Seabed topography beneath Larsen C Ice Shelf from seismic soundings
Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-shelf bathymetry model derived from the inversion of IceBridge gravity data. A series of lines were collected, from the Churchill Peninsula in the north to the Joerg Peninsul...
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Language: | English |
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European Geosciences Union
2014
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Online Access: | http://nora.nerc.ac.uk/id/eprint/502846/ https://nora.nerc.ac.uk/id/eprint/502846/1/tc-8-1-2014.pdf |
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ftnerc:oai:nora.nerc.ac.uk:502846 2023-05-15T16:41:52+02:00 Seabed topography beneath Larsen C Ice Shelf from seismic soundings Brisbourne, Alex Smith, Andy King, Edward Nicholls, Keith Holland, Paul Makinson, Keith 2014-01-01 text http://nora.nerc.ac.uk/id/eprint/502846/ https://nora.nerc.ac.uk/id/eprint/502846/1/tc-8-1-2014.pdf en eng European Geosciences Union https://nora.nerc.ac.uk/id/eprint/502846/1/tc-8-1-2014.pdf Brisbourne, Alex orcid:0000-0002-9887-7120 Smith, Andy orcid:0000-0001-8577-482X King, Edward orcid:0000-0003-3793-3915 Nicholls, Keith orcid:0000-0002-2188-4509 Holland, Paul orcid:0000-0001-8370-289X Makinson, Keith orcid:0000-0002-5791-1767 . 2014 Seabed topography beneath Larsen C Ice Shelf from seismic soundings. The Cryosphere, 8. 1-13. https://doi.org/10.5194/tc-8-1-2014 <https://doi.org/10.5194/tc-8-1-2014> cc_by CC-BY Publication - Article PeerReviewed 2014 ftnerc https://doi.org/10.5194/tc-8-1-2014 2023-02-04T19:37:29Z Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-shelf bathymetry model derived from the inversion of IceBridge gravity data. A series of lines were collected, from the Churchill Peninsula in the north to the Joerg Peninsula in the south, and also towards the ice front. Sites were selected using the bathymetry model derived from the inversion of free-air gravity data to indicate key regions where sub-shelf oceanic circulation may be affected by ice draft and sub-shelf cavity thickness. The seismic velocity profile in the upper 100 m of firn and ice was derived from shallow refraction surveys at a number of locations. Measured temperatures within the ice column and at the ice base were used to define the velocity profile through the remainder of the ice column. Seismic velocities in the water column were derived from previous in situ measurements. Uncertainties in ice and water cavity thickness are in general <10 m. Compared with the seismic measurements, the root-mean-square error in the gravimetrically derived bathymetry at the seismic sites is 162 m. The seismic profiles prove the non-existence of several bathymetric features that are indicated in the gravity inversion model, significantly modifying the expected oceanic circulation beneath the ice shelf. Similar features have previously been shown to be highly significant in affecting basal melt rates predicted by ocean models. The discrepancies between the gravity inversion results and the seismic bathymetry are attributed to the assumption of uniform geology inherent in the gravity inversion process and also the sparsity of IceBridge flight lines. Results indicate that care must be taken when using bathymetry models derived by the inversion of free-air gravity anomalies. The bathymetry results presented here will be used to improve existing sub-shelf ocean circulation models. Article in Journal/Newspaper Ice Shelf The Cryosphere Natural Environment Research Council: NERC Open Research Archive Joerg ENVELOPE(-65.169,-65.169,-68.181,-68.181) Churchill Peninsula ENVELOPE(-62.781,-62.781,-66.440,-66.440) Joerg peninsula ENVELOPE(-65.169,-65.169,-68.181,-68.181) The Cryosphere 8 1 1 13 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-shelf bathymetry model derived from the inversion of IceBridge