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The Cryosphere An interactive open-access journal of the European Geosciences Union
doi:10.5194/tc-2017-8
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
30 Jan 2017
Review status
This discussion paper is under review for the journal The Cryosphere (TC).
Sea-level response to melting of Antarctic ice shelves on multi-centennial time scales with the fast Elementary Thermomechanical Ice Sheet model (f.ETISh v1.0)
Frank Pattyn Laboratoire de Glaciologie, Department of Geosciences, Environment and Society, Université libre de Bruxelles, Av. F.D. Roosevelt 50, B–1050 Brussels, Belgium
Abstract. The magnitude of the Antarctic ice sheet's contribution to global sea-level rise is dominated by the potential of its marine sectors to become unstable and collapse as a response to ocean (and atmospheric) forcing. This paper presents Antarctic sea-level response to sudden atmospheric and oceanic forcings on multi-centennial time scales with the newly developed fast Elementary Thermomechanical Ice Sheet (f.ETISh) model. The f.ETISh model is a vertically integrated hybrid ice sheet/ice shelf model with an approximate implementation of ice sheet thermomechanics, making the model two-dimensional. Its marine boundary is represented by two different flux conditions, coherent with power-law basal sliding and Coulomb basal friction. The model has been compared to a series of existing benchmarks.

Modelled Antarctic ice sheet response to forcing is dominated by sub-ice shelf melt and the sensitivity is highly dependent on basal conditions at the grounding line. Coulomb friction in the grounding-line transition zone leads to significantly higher mass loss in both West and East Antarctica on centennial time scales, leading to 2 m sea level rise after 500 years for a moderate melt scenario of 20 m a−1 under freely-floating ice shelves, up to 6 m for a 50 m a−1 scenario. The higher sensitivity is attributed to higher driving stresses upstream from the grounding line.

Removing the ice shelves altogether results in a disintegration of the West Antarctic ice sheet and (partially) marine basins in East Antarctica. After 500 years, this leads to a 4.5 m and a 12.2 m sea level rise for the power-law basal sliding and Coulomb friction conditions at the grounding line, respectively. The latter value agrees with simulations by DeConto and Pollard (2016) over a similar period (but with different forcing and including processes of hydro-fracturing and cliff failure).

The chosen parametrizations make model results largely independent of spatial resolution, so that f.ETISh can potentially be integrated in large-scale Earth system models.


Citation: Pattyn, F.: Sea-level response to melting of Antarctic ice shelves on multi-centennial time scales with the fast Elementary Thermomechanical Ice Sheet model (f.ETISh v1.0), The Cryosphere Discuss., doi:10.5194/tc-2017-8, in review, 2017.
Frank Pattyn
Frank Pattyn
Frank Pattyn

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Short summary
Marine Ice Sheet Instability is a mechanism that can potentially lead to collapse of marine sectors of the Antarctic ice sheet and floating ice shelves play a crucial role herein. Improved grounding line physics (interaction with subglacial sediment) that are implemented in a new ice-sheet model results in a sea level rise of more than 12 m after 500 years, making the Antarctic ice sheet particularly vulnerable to ice shelf weakening.
Marine Ice Sheet Instability is a mechanism that can potentially lead to collapse of marine...
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