Relevance of detail in basal topography for basal slipperiness inversions: a case study on Pine Island Glacier, Antarctica
Given high-resolution satellite-derived surface elevation and velocity data, ice-sheet models generally estimate mechanical basal boundary conditions using surface-to-bed inversion methods. In this work, we address the sensitivity of results from inversion methods to the accuracy of the bed elevatio...
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Online Access: | https://doi.org/10.3389/feart.2018.00033 https://ora.ox.ac.uk/objects/uuid:5b26707c-c986-408d-9b01-5d959f9b04c4 |
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ftuloxford:oai:ora.ox.ac.uk:uuid:5b26707c-c986-408d-9b01-5d959f9b04c4 2024-09-30T14:23:22+00:00 Relevance of detail in basal topography for basal slipperiness inversions: a case study on Pine Island Glacier, Antarctica Kyrke-Smith, T Gudmundsson, G Farrell, P 2018-04-06 https://doi.org/10.3389/feart.2018.00033 https://ora.ox.ac.uk/objects/uuid:5b26707c-c986-408d-9b01-5d959f9b04c4 unknown Frontiers Media doi:10.3389/feart.2018.00033 https://ora.ox.ac.uk/objects/uuid:5b26707c-c986-408d-9b01-5d959f9b04c4 https://doi.org/10.3389/feart.2018.00033 info:eu-repo/semantics/openAccess CC Attribution (CC BY) Journal article 2018 ftuloxford https://doi.org/10.3389/feart.2018.00033 2024-09-06T07:47:34Z Given high-resolution satellite-derived surface elevation and velocity data, ice-sheet models generally estimate mechanical basal boundary conditions using surface-to-bed inversion methods. In this work, we address the sensitivity of results from inversion methods to the accuracy of the bed elevation data on Pine Island Glacier. We show that misfit between observations and model output is reduced when high-resolution bed topography is used in the inverse model. By looking at results with a range of detail included in the bed elevation, we consider the separation of basal drag due to the bed topography (form drag) and that due to inherent bed properties (skin drag). The mean value of basal shear stress is reduced when more detailed topography is included in the model. This suggests that without a fully resolved bed a significant amount of the basal shear stress recovered from inversion methods may be due to the unresolved bed topography. However, the spatial structure of the retrieved fields is robust as the bed accuracy is varied; the fields are instead sensitive to the degree of regularisation applied to the inversion. While the implications for the future temporal evolution of PIG are not quantified here directly, our work raises the possibility that skin drag may be overestimated in the current generation of numerical ice-sheet models of this area. These shortcomings could be overcome by inverting simultaneously for both bed topography and basal slipperiness. Article in Journal/Newspaper Antarc* Antarctica Ice Sheet Pine Island Pine Island Glacier ORA - Oxford University Research Archive Pine Island Glacier ENVELOPE(-101.000,-101.000,-75.000,-75.000) Frontiers in Earth Science 6 |
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Open Polar |
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ORA - Oxford University Research Archive |
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ftuloxford |
language |
unknown |
description |
Given high-resolution satellite-derived surface elevation and velocity data, ice-sheet models generally estimate mechanical basal boundary conditions using surface-to-bed inversion methods. In this work, we address the sensitivity of results from inversion methods to the accuracy of the bed elevation data on Pine Island Glacier. We show that misfit between observations and model output is reduced when high-resolution bed topography is used in the inverse model. By looking at results with a range of detail included in the bed elevation, we consider the separation of basal drag due to the bed topography (form drag) and that due to inherent bed properties (skin drag). The mean value of basal shear stress is reduced when more detailed topography is included in the model. This suggests that without a fully resolved bed a significant amount of the basal shear stress recovered from inversion methods may be due to the unresolved bed topography. However, the spatial structure of the retrieved fields is robust as the bed accuracy is varied; the fields are instead sensitive to the degree of regularisation applied to the inversion. While the implications for the future temporal evolution of PIG are not quantified here directly, our work raises the possibility that skin drag may be overestimated in the current generation of numerical ice-sheet models of this area. These shortcomings could be overcome by inverting simultaneously for both bed topography and basal slipperiness. |
format |
Article in Journal/Newspaper |
author |
Kyrke-Smith, T Gudmundsson, G Farrell, P |
spellingShingle |
Kyrke-Smith, T Gudmundsson, G Farrell, P Relevance of detail in basal topography for basal slipperiness inversions: a case study on Pine Island Glacier, Antarctica |
author_facet |
Kyrke-Smith, T Gudmundsson, G Farrell, P |
author_sort |
Kyrke-Smith, T |
title |
Relevance of detail in basal topography for basal slipperiness inversions: a case study on Pine Island Glacier, Antarctica |
title_short |
Relevance of detail in basal topography for basal slipperiness inversions: a case study on Pine Island Glacier, Antarctica |
title_full |
Relevance of detail in basal topography for basal slipperiness inversions: a case study on Pine Island Glacier, Antarctica |
title_fullStr |
Relevance of detail in basal topography for basal slipperiness inversions: a case study on Pine Island Glacier, Antarctica |
title_full_unstemmed |
Relevance of detail in basal topography for basal slipperiness inversions: a case study on Pine Island Glacier, Antarctica |
title_sort |
relevance of detail in basal topography for basal slipperiness inversions: a case study on pine island glacier, antarctica |
publisher |
Frontiers Media |
publishDate |
2018 |
url |
https://doi.org/10.3389/feart.2018.00033 https://ora.ox.ac.uk/objects/uuid:5b26707c-c986-408d-9b01-5d959f9b04c4 |
long_lat |
ENVELOPE(-101.000,-101.000,-75.000,-75.000) |
geographic |
Pine Island Glacier |
geographic_facet |
Pine Island Glacier |
genre |
Antarc* Antarctica Ice Sheet Pine Island Pine Island Glacier |
genre_facet |
Antarc* Antarctica Ice Sheet Pine Island Pine Island Glacier |
op_relation |
doi:10.3389/feart.2018.00033 https://ora.ox.ac.uk/objects/uuid:5b26707c-c986-408d-9b01-5d959f9b04c4 https://doi.org/10.3389/feart.2018.00033 |
op_rights |
info:eu-repo/semantics/openAccess CC Attribution (CC BY) |
op_doi |
https://doi.org/10.3389/feart.2018.00033 |
container_title |
Frontiers in Earth Science |
container_volume |
6 |
_version_ |
1811637294240628736 |