gravity data. A series of lines were collected, from the Churchill Peninsula in the north to the Joerg Peninsula in the south, and also towards the ice front. Sites were selected using the bathymetry model derived from the inversion of free-air gravity data to indicate key regions where sub-shelf oceanic circulation may be affected by ice draft and sub-shelf cavity thickness. The seismic velocity profile in the upper 100 m of firn and ice was derived from shallow refraction surveys at a number of locations. Measured temperatures within the ice column and at the ice base were used to define the velocity profile through the remainder of the ice column. Seismic velocities in the water column were derived from previous in situ measurements. Uncertainties in ice and water cavity thickness are in general <10 m. Compared with the seismic measurements, the root-mean-square error in the gravimetrically derived bathymetry at the seismic sites is 162 m. The seismic profiles prove the non-existence of several bathymetric features that are indicated in the gravity inversion model, significantly modifying the expected oceanic circulation beneath the ice shelf. Similar features have previously been shown to be highly significant in affecting basal melt rates predicted by ocean models. The discrepancies between the gravity inversion results and the seismic bathymetry are attributed to the assumption of uniform geology inherent in the gravity inversion process and also the sparsity of IceBridge flight lines. Results indicate that care must be taken when using bathymetry models derived by the inversion of free-air gravity anomalies. The bathymetry results presented here will be used to improve existing sub-shelf ocean circulation models. |
format |
Article in Journal/Newspaper |
author |
Brisbourne, Alex Smith, Andy King, Edward Nicholls, Keith Holland, Paul Makinson, Keith |
spellingShingle |
Brisbourne, Alex Smith, Andy King, Edward Nicholls, Keith Holland, Paul Makinson, Keith Seabed topography beneath Larsen C Ice Shelf from seismic soundings |
author_facet |
Brisbourne, Alex Smith, Andy King, Edward Nicholls, Keith Holland, Paul Makinson, Keith |
author_sort |
Brisbourne, Alex |
title |
Seabed topography beneath Larsen C Ice Shelf from seismic soundings |
title_short |
Seabed topography beneath Larsen C Ice Shelf from seismic soundings |
title_full |
Seabed topography beneath Larsen C Ice Shelf from seismic soundings |
title_fullStr |
Seabed topography beneath Larsen C Ice Shelf from seismic soundings |
title_full_unstemmed |
Seabed topography beneath Larsen C Ice Shelf from seismic soundings |
title_sort |
seabed topography beneath larsen c ice shelf from seismic soundings |
publisher |
European Geosciences Union |
publishDate |
2014 |
url |
http://nora.nerc.ac.uk/id/eprint/502846/ https://nora.nerc.ac.uk/id/eprint/502846/1/tc-8-1-2014.pdf |
long_lat |
ENVELOPE(-65.169,-65.169,-68.181,-68.181) ENVELOPE(-62.781,-62.781,-66.440,-66.440) ENVELOPE(-65.169,-65.169,-68.181,-68.181) |
geographic |
Joerg Churchill Peninsula Joerg peninsula |
geographic_facet |
Joerg Churchill Peninsula Joerg peninsula |
genre |
Ice Shelf The Cryosphere |
genre_facet |
Ice Shelf The Cryosphere |
op_relation |
https://nora.nerc.ac.uk/id/eprint/502846/1/tc-8-1-2014.pdf Brisbourne, Alex orcid:0000-0002-9887-7120 Smith, Andy orcid:0000-0001-8577-482X King, Edward orcid:0000-0003-3793-3915 Nicholls, Keith orcid:0000-0002-2188-4509 Holland, Paul orcid:0000-0001-8370-289X Makinson, Keith orcid:0000-0002-5791-1767 . 2014 Seabed topography beneath Larsen C Ice Shelf from seismic soundings. The Cryosphere, 8. 1-13. https://doi.org/10.5194/tc-8-1-2014 <https://doi.org/10.5194/tc-8-1-2014> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/tc-8-1-2014 |
container_title |
The Cryosphere |
container_volume |
8 |
container_issue |
1 |
container_start_page |
1 |
op_container_end_page |
13 |
_version_ |
1766032342406660096 |