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Modeling the deformation regime of Thwaites Glacier, West Antarctica, using a simple flow relation for ice anisotropy (ESTAR)
Citation
McCormack, FS and Warner, RC and Seroussi, H and Dow, CF and Roberts, JL and Treverrow, A, Modeling the deformation regime of Thwaites Glacier, West Antarctica, using a simple flow relation for ice anisotropy (ESTAR), Journal of Geophysical Research-Earth Surface, 127, (3) Article e2021JF006332. ISSN 2169-9003 (2022) [Refereed Article]
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© 2022. The Authors. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) License (https://creativecommons.org/licenses/by-nc-nd/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed.
Abstract
Ice deformation dominates the evolution of ice shelf flow and the slow-moving regions in the
interior of ice sheets. However, deformation may be poorly represented in large-scale ice sheet models that
use the Glen flow relation, due to its questionable applicability to the steady-state flow of anisotropic ice
that prevails in ice sheets, having been derived from secondary creep rates of isotropic ice. We assess the
deformation regimes of Thwaites Glacier, West Antarctica, using the Glen and "Empirical Scalar Tertiary
Anisotropy Regime", (ESTAR) flow relations, the latter being derived from steady-state deformation rates of
anisotropic ice. For grounded ice, the character of the flow relation determines the contribution of deformation
to overall flow, with ESTAR producing greater bed-parallel shear deformation than the standard Glen flow
relation. The ESTAR experiments show larger basal shear stress maxima than the standard Glen experiment
because ESTAR treats the responses to simple shear stresses and compression stresses differently, reducing
the role of lateral and longitudinal stresses in momentum balance. On the Thwaites Glacier Tongue, ESTAR
provides the best match to observed speeds by accounting for the differing effects of stresses on ice flow. Our
results highlight the importance of the numerical description of anisotropy, particularly: In regions of transition
from deformation-dominated to sliding-dominated flow; in the approach to the grounding line, and across
ice shelves. Given the importance of these locations in determining mass flux into the ocean, our results have
implications for projections of sea level change from Antarctic ice loss.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | ice deformation, ice sheets, glacial ice |
| Research Division: | Earth Sciences |
| Research Group: | Physical geography and environmental geoscience |
| Research Field: | Glaciology |
| Objective Division: | Environmental Management |
| Objective Group: | Management of Antarctic and Southern Ocean environments |
| Objective Field: | Antarctic and Southern Ocean ice dynamics |
| UTAS Author: | McCormack, FS (Dr Felicity McCormack) |
| UTAS Author: | Warner, RC (Dr Roland Warner) |
| ID Code: | 154118 |
| Year Published: | 2022 |
| Web of Science® Times Cited: | 1 |
| Deposited By: | Australian Antarctic Program Partnership |
| Deposited On: | 2022-10-31 |
| Last Modified: | 2022-11-30 |
| Downloads: | 5 View Download Statistics |
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