Modelling Greenland Outlet Glaciers
The objective of this project was to develop simple yet realistic models of Greenland outlet glaciers to better understand ongoing changes and to identify possible causes for these changes. Several approaches can be taken to evaluate the interaction between climate forcing and ice dynamics, and the...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20020012645 2023-05-15T16:21:26+02:00 Modelling Greenland Outlet Glaciers vanderVeen, Cornelis Abdalati, Waleed Unclassified, Unlimited, Publicly available Dec. 27, 2001 application/pdf http://hdl.handle.net/2060/20020012645 unknown Document ID: 20020012645 http://hdl.handle.net/2060/20020012645 No Copyright CASI Oceanography 2001 ftnasantrs 2019-07-21T02:41:50Z The objective of this project was to develop simple yet realistic models of Greenland outlet glaciers to better understand ongoing changes and to identify possible causes for these changes. Several approaches can be taken to evaluate the interaction between climate forcing and ice dynamics, and the consequent ice-sheet response, which may involve changes in flow style. To evaluate the icesheet response to mass-balance forcing, Van der Veen (Journal of Geophysical Research, in press) makes the assumption that this response can be considered a perturbation on the reference state and may be evaluated separately from how this reference state evolves over time. Mass-balance forcing has an immediate effect on the ice sheet. Initially, the rate of thickness change as compared to the reference state equals the perturbation in snowfall or ablation. If the forcing persists, the ice sheet responds dynamically, adjusting the rate at which ice is evacuated from the interior to the margins, to achieve a new equilibrium. For large ice sheets, this dynamic adjustment may last for thousands of years, with the magnitude of change decreasing steadily over time as a new equilibrium is approached. This response can be described using kinematic wave theory. This theory, modified to pertain to Greenland drainage basins, was used to evaluate possible ice-sheet responses to perturbations in surface mass balance. The reference state is defined based on measurements along the central flowline of Petermann Glacier in north-west Greenland, and perturbations on this state considered. The advantage of this approach is that the particulars of the dynamical flow regime need not be explicitly known but are incorporated through the parameterization of the reference ice flux or longitudinal velocity profile. The results of the kinematic wave model indicate that significant rates of thickness change can occur immediately after the prescribed change in surface mass balance but adjustments in flow rapidly diminish these rates to a few cm/yr at most. The time scale for adjustment is of the order of a thousand years or so. Other/Unknown Material glacier Greenland Ice Sheet Petermann glacier NASA Technical Reports Server (NTRS) Greenland |
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Open Polar |
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NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Oceanography |
spellingShingle |
Oceanography vanderVeen, Cornelis Abdalati, Waleed Modelling Greenland Outlet Glaciers |
topic_facet |
Oceanography |
description |
The objective of this project was to develop simple yet realistic models of Greenland outlet glaciers to better understand ongoing changes and to identify possible causes for these changes. Several approaches can be taken to evaluate the interaction between climate forcing and ice dynamics, and the consequent ice-sheet response, which may involve changes in flow style. To evaluate the icesheet response to mass-balance forcing, Van der Veen (Journal of Geophysical Research, in press) makes the assumption that this response can be considered a perturbation on the reference state and may be evaluated separately from how this reference state evolves over time. Mass-balance forcing has an immediate effect on the ice sheet. Initially, the rate of thickness change as compared to the reference state equals the perturbation in snowfall or ablation. If the forcing persists, the ice sheet responds dynamically, adjusting the rate at which ice is evacuated from the interior to the margins, to achieve a new equilibrium. For large ice sheets, this dynamic adjustment may last for thousands of years, with the magnitude of change decreasing steadily over time as a new equilibrium is approached. This response can be described using kinematic wave theory. This theory, modified to pertain to Greenland drainage basins, was used to evaluate possible ice-sheet responses to perturbations in surface mass balance. The reference state is defined based on measurements along the central flowline of Petermann Glacier in north-west Greenland, and perturbations on this state considered. The advantage of this approach is that the particulars of the dynamical flow regime need not be explicitly known but are incorporated through the parameterization of the reference ice flux or longitudinal velocity profile. The results of the kinematic wave model indicate that significant rates of thickness change can occur immediately after the prescribed change in surface mass balance but adjustments in flow rapidly diminish these rates to a few cm/yr at most. The time scale for adjustment is of the order of a thousand years or so. |
author |
vanderVeen, Cornelis Abdalati, Waleed |
author_facet |
vanderVeen, Cornelis Abdalati, Waleed |
author_sort |
vanderVeen, Cornelis |
title |
Modelling Greenland Outlet Glaciers |
title_short |
Modelling Greenland Outlet Glaciers |
title_full |
Modelling Greenland Outlet Glaciers |
title_fullStr |
Modelling Greenland Outlet Glaciers |
title_full_unstemmed |
Modelling Greenland Outlet Glaciers |
title_sort |
modelling greenland outlet glaciers |
publishDate |
2001 |
url |
http://hdl.handle.net/2060/20020012645 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland Ice Sheet Petermann glacier |
genre_facet |
glacier Greenland Ice Sheet Petermann glacier |
op_source |
CASI |
op_relation |
Document ID: 20020012645 http://hdl.handle.net/2060/20020012645 |
op_rights |
No Copyright |
_version_ |
1766009435918958592 |