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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2017
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Online Access: | http://nora.nerc.ac.uk/id/eprint/517805/ https://nora.nerc.ac.uk/id/eprint/517805/1/on_the_interpretation_of_iceshelf_flexure_measurements.pdf |
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ftnerc:oai:nora.nerc.ac.uk:517805 2023-05-15T16:41:51+02:00 On the interpretation of ice-shelf flexure measurements Rosier, Sebastian H.R. Marsh, Oliver J. Rack, Wolfgang Gudmundsson, G. Hilmar Wild, Christian T. Ryan, Michelle 2017-10 text http://nora.nerc.ac.uk/id/eprint/517805/ https://nora.nerc.ac.uk/id/eprint/517805/1/on_the_interpretation_of_iceshelf_flexure_measurements.pdf en eng https://nora.nerc.ac.uk/id/eprint/517805/1/on_the_interpretation_of_iceshelf_flexure_measurements.pdf Rosier, Sebastian H.R. orcid:0000-0003-3047-9908 Marsh, Oliver J.; Rack, Wolfgang; Gudmundsson, G. Hilmar orcid:0000-0003-4236-5369 Wild, Christian T.; Ryan, Michelle. 2017 On the interpretation of ice-shelf flexure measurements. Journal of Glaciology, 63 (241). 783-791. https://doi.org/10.1017/jog.2017.44 <https://doi.org/10.1017/jog.2017.44> cc_by_4 CC-BY Publication - Article PeerReviewed 2017 ftnerc https://doi.org/10.1017/jog.2017.44 2023-02-04T19:45:20Z 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 Shelf Journal of Glaciology McMurdo Ice Shelf Natural Environment Research Council: NERC Open Research Archive McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) Journal of Glaciology 63 241 783 791 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
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 Gudmundsson, G. Hilmar Wild, Christian T. Ryan, Michelle |
spellingShingle |
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 |
author_facet |
Rosier, Sebastian H.R. Marsh, Oliver J. Rack, Wolfgang Gudmundsson, 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://nora.nerc.ac.uk/id/eprint/517805/ https://nora.nerc.ac.uk/id/eprint/517805/1/on_the_interpretation_of_iceshelf_flexure_measurements.pdf |
long_lat |
ENVELOPE(166.500,166.500,-78.000,-78.000) |
geographic |
McMurdo Ice Shelf |
geographic_facet |
McMurdo Ice Shelf |
genre |
Ice Shelf Journal of Glaciology McMurdo Ice Shelf |
genre_facet |
Ice Shelf Journal of Glaciology McMurdo Ice Shelf |
op_relation |
https://nora.nerc.ac.uk/id/eprint/517805/1/on_the_interpretation_of_iceshelf_flexure_measurements.pdf Rosier, Sebastian H.R. orcid:0000-0003-3047-9908 Marsh, Oliver J.; Rack, Wolfgang; Gudmundsson, G. Hilmar orcid:0000-0003-4236-5369 Wild, Christian T.; Ryan, Michelle. 2017 On the interpretation of ice-shelf flexure measurements. Journal of Glaciology, 63 (241). 783-791. https://doi.org/10.1017/jog.2017.44 <https://doi.org/10.1017/jog.2017.44> |
op_rights |
cc_by_4 |
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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1766032325595889664 |