HR: 13:45h
AN: C43B-02    [Abstracts]
TI: Observational Constraints on Ice Shelf Mechanics from GLAS
AU: Fricker, H A
EM: hafricker@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, San Diego, CA 92093-0225 United States
AU: Bassis, J
EM: jbassis@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, San Diego, CA 92093-0225 United States
AU: * Minster, J
EM: jbminster@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, San Diego, CA 92093-0225 United States
AB: The Geoscience Laser Altimeter System (GLAS) on the ICESat satellite is the first spaceborne laser altimeter to acquire data over Antarctica's ice shelves. The small (65m) footprint of GLAS enables it to sample the ice shelves with horizontal resolution heretofore unattainable with radar altimeters. This capability, combined with its high vertical accuracy, makes it a powerful tool for studying ice shelf features. We use GLAS surface elevation profiles of ice shelf rifts to constrain mechanical models of the rifting process. The GLAS profiles reveal vertical structure on either side of the rift, as well as within the rift-filling "m‚lange." Repeat GLAS profiles provide us with information on the time dependence of these structures. We find evidence of a deformation zone that extends for several ice thicknesses on either side of the rift, and interpret this in terms of a plastic necking instability that amplifies small initial perturbations in the structure of the ice shelf. The GLAS data also reveal topographic profiles across the ice shelf fronts that are consistence with hydrostatic forces acting at the ice front.
DE: 9310 Antarctica
SC: Cryosphere [C]
MN: 2005 Joint Assembly