Changes in Internal Wave‐Driven Mixing Across the Arctic Ocean: Finescale Estimates From an 18‐Year Pan‐Arctic Record

Abstract

Abstract The Arctic climate is changing rapidly, with dramatic sea ice declines and increasing upper‐ocean heat content. While oceanic heat has historically been isolated from the sea ice by weak vertical mixing, it has been hypothesized that a reduced ice pack will increase energy transfer from the wind into the internal wave (IW) field, enhancing mixing and accelerating ice melt. We evaluate this positive ice/internal‐wave feedback using a finescale parameterization to estimate dissipation, a proxy for the energy available for IW‐driven mixing, from pan‐Arctic hydrographic profiles over 18 years. We find that dissipation has nearly doubled in summer in some regions. Associated heat fluxes have risen by an order of magnitude, underpinned by increases in the strength and prevalence of IW‐driven mixing. While the impact of the ice/internal‐wave feedback will likely remain negligible in the western Arctic, sea‐ice melt in the eastern Arctic appears vulnerable to the feedback strengthening.