A modeling investigation of the Arctic sea ice-atmosphere feedback

We examine the effects of a general sea ice-atmosphere feedback (SAF) over the Barents Sea by turning it on and off in a coupled climate model. The SAF is “turned off” by forcing the atmosphere with surface turbulent and longwave heat fluxes and surface temperatures that reflect climatological sea ice cover over the Barents Sea, while allowing the sea ice and sea surface temperature (SST) to freely evolve. Suppressing the SAF reduces the variability of near-surface air temperature (T), sea ice concentration (I) , and SST averaged over the Barents Sea by up to 35 %, confirming the existence of a positive thermodynamically-driven SAF found in prior uncoupled modeling studies. Decreased interannual variability accounts for most of the total reduction in I, T, and SST variability, and the largest reductions in variability occur during the winter sea ice growth and spring melt seasons. In contrast to the results from the coupled model experiment, the total variances of I, T, and SST do not significantly change in response to suppressing the SAF in a simple vector autoregressive model, indicating that the SAF is nonlinear.