Oceanographic conditions south of Berkner Island, beneath Filchner-Ronne Ice Shelf, Antarctica
Article first published online: 20 SEP 2012
Copyright 2001 by the American Geophysical Union.
Journal of Geophysical Research: Oceans (1978–2012)
Volume 106, Issue C6, pages 11481–11492, 15 June 2001
How to Cite
2001), Oceanographic conditions south of Berkner Island, beneath Filchner-Ronne Ice Shelf, Antarctica, J. Geophys. Res., 106(C6), 11481–11492, doi:10.1029/2000JC000350., , , and (
- Issue published online: 20 SEP 2012
- Article first published online: 20 SEP 2012
- Manuscript Accepted: 23 JAN 2001
- Manuscript Received: 4 APR 2000
We have made oceanographic measurements at two sites beneath the southern Filchner-Ronne Ice Shelf. Hot-water drilled access holes were made during January 1999, allowing conductivity-temperature-depth (CTD) profiling and the deployment of instrument moorings. The CTD profiles show that the entire water column is below the surface freezing point. We estimate the (summer) flux of water between the two sites to be 2×106 m3 s−1. The summer potential temperature-salinity properties of the water column suggest that this flow is part of a recirculation in the deepest part of the subice shelf cavity and the Filchner Depression. The recirculation is driven by a combination of the melting of deep basal ice and the freezing that results from the depressurization of the cold buoyant water as it ascends the ice shelf base. The source of the water was high-salinity shelf water (HSSW) produced in the Ronne Depression. This is the water that provides the external heat necessary for the strong melting at the deep grounding lines in the vicinity of Foundation Ice Stream. Instruments moored at the drill sites show that during the winter HSSW formed on the Berkner Shelf flows beneath the ice shelf and largely displaces the recirculating water from the two sites. This provides an externally driven through flow that is warmer (nearer the surface freezing point) and slower than the internal recirculation and which is low enough in density to escape the Filchner Depression.