The Impact of Fronts and Eddies Under Various Melt Conditions on Antarctic Ice Shelves

Abstract Ocean eddies are observed beneath Antarctic ice shelves, yet their role in regulating basal melting remains unclear. We use nonhydrostatic Large‐Eddy Simulations that resolve eddies and boundary‐layer turbulence to examine a baroclinically unstable salinity front that breaks into eddies. Anticyclones reorganize the density field by transporting freshwater across the front and forming subsurface isopycnal troughs, which drive upwelling within eddy cores. This vertical circulation transports warmer subsurface water toward the ice base, enhancing peak melting rates by up to double depending on the vertical thermal structure of the eddy. In contrast, cyclones produce downwelling that suppresses melting. Ekman dynamics and buoyancy‐driven density adjustment regulate the vertical circulation. The turbulence‐resolving nonhydrostatic simulations additionally capture diffusive convection that develops in warmer cavity environments, providing an additional pathway for vertical heat transport close to the ice. Simulated ocean properties and melt rates agree with recent Antarctic observations of eddy‐driven upwelling beneath ice shelves.