Quantifying the interplay of Meltwater and Ice-Albedo Feedbacks in the Arctic Ice-Ocean System

Sea ice melting generates multiple feedbacks through meltwater release and open water expansion. Due to the tight coupling of the ice-ocean system, these feedbacks are challenging to quantify independently. We employ a well-validated one-dimensional coupled sea ice-ocean model, by removing meltwater or keeping sea ice constant during the melting season, to quantify the independent effects of meltwater and ice-albedo feedbacks on the Arctic ice-ocean system. The experiments reveal the following: (1) Meltwater-induced strong stratification can insulate a portion of solar radiation into the Near Surface Temperature Maximum (NSTM), generating a negative feedback with a feedback factor of -0.19 (i.e., 19 % ice melting reduction). (2) The ice-albedo positive feedback factor is +0.41 (i.e., 41 % ice melting amplification). (3) These two feedback processes exhibit nonlinear interdependence: switching off the ice-albedo feedback reduces the meltwater feedback strength to -0.09, while eliminating meltwater effects enhances the ice-albedo feedback to +0.46. Meltwater effects persist until the following freezing season. The NSTM insulated by meltwater in summer suppresses ice formation during winter in strongly stratified regions. In the weakly stratified western Nansen Basin, summer meltwater release plays an important role in preventing the upward mixing of Atlantic warm water. The meltwater feedback in the ice-ocean system is more pronounced in experiments with thinner initial sea ice, indicating that as Arctic sea ice will continue to decline and Atlantification will intensify in the future, the impact of meltwater on the ice-ocean system is expected to become increasingly significant.