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

J.A. Åström, D.I. Benn

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)
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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.
Original languageEnglish
JournalGeophysical Research Letters
VolumeEarly View
Early online date20 Nov 2019
DOIs
Publication statusE-pub ahead of print - 20 Nov 2019

Keywords

  • Ice shelves
  • Sea ice
  • Modelling

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