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Modelling the reorientation of sea-ice faults as the wind changes direction

Wilchinsky, Alexander V.; Feltham, Daniel; Hopkins, Mark A.. 2011 Modelling the reorientation of sea-ice faults as the wind changes direction. Annals of Glaciology, 52 (57). 83-90.

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Abstract/Summary

A discrete-element model of sea ice is used to study how a 900 change in wind direction alters the pattern of faults generated through mechanical failure of the ice. The sea-ice domain is 400 km in size and consists of polygonal floes obtained through a Voronoi tessellation. Initially the floes are frozen together through viscous-elastic joints that can break under sufficient compressive, tensile and shear deformation. A constant wind-stress gradient is applied until the initially frozen ice pack is broken into roughly diamond-shaped aggregates, with crack angles determined by wing-crack formation. Then partial refreezing of the cracks delineating the aggregates is modelled through reduction of their length by a particular fraction, the ice pack deformation is neglected and the wind stress is rotated by 90 degrees. New cracks form, delineating aggregates with a different orientation. Our results show the new crack orientation depends on the refrozen fraction of the initial faults: as this fraction increases, the new cracks gradually rotate to the new wind direction, reaching 90 degrees for fully refrozen faults. Such reorientation is determined by a competition between new cracks forming at a preferential angle determined by the wing-crack theory and at old cracks oriented at a less favourable angle but having higher stresses due to shorter contacts across the joints.

Item Type: Publication - Article
Programmes: BAS Programmes > Polar Science for Planet Earth (2009 - ) > Polar Oceans
ISSN: 0260-3055
NORA Subject Terms: Marine Sciences
Glaciology
Date made live: 21 Jun 2011 09:02
URI: http://nora.nerc.ac.uk/id/eprint/14499

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