New oceanographic data from beneath Ronne Ice Shelf, Antarctica

Abstract

Oceanographic data have been obtained via an access hole made through Ronne Ice Shelf. The site, which is the third in a series of similar studies, lies 17 km west of Korff Ice Rise where 825 m of ice overlies a 485‐m deep water column. Measurements included conductivity and temperature profiles, and an instrument mooring was deployed for long‐term measurements of currents, temperature and conductivity. At the sea floor there was a 150‐m layer of well‐mixed water with a potential temperature and salinity of −1.97°C and 34.72. The water cooled and freshened towards the ice‐shelf base, ultimately reaching −2.41°C and 34.51. The hydrographic and water current data imply a flow into the deepest part of the sub‐ice shelf cavity of about 200,000 m³ s−1 of the deeper, relatively warm water, which would be able to power an average basal melt rate of 0.2 m a−1 for the western portion of Ronne Ice Shelf.