On the interpretation of ice-shelf flexure measurements
Tidal flexure in ice shelf grounding zones has been used extensively in the past to determine grounding line position and ice properties. Although the rheology of ice is viscoelastic at tidal loading frequencies, most modelling studies have assumed some form of linear elastic beam approximation to m...
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Online Access: | http://hdl.handle.net/10092/15129 https://doi.org/10.1017/jog.2017.44 |
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ftunivcanter:oai:ir.canterbury.ac.nz:10092/15129 2023-05-15T16:41:12+02:00 On the interpretation of ice-shelf flexure measurements Rosier, Sebastian H R Marsh, Oliver J Rack, Wolfgang Gundmundsson, G Hilmar Wild, Christian T Ryan, Michelle 2017-09-17T22:19:56Z application/pdf http://hdl.handle.net/10092/15129 https://doi.org/10.1017/jog.2017.44 en eng ROSIER SEBASTIAN H R, MARSH OLIVER J, RACK WOLFGANG, GUDMUNDSSON G HILMAR, WILD CHRISTIAN T, RYAN MICHELLE On the interpretation of ice-shelf flexure measurements. Journal of Glaciology. 1-9. 0022-1430 1727-5652 http://hdl.handle.net/10092/15129 https://doi.org/10.1017/jog.2017.44 © The Author(s) 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. CC-BY ice/ocean interactions ice shelves ice rheology ice-sheet modelling Fields of Research::37 - Earth sciences::3709 - Physical geography and environmental geoscience::370902 - Glaciology Journal Article 2017 ftunivcanter https://doi.org/10.1017/jog.2017.44 2022-09-08T13:40:50Z Tidal flexure in ice shelf grounding zones has been used extensively in the past to determine grounding line position and ice properties. Although the rheology of ice is viscoelastic at tidal loading frequencies, most modelling studies have assumed some form of linear elastic beam approximation to match observed flexure profiles. Here we use density, radar and DInSAR measurements in combination with full-Stokes viscoelastic modelling to investigate a range of additional controls on the flexure of the Southern McMurdo Ice Shelf. We find that inclusion of observed basal crevasses and density dependent ice stiffness can greatly alter the flexure profile and yet fitting a simple elastic beam model to that profile will still produce an excellent fit. Estimates of the effective Young’s modulus derived by fitting flexure profiles are shown to vary by over 200% depending on whether these factors are included, even when the local thickness is well constrained. Conversely, estimates of the grounding line position are relatively insensitive to these considerations for the case of a steep bed slope in our study region. By fitting tidal amplitudes only, and ignoring phase information, elastic beam theory can provide a good fit to observations in a wide variety of situations. This should, however, not be taken as an indication that the underlying rheological assumptions are correct. Article in Journal/Newspaper Ice Sheet Ice Shelf Ice Shelves Journal of Glaciology McMurdo Ice Shelf University of Canterbury, Christchurch: UC Research Repository McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) Journal of Glaciology 63 241 783 791 |
institution |
Open Polar |
collection |
University of Canterbury, Christchurch: UC Research Repository |
op_collection_id |
ftunivcanter |
language |
English |
topic |
ice/ocean interactions ice shelves ice rheology ice-sheet modelling Fields of Research::37 - Earth sciences::3709 - Physical geography and environmental geoscience::370902 - Glaciology |
spellingShingle |
ice/ocean interactions ice shelves ice rheology ice-sheet modelling Fields of Research::37 - Earth sciences::3709 - Physical geography and environmental geoscience::370902 - Glaciology Rosier, Sebastian H R Marsh, Oliver J Rack, Wolfgang Gundmundsson, G Hilmar Wild, Christian T Ryan, Michelle On the interpretation of ice-shelf flexure measurements |
topic_facet |
ice/ocean interactions ice shelves ice rheology ice-sheet modelling Fields of Research::37 - Earth sciences::3709 - Physical geography and environmental geoscience::370902 - Glaciology |
description |
Tidal flexure in ice shelf grounding zones has been used extensively in the past to determine grounding line position and ice properties. Although the rheology of ice is viscoelastic at tidal loading frequencies, most modelling studies have assumed some form of linear elastic beam approximation to match observed flexure profiles. Here we use density, radar and DInSAR measurements in combination with full-Stokes viscoelastic modelling to investigate a range of additional controls on the flexure of the Southern McMurdo Ice Shelf. We find that inclusion of observed basal crevasses and density dependent ice stiffness can greatly alter the flexure profile and yet fitting a simple elastic beam model to that profile will still produce an excellent fit. Estimates of the effective Young’s modulus derived by fitting flexure profiles are shown to vary by over 200% depending on whether these factors are included, even when the local thickness is well constrained. Conversely, estimates of the grounding line position are relatively insensitive to these considerations for the case of a steep bed slope in our study region. By fitting tidal amplitudes only, and ignoring phase information, elastic beam theory can provide a good fit to observations in a wide variety of situations. This should, however, not be taken as an indication that the underlying rheological assumptions are correct. |
format |
Article in Journal/Newspaper |
author |
Rosier, Sebastian H R Marsh, Oliver J Rack, Wolfgang Gundmundsson, G Hilmar Wild, Christian T Ryan, Michelle |
author_facet |
Rosier, Sebastian H R Marsh, Oliver J Rack, Wolfgang Gundmundsson, G Hilmar Wild, Christian T Ryan, Michelle |
author_sort |
Rosier, Sebastian H R |
title |
On the interpretation of ice-shelf flexure measurements |
title_short |
On the interpretation of ice-shelf flexure measurements |
title_full |
On the interpretation of ice-shelf flexure measurements |
title_fullStr |
On the interpretation of ice-shelf flexure measurements |
title_full_unstemmed |
On the interpretation of ice-shelf flexure measurements |
title_sort |
on the interpretation of ice-shelf flexure measurements |
publishDate |
2017 |
url |
http://hdl.handle.net/10092/15129 https://doi.org/10.1017/jog.2017.44 |
long_lat |
ENVELOPE(166.500,166.500,-78.000,-78.000) |
geographic |
McMurdo Ice Shelf |
geographic_facet |
McMurdo Ice Shelf |
genre |
Ice Sheet Ice Shelf Ice Shelves Journal of Glaciology McMurdo Ice Shelf |
genre_facet |
Ice Sheet Ice Shelf Ice Shelves Journal of Glaciology McMurdo Ice Shelf |
op_relation |
ROSIER SEBASTIAN H R, MARSH OLIVER J, RACK WOLFGANG, GUDMUNDSSON G HILMAR, WILD CHRISTIAN T, RYAN MICHELLE On the interpretation of ice-shelf flexure measurements. Journal of Glaciology. 1-9. 0022-1430 1727-5652 http://hdl.handle.net/10092/15129 https://doi.org/10.1017/jog.2017.44 |
op_rights |
© The Author(s) 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1017/jog.2017.44 |
container_title |
Journal of Glaciology |
container_volume |
63 |
container_issue |
241 |
container_start_page |
783 |
op_container_end_page |
791 |
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1766031636761149440 |