Modeling Tidal Current Profiles and Vertical Mixing beneath Filchner–Ronne Ice Shelf, Antarctica

Abstract

Abstract One of the warmest water masses beneath Filchner–Ronne Ice Shelf (FRIS) is dense, high salinity shelf water (HSSW) that flows into the sub-ice-shelf cavity from the ice front and occupies the lower portion of the water column. A one-dimensional turbulence closure ocean model has been applied to this high latitude sub-ice-shelf environment to demonstrate that tidal currents mix HSSW vertically through the water column and cause melting at the bottom of the ice shelf. Significantly FRIS lies near the critical latitude for the semidiurnal tide, where the Coriolis frequency equals the tidal frequency, resulting in a strongly depth-dependent tidal current and thick boundary layers. Using the model, the effect of the critical latitude, stratification, and the polarization of the tidal current ellipse on boundary layer structure and subsequent vertical mixing are examined. The model shows that stratification significantly affects how the shape of the tidal current ellipse varies with depth and that both...