Effect of higher-order stress gradients on the centennial mass evolution of the Greenland ice sheet
We use a three-dimensional thermo-mechanically coupled model of the Greenland ice sheet to assess the effects of marginal perturbations on volume changes on centennial timescales. The model is designed to allow for five ice dynamic formulations using different approximations to the force balance. Th...
Published in: | The Cryosphere |
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Online Access: | https://doi.org/10.5194/tc-7-183-2013 https://tc.copernicus.org/articles/7/183/2013/ |
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ftcopernicus:oai:publications.copernicus.org:tc16095 2023-05-15T16:28:43+02:00 Effect of higher-order stress gradients on the centennial mass evolution of the Greenland ice sheet Fürst, J. J. Goelzer, H. Huybrechts, P. 2018-09-27 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/tc-7-183-2013 https://tc.copernicus.org/articles/7/183/2013/ eng eng info:eu-repo/grantAgreement/EC/FP7/226375 doi:10.5194/tc-7-183-2013 https://tc.copernicus.org/articles/7/183/2013/ info:eu-repo/semantics/openAccess eISSN: 1994-0424 info:eu-repo/semantics/Text 2018 ftcopernicus https://doi.org/10.5194/tc-7-183-2013 2020-07-20T16:25:35Z We use a three-dimensional thermo-mechanically coupled model of the Greenland ice sheet to assess the effects of marginal perturbations on volume changes on centennial timescales. The model is designed to allow for five ice dynamic formulations using different approximations to the force balance. The standard model is based on the shallow ice approximation for both ice deformation and basal sliding. A second model version relies on a higher-order Blatter/Pattyn type of core that resolves effects from gradients in longitudinal stresses and transverse horizontal shearing, i.e. membrane-like stresses. Together with three intermediate model versions, these five versions allow for gradually more dynamic feedbacks from membrane stresses. Idealised experiments are conducted on various resolutions to compare the time-dependent response to imposed accelerations at the marine ice front. If such marginal accelerations are to have an appreciable effect on total mass loss on a century timescale, a fast mechanism to transmit such perturbations inland is required. While the forcing is independent of the model version, inclusion of direct horizontal coupling allows the initial speed-up to reach several tens of kilometres inland. Within one century, effects from gradients in membrane stress alter the inland signal propagation and transmit additional dynamic thinning to the ice sheet interior. But the centennial overall volume loss differs only by some percents from the standard model, as the dominant response is a diffusive inland propagation of geometric changes. For the experiments considered, this volume response is even attenuated by direct horizontal coupling. The reason is a faster adjustment of the sliding regime by instant stress transmission in models that account for the effect of membrane stresses. Ultimately, horizontal coupling decreases the reaction time to perturbations at the ice sheet margin. These findings suggest that for modelling the mass evolution of a large-scale ice sheet, effects from diffusive geometric adjustments dominate effects from successively more complete dynamic approaches. Other/Unknown Material Greenland Ice Sheet Copernicus Publications: E-Journals Greenland The Cryosphere 7 1 183 199 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
We use a three-dimensional thermo-mechanically coupled model of the Greenland ice sheet to assess the effects of marginal perturbations on volume changes on centennial timescales. The model is designed to allow for five ice dynamic formulations using different approximations to the force balance. The standard model is based on the shallow ice approximation for both ice deformation and basal sliding. A second model version relies on a higher-order Blatter/Pattyn type of core that resolves effects from gradients in longitudinal stresses and transverse horizontal shearing, i.e. membrane-like stresses. Together with three intermediate model versions, these five versions allow for gradually more dynamic feedbacks from membrane stresses. Idealised experiments are conducted on various resolutions to compare the time-dependent response to imposed accelerations at the marine ice front. If such marginal accelerations are to have an appreciable effect on total mass loss on a century timescale, a fast mechanism to transmit such perturbations inland is required. While the forcing is independent of the model version, inclusion of direct horizontal coupling allows the initial speed-up to reach several tens of kilometres inland. Within one century, effects from gradients in membrane stress alter the inland signal propagation and transmit additional dynamic thinning to the ice sheet interior. But the centennial overall volume loss differs only by some percents from the standard model, as the dominant response is a diffusive inland propagation of geometric changes. For the experiments considered, this volume response is even attenuated by direct horizontal coupling. The reason is a faster adjustment of the sliding regime by instant stress transmission in models that account for the effect of membrane stresses. Ultimately, horizontal coupling decreases the reaction time to perturbations at the ice sheet margin. These findings suggest that for modelling the mass evolution of a large-scale ice sheet, effects from diffusive geometric adjustments dominate effects from successively more complete dynamic approaches. |
format |
Other/Unknown Material |
author |
Fürst, J. J. Goelzer, H. Huybrechts, P. |
spellingShingle |
Fürst, J. J. Goelzer, H. Huybrechts, P. Effect of higher-order stress gradients on the centennial mass evolution of the Greenland ice sheet |
author_facet |
Fürst, J. J. Goelzer, H. Huybrechts, P. |
author_sort |
Fürst, J. J. |
title |
Effect of higher-order stress gradients on the centennial mass evolution of the Greenland ice sheet |
title_short |
Effect of higher-order stress gradients on the centennial mass evolution of the Greenland ice sheet |
title_full |
Effect of higher-order stress gradients on the centennial mass evolution of the Greenland ice sheet |
title_fullStr |
Effect of higher-order stress gradients on the centennial mass evolution of the Greenland ice sheet |
title_full_unstemmed |
Effect of higher-order stress gradients on the centennial mass evolution of the Greenland ice sheet |
title_sort |
effect of higher-order stress gradients on the centennial mass evolution of the greenland ice sheet |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-7-183-2013 https://tc.copernicus.org/articles/7/183/2013/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/226375 doi:10.5194/tc-7-183-2013 https://tc.copernicus.org/articles/7/183/2013/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-7-183-2013 |
container_title |
The Cryosphere |
container_volume |
7 |
container_issue |
1 |
container_start_page |
183 |
op_container_end_page |
199 |
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1766018395328741376 |