Potential ocean atmosphere preconditioning of late autumn Barents-Kara sea ice concentration anomaly

Many recent studies have revealed the importance of the climatic state in November on the seasonal climate of the subsequent winter. In particular, it has been shown that interannual variability of sea ice concentration (SIC) over the Barents-Kara (BK) seas in November is linked to winter atmospheric circulation anomaly that projects on the North Atlantic Oscillation. Understanding the lead lag processes involving the different components of the climate system from autumn to winter is therefore important. This note presents dynamical interpretation for the ice-oceanatmosphere relationships that can affect the BK SIC anomaly in late autumn. It is found that cyclonic (anticyclonic) wind anomaly over the Arctic in October, by Ekman drift, can be responsible for positive (negative) SIC in theBKseas in November. The results also suggest that ocean heat transport via the Barents Sea Opening in September and October can contribute to BK SIC anomaly in November.JG-S has been supported by the European Union’s FP7-funded NACLIM project (ENV-308299) and H2020-funded DPETNA grant (MSCA-IF-EF 655339). MPK acknowledges the Severo Ochoa Visiting Fellowship at the Barcelona Supercomputing Center and the Nordforsk GREENICE project (61841). Mehmet Ilicak and MariusA˚ rthun provided suggestions related to ocean heat transport. Suggestions from the reviewer had also led to improvement in the analyses.Peer Reviewe