Will the Historic Southeasterly Wind over the Equatorial Pacific in March 2022 Trigger a Third-year La Niña Event?

Based on the updates of the Climate Prediction Center and International Research Institute for Climate and Society (CPC/IRI) and the China Multi-Model Ensemble (CMME) El Niño-Southern Oscillation (ENSO) Outlook issued in April 2022, La Niña is favored to continue through the boreal summer and fall, indicating a high possibility of a three-year La Niña (2020–23). It would be the first three-year La Niña since the 1998–2001 event, which is the only observed three-year La Niña event since 1980. By examining the status of air—sea fields over the tropical Pacific in March 2022, it can be seen that while the thermocline depths were near average, the southeasterly wind stress was at its strongest since 1980. Here, based on a quaternary linear regression model that includes various relevant air-sea variables over the equatorial Pacific in March, we argue that the historic southeasterly winds over the equatorial Pacific are favorable for the emergence of the third-year La Niña, and both the anomalous easterly and southerly wind stress components are important and contribute ∼50% of the third-year La Niña growth, respectively. Additionally, the possible global climate impacts of this event are discussed.