Sea-Ice Climate Feedbacks in a Coupled Cell Model: Albedo Feedback, Stable States and Hysteresis

We investigate the effect of radiative feedbacks on the Arctic Ocean's ice cover. The shortwave radiative feedback is driven by surface albedo differences between sea ice and ocean. The longwave feedback is driven by surface/air temperature fluctuations. These two effects are studied through a coupled cell model that allows for a phase transition. Published solutions to one-dimensional models of the arctic's sea ice-ocean system exhibit two stable states: (i) perennial ice cover, or (ii) no ice cover at all. Our two-dimensional coupled cell model approach supports these results. The model exhibits ice-albedo feedback in the transition from the ice-covered stable state to the open water stable state. Furthermore, we can show that considerable cooling of the model domain is necessary to return from the open water stable state to the ice-covered stable state (hysteresis). The amount of hysteresis is driven by the difference in surface albedo between ice and open ocean.