Distinct Roles of Arctic Sea Ice and Global Sea Surface Temperatures in the Phased Evolution of the Winter Arctic–Midlatitude Air Temperature Linkage

Abstract Through CAM5.4 simulations, this study investigates the distinct roles of Arctic sea ice and global sea surface temperatures (SSTs) in the phased evolution of the winter Arctic‐midlatitude air temperature linkage. Results show that Arctic sea ice melting favored the interdecadal intensification of the warm Arctic‐cold Eurasia (WACE) pattern during the winters from 2004 to 2012, whereas global SST forcing favored the phased intensification of the warm Arctic‐warm Eurasia (WAWE) pattern since the winter of 2013. Further analysis reveals that Arctic sea ice melting facilitated the weak‐strong‐weak phased evolution of the linkage between the Barents‐Kara Seas (BKS) and East Asian temperatures since the winter of 1979, whereas global SST forcing primarily contributed to the weakening of this linkage since the winter of 2013. Quantitative analysis shows that from the winters of 1979–2003 (P1) to 2004–2012 (P2), models forced with observed sea ice (ASIC) reproduced 39.4% of the observed Arctic warming and 11.1% of the observed East Asian cooling, while models forced with global SSTs (GSST) showed a weak Arctic cooling and East Asian warming. From the winters of 2004–2012 (P2) to 2013–2024 (P3), GSST reproduced 49.7% of the observed Arctic warming, surpassing the 37.9% from ASIC. More importantly, GSST reproduced 75.4% of the East Asian warming and captured the interdecadal transition from the WACE to the WAWE configuration during P3, whereas ASIC showed East Asian cooling.