Decay of the El Niño with Different Intensity. Part II, Decay of the Moderate and Relatively‐Weak El Niño

In Part II, we explored the decay processes of the moderate and relatively-weak El Nino. The results show that for the moderate El Nino, the anomalous signals appear in the development and peak phase, then they decay quickly after the peak phase due to the insufficient intensity of the El Nino. This is similar to the abortion of the western Pacific oscillation process. For this reason, different from the strong El Nino, the moderate El Nino turns into a normal state. For the relatively-weak El Nino, its phase transition is controlled by another mechanism. With the enhancement and westward movement of the subtropical high over the southeastern Pacific, the easterly and sea surface temperature anomalies also extend westward from the tropical eastern Pacific. The above process is an advective mode that causes the relatively-weak El Nino turning into a La Nina.