Energetics of the Upper‐Ocean Under Sea Ice: Frictional Dissipation Versus Baroclinic Production

Abstract In polar regions, the presence of sea ice is known to reduce the ocean's eddy kinetic energy (EKE) by enhancing frictional dissipation at the surface. Here, using a coupled ocean—sea ice model, we discuss a mechanism that can instead increase EKE generation under sea ice and, in our simulations, compensates surface dissipation by 69% to 30% for sea ice concentrations varying between 30% and 100%. Mesoscale Ekman pumping and suction due to the sea ice cover give rise to vertical buoyancy fluxes in the core of mesoscale eddies, leading to rectified baroclinic energy production below the mixed layer. Additionally, in the shallow surface layer (5 m), heterogeneous sea ice melt generates mixed layer eddies that enhance baroclinic production for conditions typical of the summer marginal ice zone (MIZ). EKE dissipation and production are both affected by the dynamics of the individual ice floes resolved in our model, which result in distinct patterns of sea ice aggregation around ocean eddies, a preference for anticyclonic floe rotation in the MIZ, and size‐dependent melt. These results emphasize the tightly coupled nature of ocean—sea ice interactions, and the challenge in capturing them within coarse and continuum‐based models.