Sensitivity of a calving glacier to ice—ocean interactions under climate change : new insights from a 3-D full-Stokes model
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Iceberg calving accounts for between 30 % and 60 % of net mass loss from the Greenland Ice Sheet, which has intensified and is now the single largest contributor to global sea level rise in the cryosphere. Changes to calving rates and the dynamics of calving glaciers represent a significant uncertainty in projections of future sea level rise. A growing body of observational evidence suggests that calving glaciers respond rapidly to regional environmental change, but predictive capacity is limited by the lack of suitable models capable of simulating calving mechanisms realistically. Here, we use a 3-D full-Stokes calving model to investigate the environmental sensitivity of Store Glacier, a large outlet glacier in West Greenland. We focus on two environmental processes: undercutting by submarine melting and buttressing by ice mélange, and our results indicate that Store Glacier is likely to be able to withstand moderate warming perturbations in which the former is increased by 50 % and the latter reduced by 50 %. However, severe perturbation with a doubling of submarine melt rates or a complete loss of ice mélange destabilises the calving front in our model runs. Furthermore, our analysis reveals that stress and fracture patterns at Store's terminus are complex and varied, primarily due to the influence of basal topography. Calving style and environmental sensitivity vary greatly, with propagation of surface crevasses significantly influencing iceberg production in the northern side, whereas basal crevasses dominate in the south. Any future retreat is likely to be initiated in the southern side by a combination of increased submarine melt rates in summer and reduced mélange strength in winter. The lateral variability, as well as the importance of rotational and bending forces at the terminus, underlines the importance of using the 3-D full-Stokes stress solution when modelling Greenland's calving glaciers.
Todd , J , Christoffersen , P , Zwinger , T , Råback , P & Benn , D I 2019 , ' Sensitivity of a calving glacier to ice—ocean interactions under climate change : new insights from a 3-D full-Stokes model ' , The Cryosphere , vol. 13 , no. 6 , pp. 1681-1694 . https://doi.org/10.5194/tc-13-1681-2019
Copyright © Author(s) 2019. Published by Copernicus Publications on behalf of the European Geosciences Union. This work is distributed under the Creative Commons Attribution 4.0 License.
DescriptionThis study was funded by the Natural Environment Research Council through a PhD studentship to Joe Todd (grant no. NE/K500884/1) and a research grant (NE/K005871/1) to Poul Christoffersen. Poul Christoffersen also acknowledges support from the European Research Council under the European Union’s Horizon 2020 Research and Innovation programme (grant agreement 683043). We acknowledge that the results of this research have been achieved using the PRACE- 3IP project DynaMITE (FP7 RI-312763) awarded to Joe Todd and Poul Christoffersen with the resource Sisu based in Finland at CSC.
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