Radar observations of physical processes at the base of the Filchner-Ronne Ice Shelf

Abstract:

Observations of sub-ice shelf environments are scarce and difficult to obtain, yet important for understanding of the role the ocean plays in modulating ice sheet flow. Long-term, high-frequency measurements of basal melt rate have become possible with the recent development of a phase-sensitive radar (ApRES), capable of sampling autonomously for long periods of time. When disentangled from the ice dynamical contributions to thickness change, ApRES observations of basal melt rate carry information about oceanic processes in the ice shelf cavity.
Of many ApRES installations on Antarctic ice shelves, several long term monitoring sites have been set up across the Filchner-Ronne Ice Shelf, sampling various regimes that this large, thick, and complex ice shelf experiences.
Different physical processes in the ice shelf cavity have been inferred from the ApRES data, including the signature of eddies, tidal mixing, intermittent freezing episodes, and inter-annual changes in high salinity shelf water inflow.
Here we will discuss how these processes are represented in the ApRES data and how they vary across the ice shelf.