The Modeled Winter Sea Ice-Atmosphere Feedback over the Barents Sea

The sea ice-atmosphere feedback over the Barents Sea was studied in a modeling framework by decomposing the feedback into two sequential boundary forcing experiments. The standalone Community Ice CodE (CICE) model was initialized with anomalously high sea ice concentration (SIC) over the Barents Sea and forced with atmospheric conditions generated by daily-varying positive Barents Sea SIC anomalies that decayed throughout the winter. Likewise, CICE was initialized with anomalously low SIC over the Barents Sea and forced with atmospheric conditions generated by negative Barents Sea SIC anomalies. Corresponding control runs were produced by exposing the high-SIC and low-SIC initial conditions to climatological atmospheres. The monthly mean sea ice response was positive over the Barents Sea for both experiments: the atmosphere produced by positive SIC anomalies increased SIC over the Barents Sea during the winter, and the atmosphere produced by negative SIC anomalies decreased SIC. The positive feedback was primarily thermodynamically-driven by surface longwave flux anomalies, and opposed by low-level temperature advection. Dynamical effects also opposed the positive feedback, with enhanced surface wind stress divergence over the Barents Sea in the high-SIC case, and enhanced convergence in the low-SIC case.