Viscosity and elasticity: A model intercomparison of ice-she

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TitleViscosity and elasticity: A model intercomparison of ice-shelf bending in an Antarctic grounding zoneAbstractGrounding zones are vital to ice-sheet mass balance and its coupling to the global ocean circulation. Processes here determine the mass discharge from the grounded ice sheet, to the floating ice shelves. The response of this transition zone to tidal forcing has been described by both elastic and viscoelastic models. Here we examine the validity of these models for grounding zone flexure over tidal timescales using field data from the Southern McMurdo Ice Shelf (78° 15′S, 167° 7′E). Observations of tidal movement were carried out by simultaneous tiltmeter and GPS measurements along a profile across the grounding zone. Finite-element simulations covering a 64 d period reveal that the viscoelastic model fits best the observations using a Young's modulus of 1.6 GPa and a viscosity of 1013.7 Pa s (≈ 50.1 TPa s). We conclude that the elastic model is only well-constrained for tidal displacements >35% of the spring-tidal amplitude using a Young's modulus of 1.62 ± 0.69 GPa, but that a viscoelastic model is necessary to adequately capture tidal bending at amplitudes below this threshold. In grounding zones where bending stresses are greater than at the Southern McMurdo Ice Shelf or ice viscosity is lower, the threshold would be even higher. © The Author(s) 2017.

Details

1st AuthorWild, C. AuthorWild, C.Marsh, O.Rack, W.Year2017JournalJournal of GlaciologyVolume63Number240Pages573-580DOI10.1017/jog.2017.15URLhttps://www.scopus.com/inward/recor.....ebc3d7feb67e6888f15aa6bc2PublisherCambridge University PressKeywordsair-sea interactionbendingelasticityglaciologyGPSice mechanicsice shelfremote sensingviscosityYoung modulus, AntarcticaEast AntarcticaMcMurdo Ice ShelfAuthor Keywordsglaciological model experimentsice rheologyice shelvesice/ocean interactionsremote sensing

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CitationWild, C., Marsh, O. and Rack, W. (2017). Viscosity and elasticity: A model intercomparison of ice-shelf bending in an Antarctic grounding zone. Journal of Glaciology, 63(240): 573-580Antarctica NZ supported?YesNZARI?Yes

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