A quasi-analytical ice-sheet model for climate studies
A simple quasi-analytical model is developed to study the response of ice-sheets to climate change. The model is axisymmetrical and rests on a bed with a constant slope. The mechanics are highly parameterised. The climatic conditions are represented by the altitude of the runoff line. Above the runo...
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ftdoajarticles:oai:doaj.org/article:2f2456caa8ce4cf99f5d3dfd976b3858 2023-05-15T16:13:09+02:00 A quasi-analytical ice-sheet model for climate studies J. Oerlemans 2003-01-01T00:00:00Z https://doaj.org/article/2f2456caa8ce4cf99f5d3dfd976b3858 EN eng Copernicus Publications http://www.nonlin-processes-geophys.net/10/441/2003/npg-10-441-2003.pdf https://doaj.org/toc/1023-5809 https://doaj.org/toc/1607-7946 1023-5809 1607-7946 https://doaj.org/article/2f2456caa8ce4cf99f5d3dfd976b3858 Nonlinear Processes in Geophysics, Vol 10, Iss 4/5, Pp 441-452 (2003) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2003 ftdoajarticles 2022-12-31T10:36:17Z A simple quasi-analytical model is developed to study the response of ice-sheets to climate change. The model is axisymmetrical and rests on a bed with a constant slope. The mechanics are highly parameterised. The climatic conditions are represented by the altitude of the runoff line. Above the runoff line the accumulation rate is constant (but may depend on, for instance, the ice-sheet size), below the runoff line the balance gradient is constant. The ice-sheet may extend into the sea and can respond to changes in sea level. At the grounding line the ice velocity is assumed to be proportional to the water depth. For this set-up an explicit expression for the total mass budget of the ice-sheet is derived. To illustrate the properties and possibilities of the model, equilibrium states are analysed and the response to periodic forcing is studied as well. The coupling of mass balance and surface elevation of the ice-sheet leads to nonlinear behaviour and branching of the equilibrium solutions. The qualitative behaviour of the system is that of the cusp catastrophe. Nonlinear effects are more pronounced when the slope of the bed is smaller. A case is discussed in which two ice-sheets are coupled by making the altitude of the runoff line dependent on the total area of the two ice-sheets. On two continents, having a slightly different glaciation threshold, periodic forcing of the altitude of the runoff line is imposed. It is shown that in such a situation variations on a long time scale (two to three times the period of the forcing) are introduced. Finally the model is forced by the GISP d 18 O record for the last 120 000 years. For an appropriate choice of parameters the model simulates well the waxing and waning of the Laurentide, Fennoscandian and Barentsz ice-sheets. Article in Journal/Newspaper Fennoscandian Ice Sheet Directory of Open Access Journals: DOAJ Articles |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 J. Oerlemans A quasi-analytical ice-sheet model for climate studies |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
A simple quasi-analytical model is developed to study the response of ice-sheets to climate change. The model is axisymmetrical and rests on a bed with a constant slope. The mechanics are highly parameterised. The climatic conditions are represented by the altitude of the runoff line. Above the runoff line the accumulation rate is constant (but may depend on, for instance, the ice-sheet size), below the runoff line the balance gradient is constant. The ice-sheet may extend into the sea and can respond to changes in sea level. At the grounding line the ice velocity is assumed to be proportional to the water depth. For this set-up an explicit expression for the total mass budget of the ice-sheet is derived. To illustrate the properties and possibilities of the model, equilibrium states are analysed and the response to periodic forcing is studied as well. The coupling of mass balance and surface elevation of the ice-sheet leads to nonlinear behaviour and branching of the equilibrium solutions. The qualitative behaviour of the system is that of the cusp catastrophe. Nonlinear effects are more pronounced when the slope of the bed is smaller. A case is discussed in which two ice-sheets are coupled by making the altitude of the runoff line dependent on the total area of the two ice-sheets. On two continents, having a slightly different glaciation threshold, periodic forcing of the altitude of the runoff line is imposed. It is shown that in such a situation variations on a long time scale (two to three times the period of the forcing) are introduced. Finally the model is forced by the GISP d 18 O record for the last 120 000 years. For an appropriate choice of parameters the model simulates well the waxing and waning of the Laurentide, Fennoscandian and Barentsz ice-sheets. |
format |
Article in Journal/Newspaper |
author |
J. Oerlemans |
author_facet |
J. Oerlemans |
author_sort |
J. Oerlemans |
title |
A quasi-analytical ice-sheet model for climate studies |
title_short |
A quasi-analytical ice-sheet model for climate studies |
title_full |
A quasi-analytical ice-sheet model for climate studies |
title_fullStr |
A quasi-analytical ice-sheet model for climate studies |
title_full_unstemmed |
A quasi-analytical ice-sheet model for climate studies |
title_sort |
quasi-analytical ice-sheet model for climate studies |
publisher |
Copernicus Publications |
publishDate |
2003 |
url |
https://doaj.org/article/2f2456caa8ce4cf99f5d3dfd976b3858 |
genre |
Fennoscandian Ice Sheet |
genre_facet |
Fennoscandian Ice Sheet |
op_source |
Nonlinear Processes in Geophysics, Vol 10, Iss 4/5, Pp 441-452 (2003) |
op_relation |
http://www.nonlin-processes-geophys.net/10/441/2003/npg-10-441-2003.pdf https://doaj.org/toc/1023-5809 https://doaj.org/toc/1607-7946 1023-5809 1607-7946 https://doaj.org/article/2f2456caa8ce4cf99f5d3dfd976b3858 |
_version_ |
1765998763518722048 |