Quantifying the interplay of sea ice meltwater and ice–albedo feedbacks in the Arctic ice-ocean system

Abstract. Sea ice melting generates multiple feedbacks through the release of sea-ice meltwater (SIMW) and the expansion of open water. Due to the tight coupling of the ice-ocean system, these feedbacks are challenging to quantify independently. We employ a one-dimensional coupled sea ice-ocean model, by removing SIMW or keeping sea ice constant during the melting season, to quantify the independent effects of SIMW and ice-albedo feedbacks on the Arctic ice-ocean system. The experiments reveal the following: (1) The strong stratification induced by SIMW traps a portion of solar radiation, forming the Near-Surface Temperature Maximum (NSTM) and generating negative feedback that reduces summer ice melting by 19 % (feedback factor γ= −0.19). (2) The ice-albedo positive feedback amplifies summer ice melting by 41 % (γ= +0.41). (3) These two feedbacks exhibit nonlinear interdependence: disabling the ice-albedo feedback reduces the SIMW feedback strength to −0.09, while eliminating SIMW effects enhances the ice-albedo feedback to +0.46. The impact of summer melting extends into the freezing season: intensified summer ice melt enhances early winter ice formation in strongly stratified regions, as reduced ice thickness and expanded open water areas in early winter accelerate oceanic heat loss, thereby promoting rapid freezing. Conversely, in the weakly stratified western Nansen Basin, summer SIMW release plays a critical role in preventing the upward mixing of Atlantic Warm Water, thereby protecting the winter ice cover. The SIMW influences are more pronounced under thinner initial sea ice, indicating that as Arctic sea ice continues to decline and Atlantification intensifies, the role of SIMW in regulating the Arctic ice-ocean system is expected to become increasingly significant.