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Mapping the grounding zone of the Amery Ice Shelf, East Antarctica using InSAR, MODIS and ICESat

Published online by Cambridge University Press:  01 October 2009

Helen Amanda Fricker*
Affiliation:
Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0225, USA
Richard Coleman
Affiliation:
Centre for Marine Science, University of Tasmania, Private Bag 115, Hobart, TAS 7001, Australia Antarctic Climate and Ecosystems CRC, Hobart, Australia CSIRO Marine and Atmospheric Research, Hobart, Australia
Laurie Padman
Affiliation:
Earth & Space Research, 3350 SW Cascade Ave, Corvallis, OR 97333-1536, USA
Ted A. Scambos
Affiliation:
National Snow and Ice Data Center, CIRES, Campus Box 449, 1540 30th St, University of Colorado, Boulder, CO 80309-0449, USA
Jennifer Bohlander
Affiliation:
National Snow and Ice Data Center, CIRES, Campus Box 449, 1540 30th St, University of Colorado, Boulder, CO 80309-0449, USA
Kelly M. Brunt
Affiliation:
Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0225, USA

Abstract

We use a combination of satellite techniques (interferometric synthetic aperture radar (InSAR), visible-band imagery, and repeat-track laser altimetry) to develop a benchmark map for the Amery Ice Shelf (AIS) grounding zone (GZ), including its islands and ice rises. The break-in-slope, as an indirect estimate of grounding line location, was mapped for the entire AIS. We have also mapped ∼55% of the landward edge and ∼30% of the seaward edge of the ice shelf flexure boundary for the AIS perimeter. Vertical ice motion from Global Positioning System receivers confirms the location of the satellite-derived GZ in two regions. Our map redefines the extent of floating ice in the south-western AIS and identifies several previously unmapped grounded regions, improving our understanding of the stresses supporting the current dynamical state of the ice shelf. Finally, we identify three along-flow channels in the ice shelf basal topography, approximately 10 km apart, 1.5 km wide and 300–500 m deep, near the southern GZ. These channels, which form at the suture zones between ice streams, may represent zones of potential weakness in the ice shelf and may influence sub-ice-shelf ocean circulation.

Type
Physical Sciences
Copyright
Copyright © Antarctic Science Ltd 2009

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