Weakened relationship between November Barents-Kara sea ice and January Arctic Oscillation after the mid-1990s

Abstract

The Arctic Oscillation (AO) is a dominant atmospheric mode in the Northern Hemisphere, influencing weather and climate. Its variations are driven by numerous factors, including Arctic sea ice, particularly autumn Barents-Kara Sea ice concentration (SIC), which can significantly impact the AO through planetary wave dynamics. However, the interdecadal stability of this relationship remains unclear. This study detected the weakened November Barents-Kara SIC-January AO connection after the mid-1990s. Observational and model analysis showed that from 1979 to 1994, their relationship was driven by the North Atlantic tripole (NAT) sea surface temperature (SST) anomalies, which influenced storm track activities over North Atlantic and Eurasia, thus inducing a wave train resembling the Scandinavian pattern. After the mid-1990s, weakened interannual variability of the NAT SST anomalies disrupted this mechanism. These findings highlight the critical role of mid-latitude ocean-atmosphere interactions in Arctic climate variability and emphasize the need for further research on long-term AO-SIC linkages.