Distinct impacts of major El Niño events on Arctic temperatures due to differences in eastern tropical Pacific sea surface temperatures.

ABSTRACT

The El Niño Southern Oscillation (ENSO) is a climate mode in the tropical Pacific. The ENSO teleconnections are known to affect Arctic temperature; however, the robustness of this relationship remains debated. We find that Arctic surface temperatures during three major El Niño events are remarkably well simulated by a state-of-the-art model when nudged to the observed pantropical sea surface temperatures (SSTs). SST perturbation experiments show that the 1982-1983 warm pan-Arctic and the 1997-1998 cold pan-Arctic during winter can be explained by far eastern equatorial Pacific SSTs being higher during 1997-1998 than 1982-1983. Consistently, during the 2017-2018 La Niña, unusually low SSTs in the same region contributed to pan-Arctic warming. These pan-Arctic responses to the SSTs are realized through latent heating anomalies over the western and eastern tropical Pacific. These results highlight the importance of accurately representing SST amplitude and pattern for Arctic climate predictions.