Influence of winter Arctic sea ice concentration change on the El Niño–Southern Oscillation in the following winter

Abstract

The present study reveals a close connection between the winter Arctic sea ice concentration (ASIC) change over the Greenland–Barents Seas (GBS) and the El Nino–Southern Oscillation (ENSO) in the following winter. When there is more winter ASIC over the GBS, an El Nino-like sea surface temperature (SST) warming tends to occur in the tropical central-eastern Pacific (TCEP) during the following winter. It is found that the winter ASIC increase over the GBS triggers an atmospheric wave train propagating southeastward from the high latitude Eurasia towards the subtropical North Pacific, with cyclonic wind anomalies over the subtropical North Pacific. A barotropic model experiment with anomalous convergence prescribed around the GBS reproduces reasonably well the atmospheric wave train. The induced spring SST warming and associated anomalous atmospheric heating over the subtropical North Pacific play an essential role in the formation and maintenance of lower-level westerly wind anomalies over the western tropical Pacific. These westerly wind anomalies induce SST warming in the TCEP during the following summer via triggering an eastward propagating equatorial warm Kelvin wave. The summer TCEP SST warming further develops into an El Nino event in the following winter via a Bjerknes-like positive air–sea feedback process. This result suggests that the winter ASIC change around the GBS is a potential predictor of the ENSO events with a lead time of 1 year.