HR: 1340h
AN: C23A-0980    [Abstracts]
TI: Rheology of the Ronne Ice Shelf, Antarctica, inferred from satellite radar interferometry data using an inverse control method.
AU: * larour, e y
EM: eric.larour@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: rignot, e
EM: eric.rignot@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: joughin, I
EM: ian.joughin@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AB: Ice shelves floating around the Antarctic Ice Sheet spread under their own weight into the ocean. The ice flow is controlled by the rigidity of ice, and a delicate interaction with bottom and surface accumulation. Rigidity ( or flow law parameter $B$ ) depends mainly on temperature [{\em Paterson, 1994}], and fabrics. This study presents an inverse control method developped to infer $B$ on ice shelves. The method is based on finding the best fit with observations of ice velocity from satellite radar interferometry. The model was tested on the Ronne Ice Shelf, and the results show flow law parameter $B$ varying between 300 kPa a$^{1/3}$ and 900 kPa a$^{1/3}$. Minimums appear along the ice margins which could be due to ice softening (viscous heating). High values are found in the wake of large glaciers which advect large quantities of cold ice. Some areas near the grounding lines experience basal melting, which increases rigidity. Melting near the icefront corresponds to areas of decreased rigidity. This method allows the modeller to account for variations in the distribution of $B$ in ice flow models. We thank the California Institude of Technology for making this study possible.
DE: 5104 Fracture and flow
DE: 6924 Interferometry
DE: 2753 Numerical modeling
DE: 3260 Inverse theory
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting