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GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L21504, doi:10.1029/2007GL031483, 2007

Radar-derived bed roughness characterization of Institute and Möller ice streams, West Antarctica, and comparison with Siple Coast ice streams

Robert G. Bingham

British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
Centre for Polar Observation and Modelling, Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, UK


Martin J. Siegert

Centre for Polar Observation and Modelling, School of GeoSciences, University of Edinburgh, Edinburgh, UK


Abstract

Subglacial bed conditions exert a significant control on ice stream behavior and evolution, and can be characterized by determining bed roughness from FFT analysis of radar-imaged basal reflectors. Here we assess bed roughness across Institute and Möller ice streams, West Antarctica, and compare our findings with bed roughness determined across the Siple Coast ice streams. We find that variations in bed roughness are spatially organized, and attribute this to the varying efficacy of subglacial erosion and deposition, with rougher (inland, slow-flowing) regions largely manifesting preglacial topography, and smoother (downstream, fast-flowing) regions evincing significant postglacial modification to the subglacial landscape. The observed similarities between bed roughness characteristics of IIS/MIS and the Siple ice streams suggest that IIS and MIS are largely underlain by wet, poorly consolidated sediments, and may therefore be vulnerable to the types of dynamical instabilities experienced by the Siple ice streams.

Received 26 July 2007; accepted 5 October 2007; published 8 November 2007.

Keywords: bed roughness; West Antarctica; airborne radar.

Index Terms: 0730 Cryosphere: Ice streams; 0726 Cryosphere: Ice sheets; 0758 Cryosphere: Remote sensing; 0774 Cryosphere: Dynamics; 0776 Cryosphere: Glaciology (1621, 1827, 1863).

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Citation: Bingham, R. G., and M. J. Siegert (2007), Radar-derived bed roughness characterization of Institute and Möller ice streams, West Antarctica, and comparison with Siple Coast ice streams, Geophys. Res. Lett., 34, L21504, doi:10.1029/2007GL031483.