Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model
<p>Simulations of ice sheet evolution over glacial cycles require integration of observational constraints using ensemble studies with fast ice sheet models. These include physical parameterisations with uncertainties, for example, relating to grounding-line migration. More complete ice dynami...
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Copernicus Publications
2020-11-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/14/3917/2020/tc-14-3917-2020.pdf |
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doaj-85efe26affc54d8494ad34224d637f952020-11-25T04:07:31ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242020-11-01143917393410.5194/tc-14-3917-2020Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes modelC. Schannwell0C. Schannwell1R. Drews2T. A. Ehlers3O. Eisen4O. Eisen5C. Mayer6M. Malinen7E. C. Smith8E. C. Smith9H. Eisermann10Department of Geosciences, University of Tübingen, Tübingen, Germanynow at: Max Planck Institute for Meteorology, Hamburg, GermanyDepartment of Geosciences, University of Tübingen, Tübingen, GermanyDepartment of Geosciences, University of Tübingen, Tübingen, GermanyGlaciology, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, GermanyDepartment of Geosciences, University of Bremen, Bremen, GermanyBavarian Academy of Sciences and Humanities, Munich, GermanyCSC – IT Center for Science Ltd., Espoo, FinlandGlaciology, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germanynow at: School of Earth and Environment, University of Leeds, Leeds, UKGlaciology, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany<p>Simulations of ice sheet evolution over glacial cycles require integration of observational constraints using ensemble studies with fast ice sheet models. These include physical parameterisations with uncertainties, for example, relating to grounding-line migration. More complete ice dynamic models are slow and have thus far only be applied for <span class="inline-formula"><</span> 1000 years, leaving many model parameters unconstrained. Here we apply a 3D thermomechanically coupled full-Stokes ice sheet model to the Ekström Ice Shelf embayment, East Antarctica, over a full glacial cycle (40 000 years). We test the model response to differing ocean bed properties that provide an envelope of potential ocean substrates seawards of today's grounding line. The end-member scenarios include a hard, high-friction ocean bed and a soft, low-friction ocean bed. We find that predicted ice volumes differ by <span class="inline-formula">></span> 50 % under almost equal forcing. Grounding-line positions differ by up to 49 km, show significant hysteresis, and migrate non-steadily in both scenarios with long quiescent phases disrupted by leaps of rapid migration. The simulations quantify the evolution of two different ice sheet geometries (namely thick and slow vs. thin and fast), triggered by the variable grounding-line migration over the differing ocean beds. Our study extends the timescales of 3D full-Stokes by an order of magnitude compared to previous studies with the help of parallelisation. The extended time frame for full-Stokes models is a first step towards better understanding other processes such as erosion and sediment redistribution in the ice shelf cavity impacting the entire catchment geometry.</p>https://tc.copernicus.org/articles/14/3917/2020/tc-14-3917-2020.pdf |
| collection |
DOAJ |
| language |
English |
| format |
Article |
| sources |
DOAJ |
| author |
C. Schannwell C. Schannwell R. Drews T. A. Ehlers O. Eisen O. Eisen C. Mayer M. Malinen E. C. Smith E. C. Smith H. Eisermann |
| spellingShingle |
C. Schannwell C. Schannwell R. Drews T. A. Ehlers O. Eisen O. Eisen C. Mayer M. Malinen E. C. Smith E. C. Smith H. Eisermann Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model The Cryosphere |
| author_facet |
C. Schannwell C. Schannwell R. Drews T. A. Ehlers O. Eisen O. Eisen C. Mayer M. Malinen E. C. Smith E. C. Smith H. Eisermann |
| author_sort |
C. Schannwell |
| title |
Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model |
| title_short |
Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model |
| title_full |
Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model |
| title_fullStr |
Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model |
| title_full_unstemmed |
Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model |
| title_sort |
quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-stokes model |
| publisher |
Copernicus Publications |
| series |
The Cryosphere |
| issn |
1994-0416 1994-0424 |
| publishDate |
2020-11-01 |
| description |
<p>Simulations of ice sheet evolution over glacial cycles require integration of observational constraints using ensemble studies with fast ice sheet models. These include physical parameterisations with uncertainties, for example, relating to grounding-line migration. More complete ice dynamic models are slow and have thus far only be applied for <span class="inline-formula"><</span> 1000 years, leaving many model parameters unconstrained. Here we apply a 3D thermomechanically coupled full-Stokes ice sheet model to the Ekström Ice Shelf embayment, East Antarctica, over a full glacial cycle (40 000 years). We test the model response to differing ocean bed properties that provide an envelope of potential ocean substrates seawards of today's grounding line. The end-member scenarios include a hard, high-friction ocean bed and a soft, low-friction ocean bed. We find that predicted ice volumes differ by <span class="inline-formula">></span> 50 % under almost equal forcing. Grounding-line positions differ by up to 49 km, show significant hysteresis, and migrate non-steadily in both scenarios with long quiescent phases disrupted by leaps of rapid migration. The simulations quantify the evolution of two different ice sheet geometries (namely thick and slow vs. thin and fast), triggered by the variable grounding-line migration over the differing ocean beds. Our study extends the timescales of 3D full-Stokes by an order of magnitude compared to previous studies with the help of parallelisation. The extended time frame for full-Stokes models is a first step towards better understanding other processes such as erosion and sediment redistribution in the ice shelf cavity impacting the entire catchment geometry.</p> |
| url |
https://tc.copernicus.org/articles/14/3917/2020/tc-14-3917-2020.pdf |
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