Ice Shelf Cavity Estuarine Hydrodynamics at the Kamb Ice Stream Grounding Line

Abstract:

We report on oceanographic data from a recent field season at the Kamb Ice Stream grounding line (82°S 47.0464' 155°W 15.7601') a region of arrested ice flow into the eastern margin of the Ross Ice Shelf. The field site, around 5 km offshore from the grounding line, was focused around a hot water borehole to access the ~30 m thick ocean cavity. We measured the water column structure of the ocean cavity at KIS1/HWD1 over a week-long period that spanned from spring tides to neap tides. The observations captured salinity, temperature and turbidity structure using various precision ocean instruments. Over the spring-neap period the stratification shifts from one where the overarching central quasi-stratification has gradient regions to a simple two-layer structure - and then back again. Some ephemera are also observed like occasional near-surface layers both under the ice and at the bed as well as some internal instability. In addition, we describe the first several months of timeseries data from an on-going hydrographic mooring deployed to report ocean currents and temperature and salinity. The tidal currents appear to be stronger than model estimates and there is a clear estuarine residual flow.