这些异常导致下个冬季过渡为拉尼娜事件。相反，早春东北亚热带北太平洋东北风和暖SST异常的减弱有利于中性状态或随后冬季的连续厄尔尼诺事件。在多世纪的模型仿真中也发现了类似的过渡过程。通过进行理想的AGCM实验，我们还表明，在厄尔尼诺现象高峰季节期间，东亚热带北太平洋海温异常可能在厄尔尼诺现象发作季节诱发了热带中部太平洋的地面风异常。这些结果为预测厄尔尼诺事件发生1年后发生拉尼娜事件，中立状态和厄尔尼诺事件提供了潜在的先兆。