Antarctic Science

PHYSICAL SCIENCES

New ice thickness maps of Filchner–Ronne Ice Shelf, Antarctica, with specific focus on grounding lines and marine ice

A. Lambrechta1a2, H. Sandhägera1, D.G. Vaughana3 and C. Mayera4

a1 Stiftung Alfred Wegener Institut für Polar- und Meeresforschung, Postfach 120161, 27515 Bremerhaven, Germany

a2 now at: Institute of Meteorology and Geophysics, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria

a3 British Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge CB3 0ET, UK

a4 Commission for Glaciology, Bavarian Academy of Sciences and Humanities, Alfons-Goppel Str. 11, 80539 Munich, Germany astrid.lambrecht@uibk.ac.at

Abstract

For the Filchner–Ronne Ice Shelf we have compiled measurements of meteoric ice thickness from many institutions, and several different techniques (e.g. radar and seismic sounding) to produce an improved digital map of meteoric ice thickness. This map has high-resolution compared to previous compilations and serves to highlight small-scale geographic features (e.g. ice plains, grounding-line regions). We have also produced a map of the thickness of marine ice bodies beneath the ice shelf by using borehole density data to calibrate an ice thickness to surface-elevation relation, and then comparing maps of ice surface elevation and meteoric ice thickness to infer marine ice thickness. Due to denser data coverage and the improved density-depth relation, the resulting map is a significant improvement on its predecessors and allows insight into the glaciological context of the ice shelf, in particular, into the location of the grounding lines on the southern Ronne Ice Shelf. Here the data were supplemented with barometric determination of surface elevation, which were used to locate the grounding line position. The final delineation of the grounding line position was confirmed by reference to satellite imagery, and revealed that earlier estimates were substantially in error, especially in the area of Foundation Ice Stream and Möllereisstrom.

(Received October 25 2006)

(Accepted May 03 2007)

(Online publication September 06 2007)

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