Bed topography and stickiness inferred from surface measurements on ice streams

Ůr÷stur Ůorsteinsson*, R. Bindschadler||, G. H. Gu­mundsson# and C. F. Raymond*
* Geophysics Program, University of Washington, Seattle, WA 98195, USA
|| NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
# VAW-ETH Zentrum, Gloriastrasse 37/39, CH-8092, Zurich, Switzerland

 

We invert for bed topography, B and stickiness C, which are related to surface topography, S, and velocities, U and V, through transfer-functions, T:

S = TSB B + TSC C
U = TUB B + TUC C
V = TVB B + TVC C

Assumptions and Geometry
  • Internal deformation much smaller than sliding
  • Linear Viscous Fluid Behavior of the Ice
  • Bed topography and stickiness variations treated as perturbations
 
Conclusions
  • Structures down to ~0.5 km wavelength can be detected
  • Good surface data (elevation and horizontal velocities), at ~0.25 km spacing, is the key for successful inversion.

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