Satellite observations reveal the impact of changing sea ice on wintertime surface turbulent fluxes over the Arctic Ocean

Sea ice-driven turbulent fluxes are critical for Arctic warming and ocean mixing. However, the influence of evolving sea ice surface properties and types on Arctic-wide ice/sea‒air turbulent exchanges remain poorly understood. This study estimates wintertime surface turbulent fluxes across the Arctic Ocean during 2002−2020, integrating various satellite-based sea ice observations with atmospheric reanalysis. Our results reveal a weakening momentum flux in the central Arctic (−0.007 N/m 2 per decade), closely associated with reduced surface roughness caused by the loss and smoothing of multi-year ice. Meanwhile, the retreat of first-year ice (FYI) and expansion of the marginal ice zone (MIZ) have increased upward sensible and latent heat fluxes in the Barents-Kara Sea (+3.2 W/m 2 per decade) and +6.3 W/m 2 per decade, respectively). Within the ice-covered regions, FYI has become the dominant driver of air‒ice momentum exchange, while the contributions of polynyas and MIZ to sensible heat release have risen by 2% per decade and 4% per decade, respectively. Overall, thinner and more dynamic ice types like FYI and regions with open water (like polynyas and MIZ) are becoming more important for momentum and heat exchange in the Arctic.