From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model
Here we report on a cyclic, physical ice-discharge instability in the Parallel Ice Sheet Model, simulating the flow of a three-dimensional, inherently buttressed ice-sheet-shelf system which periodically surges on a millennial timescale. The thermomechanically coupled model on 1 km horizontal resolu...
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ftcopernicus:oai:publications.copernicus.org:tc55324 2023-05-15T13:54:27+02:00 From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model Feldmann, Johannes Levermann, Anders 2018-09-27 application/pdf https://doi.org/10.5194/tc-11-1913-2017 https://tc.copernicus.org/articles/11/1913/2017/ eng eng doi:10.5194/tc-11-1913-2017 https://tc.copernicus.org/articles/11/1913/2017/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-11-1913-2017 2020-07-20T16:23:38Z Here we report on a cyclic, physical ice-discharge instability in the Parallel Ice Sheet Model, simulating the flow of a three-dimensional, inherently buttressed ice-sheet-shelf system which periodically surges on a millennial timescale. The thermomechanically coupled model on 1 km horizontal resolution includes an enthalpy-based formulation of the thermodynamics, a nonlinear stress-balance-based sliding law and a very simple subglacial hydrology. The simulated unforced surging is characterized by rapid ice streaming through a bed trough, resulting in abrupt discharge of ice across the grounding line which is eventually calved into the ocean. We visualize the central feedbacks that dominate the subsequent phases of ice buildup, surge and stabilization which emerge from the interaction between ice dynamics, thermodynamics and the subglacial till layer. Results from the variation of surface mass balance and basal roughness suggest that ice sheets of medium thickness may be more susceptible to surging than relatively thin or thick ones for which the surge feedback loop is damped. We also investigate the influence of different basal sliding laws (ranging from purely plastic to nonlinear to linear) on possible surging. The presented mechanisms underlying our simulations of self-maintained, periodic ice growth and destabilization may play a role in large-scale ice-sheet surging, such as the surging of the Laurentide Ice Sheet, which is associated with Heinrich events, and ice-stream shutdown and reactivation, such as observed in the Siple Coast region of West Antarctica. Text Antarc* Antarctica Ice Sheet West Antarctica Copernicus Publications: E-Journals Siple ENVELOPE(-83.917,-83.917,-75.917,-75.917) Siple Coast ENVELOPE(-155.000,-155.000,-82.000,-82.000) West Antarctica The Cryosphere 11 4 1913 1932 |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Here we report on a cyclic, physical ice-discharge instability in the Parallel Ice Sheet Model, simulating the flow of a three-dimensional, inherently buttressed ice-sheet-shelf system which periodically surges on a millennial timescale. The thermomechanically coupled model on 1 km horizontal resolution includes an enthalpy-based formulation of the thermodynamics, a nonlinear stress-balance-based sliding law and a very simple subglacial hydrology. The simulated unforced surging is characterized by rapid ice streaming through a bed trough, resulting in abrupt discharge of ice across the grounding line which is eventually calved into the ocean. We visualize the central feedbacks that dominate the subsequent phases of ice buildup, surge and stabilization which emerge from the interaction between ice dynamics, thermodynamics and the subglacial till layer. Results from the variation of surface mass balance and basal roughness suggest that ice sheets of medium thickness may be more susceptible to surging than relatively thin or thick ones for which the surge feedback loop is damped. We also investigate the influence of different basal sliding laws (ranging from purely plastic to nonlinear to linear) on possible surging. The presented mechanisms underlying our simulations of self-maintained, periodic ice growth and destabilization may play a role in large-scale ice-sheet surging, such as the surging of the Laurentide Ice Sheet, which is associated with Heinrich events, and ice-stream shutdown and reactivation, such as observed in the Siple Coast region of West Antarctica. |
format |
Text |
author |
Feldmann, Johannes Levermann, Anders |
spellingShingle |
Feldmann, Johannes Levermann, Anders From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model |
author_facet |
Feldmann, Johannes Levermann, Anders |
author_sort |
Feldmann, Johannes |
title |
From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model |
title_short |
From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model |
title_full |
From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model |
title_fullStr |
From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model |
title_full_unstemmed |
From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model |
title_sort |
from cyclic ice streaming to heinrich-like events: the grow-and-surge instability in the parallel ice sheet model |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-11-1913-2017 https://tc.copernicus.org/articles/11/1913/2017/ |
long_lat |
ENVELOPE(-83.917,-83.917,-75.917,-75.917) ENVELOPE(-155.000,-155.000,-82.000,-82.000) |
geographic |
Siple Siple Coast West Antarctica |
geographic_facet |
Siple Siple Coast West Antarctica |
genre |
Antarc* Antarctica Ice Sheet West Antarctica |
genre_facet |
Antarc* Antarctica Ice Sheet West Antarctica |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-11-1913-2017 https://tc.copernicus.org/articles/11/1913/2017/ |
op_doi |
https://doi.org/10.5194/tc-11-1913-2017 |
container_title |
The Cryosphere |
container_volume |
11 |
container_issue |
4 |
container_start_page |
1913 |
op_container_end_page |
1932 |
_version_ |
1766260320712523776 |