Subglacial topography and ice volume for western Canadian glaciers from a bed stress model and mass balance fields
Abstract
We describe a method to estimate the thickness of glacier ice using information derived from the measured ice extent, surface topography, and surface mass balance. The approach assumes that ice within individual glacier flowsheds has a well-defined yield stress and that the bottom stress is simply related to the ice thickness and surface slope. The shortcomings of this yield stress approach are well known, among them that when the ice slope is small (as it is near dome-like flow divides) the ice thickness expression becomes singular. A completely different approach to estimate subglacial topography is to assume that thickness varies smoothly and that, between points of known thickness, it can be adequately estimated by simple interpolation. Our objective approach combines the strengths of both methods, is computationally fast, and fully automated. We use our ice-thickness method to estimate the subglacial topography for all glaciers in western Canada that lie south of 60N and from this we estimate the present ice volume for each glacier and the total volume of all glaciers in the region. The total glaciated area ca. AD2005 is 26,728 km2 and we shall present the total ca. AD2005 ice volume and a map of estimated bed topography for the entire study region.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.C33F..04C
- Keywords:
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- 0720 CRYOSPHERE / Glaciers;
- 0762 CRYOSPHERE / Mass balance;
- 0798 CRYOSPHERE / Modeling;
- 1621 GLOBAL CHANGE / Cryospheric change