HR: 0800h
AN: C51A-0084    [Abstracts]
TI: New Antarctic Bedrock and Moho Topography Models from GRACE: Implications for the Cryosphere
AU: * Smith, A E
EM: adrienne@ldeo.columbia.edu
AF: Department of Earth and Environmental Sciences Columbia University, 106 Geoscience Lamont-Doherty Earth Observaory 61 Route 9W, Palisades, NY 10964, United States
AU: Bell, R E
EM: robinb@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964, United States
AU: Studinger, M
EM: mstuding@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964, United States
AU: Velicogna, I
EM: isabella@colorado.edu
AF: Jet Propulsion Laboratory (NASA), 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Velicogna, I
EM: isabella@colorado.edu
AF: CIRES and Dept. of Physics, University of Colorado, Campus Box 390, Boulder, CO 80309, United States
AB: Topography and crustal structure of glaciated continents are critical to the stability and dynamics of the overlying ice sheet but remain difficult to recover on a continental scale. Specifically, the slope and undulation of the underlying bedrock acts as a fundamental control on the flow and stability of the ice sheet. Until recently, large regions of East Antarctica lacked a reasonable topographic model because only scattered observations of ice thickness had been available to constrain the bedrock elevation. The satellite gravity from NASA's Gravity Recovery and Climate Experiment (GRACE) has created a new opportunity to model the sub-ice topography by providing the first geophysical dataset that covers the whole of Antarctica. We have used gravity inversion, a classic geophysical technique, to predict the topographic variation of the bedrock surface. GRACE's free–air anomalies are also sensitive to long wavelength structures including the undulation of the ice sheet surface and the topography on the Moho. We are able to predict Moho topography by removing the gravity effect of BEDMAP as an a priori model, and gain insights into the crustal structure and lithospheric strength. This approach also enables us to map changes in the lithosphere's elastic thickness using a flexural model. Here we present both results from GRACE: new bedrock and mantle topography models for the Antarctic continent. These new continental scale models will enable us to produce new estimates of ice volume and investigate the geodynamic control on ice sheet processes.
DE: 1219 Gravity anomalies and Earth structure (0920, 7205, 7240)
DE: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
SC: Cryosphere [C]
MN: 2007 Fall Meeting