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The internal deformation regime of Thwaites Glacier

conference contribution
posted on 2023-05-24, 19:18 authored by Felicity McCormack, Roland WarnerRoland Warner, Adam TreverrowAdam Treverrow, Seroussi, H
Internal deformation is the main process controlling ice flow in ice shelves and in slow-moving regions of polar ice sheets where the ice is frozen to the bed. However, the contribution of internal deformation to flow in ice streams and fast-flowing regions is typically poorly constrained in ice sheet models. The current standard description of internal deformation used in most large-scale ice sheet models -- the Glen flow relation -- is limited by its failure to capture the tertiary flow of anisotropic ice that prevails in polar ice sheets. Here, we compare the flow regime of Thwaites Glacier as simulated by the Glen flow relation with a recent flow relation for anisotropic ice -- the ESTAR flow relation. With ESTAR, internal deformation contributes a factor of three times more to overall flow in the Thwaites Glacier ice streaming zone than when using the Glen flow relation. Using temperature dependent flow rate parameters with a stronger physical basis along with the ESTAR flow relation together provide the best match to observed surface velocities, but parameter selection and “matching” (i.e. via inversion) can significantly alter the predicted flow regime. Our results have implications for ice sheet evolution and stability, and may provide insight into an improved picture of basal sliding parameterizations.


Publication title

Abstracts from the Twenty-Sixth Annual WAIS Workshop


Institute for Marine and Antarctic Studies

Event title

Twenty-Sixth Annual WAIS Workshop

Event Venue

Julian, California, U.S.A.

Date of Event (Start Date)


Date of Event (End Date)


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Socio-economic Objectives

Expanding knowledge in the earth sciences

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