Campus Units

Geological and Atmospheric Sciences

Document Type

Article

Publication Version

Published Version

Publication Date

2-16-2020

Journal or Book Title

Geophysical Research Letters

Volume

47

Issue

3

First Page

e2019GL084924

DOI

10.1029/2019GL084924

Abstract

Results of glacier flow models and associated estimates of future sea level rise depend sensitively on the prescribed relation between shear stress and slip velocity at the glacier bed. Using a fully three‐dimensional numerical model of ice flow, we compute steady‐state sliding relations for where ice slips over a rock bed with three‐dimensional, periodic topography. In agreement with studies of two‐dimensional beds, water‐filled cavities that form down‐glacier from bedforms cause basal shear stress to peak at a threshold slip velocity and decrease at higher velocities (i.e., rate‐weakening drag). However, the shear stress magnitude and extent of rate‐weakening drag depend systematically on lateral topographic variations not considered previously. Moreover, steep up‐glacier‐facing slopes of bedforms can result in shear stress that increases monotonically over a wide range of slip velocity, helping to stabilize slip. These results highlight the potential variability of sliding relations and their likely sensitivity to the morphological diversity of glacier beds.

Comments

This article is published as Helanow, Christian, Neal R. Iverson, Lucas K. Zoet, and Olivier Gagliardini. "Sliding Relations for Glacier Slip With Cavities Over Three‐Dimensional Beds." Geophysical Research Letters 47, no. 3 (2020): e2019GL084924. doi: 10.1029/2019GL084924. Posted with permission.

Copyright Owner

American Geophysical Union

Language

en

File Format

application/pdf

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