New oceanographic data from beneath Ronne Ice Shelf, Antarctica

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.

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