Ocean mixing beneath Pine Island Glacier ice shelf, West Antarctica

Ice shelves around Antarctica are vulnerable to an increase in ocean-driven melting, with the melt rate depending on ocean temperature and the strength of flow inside the ice-shelfcavities. We present measurements of velocity, temperature, salinity, turbulent kinetic energy dissipationrate, and thermal variance dissipationrate beneath Pine Island Glacier ice shelf, West Antarctica. These measurements were obtained by CTD, ADCP, and turbulence sensors mounted on an Autonomous Underwater Vehicle (AUV). The highest turbulent kinetic energy dissipationrate is found near the grounding line. The thermal variance dissipationrate increases closer to the ice-shelfbase, with a maximum value found ∼0.5 m away from the ice. The measurements of turbulent kinetic energy dissipationrate near the ice are used to estimate basal melting of the ice shelf. The dissipation-rate-based melt rate estimates is sensitive to the stability correction parameter in the linear approximationof universal function of the Monin-Obukhov similarity theoryfor stratified boundary layers. We argue that our estimates of basal melting from dissipationrates are within a range of previous estimates of basal melting.