Basal melt of the southern Filchner Ice Shelf, Antarctica

Abstract

Basal melt of ice shelves is a key factor governing discharge of ice from the Antarctic Ice Sheet as a result of its effects on buttressing. Here, we use radio echo sounding to determine the spatial variability of the basal melt rate of the southern Filchner Ice Shelf, Antarctica, along the inflow of Support Force Glacier. We find moderate melt rates with a maximum of 1.13 ma-1 about 50km downstream of the grounding line. The variability of the melt rates over distances of a few kilometres is low (all but one <0.15ma-1 at <2km distance), indicating that measurements on coarse observational grids are able to yield a representative melt rate distribution. A comparison with remote-sensing-based melt rates revealed that, for the study area, large differences were due to inaccuracies in the estimation of vertical strain rates from remote sensing velocity fields. These inaccuracies can be overcome by using modern velocity fields.