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Effective rheology across the fragmentation transition for sea ice and ice shelves

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Date
20/11/2019
Author
Åström, J.A.
Benn, D.I.
Keywords
Ice shelves
Sea ice
Modelling
G Geography (General)
DAS
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Abstract
Sea ice and ice shelves can be described by a viscoelastic rheology that is approximately linear elastic and brittle at high strain rates, and viscously shear‐thinning at low strain rates. Brittle ice easily fractures under compressive shear and forms shear bands as the material undergoes a transition to a fragmented, granular state. This transition plays a central role in the mechanical behaviour at large scales of sea‐ice in the Arctic Ocean or Antarctic ice shelves. Here we demonstrate that the fragmentation transition is characterized by an essentially discontinuous drop of 3‐5 orders of magnitude in effective viscosity and stress‐relaxation time. Beyond the fragmentation transition, grinding in shear zones further reduces both effective viscosity and shear stiffness, but with an essentially constant relaxation time of ∼10second. These results are relevant for ice‐rheology implementation in large‐scale climate‐related models of sea ice and thin ice shelves.
Citation
Åström , J A & Benn , D I 2019 , ' Effective rheology across the fragmentation transition for sea ice and ice shelves ' , Geophysical Research Letters , vol. Early View . https://doi.org/10.1029/2019GL084896
Publication
Geophysical Research Letters
Status
Peer reviewed
DOI
https://doi.org/10.1029/2019GL084896
ISSN
0094-8276
Type
Journal article
Rights
Copyright © 2019. American Geophysical Union. All Rights Reserved. . This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the final published version of the work, which was originally published at https://doi.org/10.1029/2019GL084896
Description
Funding was provided by the NERC grant NE/P011365/1 Calving Laws for Ice Sheet Models CALISMO. Data files for the plots are found at: https://doi.org/10.5285/76D7D3CA-7B83-4BB0-AAE5-A8E92C7DA5B0
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  • University of St Andrews Research
URI
http://hdl.handle.net/10023/19967

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

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