Impact of Warming Trend in Western Equatorial Pacific on Modulating the Triple‐Dip La Niña and Its Associated Teleconnection in 2020–2022

Abstract

Abstract In this study, we investigated the triple‐dip La Niña during 2020–2022 by comparing it with the previous (1973–1975 and 1998–2000) La Niña events. We found that the cold sea surface temperature (SST) in the eastern equatorial Pacific was moderate during the study period; however, the accompanying near‐surface easterly wind anomaly was unusually stronger during its lifecycle than during the previous two events. The maintenance of 2020–2022 La Niña appeared to be attributable to the strong zonal SST gradient. The strong zonal SST gradient resulted from the La‐Niña‐associated interannual SST anomaly, which was further enhanced by a warming trend in the western equatorial Pacific (165°E−160°W, 5°S–5°N) and the interdecadal oscillation of the Pacific‐Decadal‐Oscillation‐associated cold SST in the eastern tropical Pacific. The warming trend in the western equatorial Pacific, with a faster warming speed than global warming, also modified the La‐Niña‐associated Pacific–North American teleconnection to shifted eastward.

Keywords

• triple‐dip La Niña
• zonal SST gradient
• warming trend
• Pacific Decadal Oscillation
• Pacific–North American teleconnection