Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing
We use borehole optical televiewing (OPTV) to explore the internal structure of Larsen C Ice Shelf (LCIS). We report a suite of five ~90 m long OPTV logs, recording a light-emitting diode-illuminated, geometrically correct image of the borehole wall, from the northern and central sectors of LCIS col...
Published in: | Journal of Geophysical Research: Earth Surface |
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Format: | Article in Journal/Newspaper |
Language: | English |
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2017
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Online Access: | https://risweb.st-andrews.ac.uk/portal/en/researchoutput/ice-and-firn-heterogeneity-within-larsen-c-ice-shelf-from-borehole-optical-televiewing(cb91507b-2b5d-47df-98d5-ae2cb0ec5b9d).html https://doi.org/10.1002/2016JF004047 https://research-repository.st-andrews.ac.uk/bitstream/10023/10881/1/Sevestre_2017_JGRES_LarsenCIceShelf_CC.pdf |
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ftunstandrewcris:oai:risweb.st-andrews.ac.uk:publications/cb91507b-2b5d-47df-98d5-ae2cb0ec5b9d 2023-05-15T13:39:30+02:00 Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing Ashmore, David W. Hubbard, Bryn Luckman, Adrian Kulessa, Bernd Bevan, Suzanne Booth, Adam Munneke, Peter Kuipers O'Leary, Martin Sevestre, Heidi Holland, Paul R. 2017-05 application/pdf https://risweb.st-andrews.ac.uk/portal/en/researchoutput/ice-and-firn-heterogeneity-within-larsen-c-ice-shelf-from-borehole-optical-televiewing(cb91507b-2b5d-47df-98d5-ae2cb0ec5b9d).html https://doi.org/10.1002/2016JF004047 https://research-repository.st-andrews.ac.uk/bitstream/10023/10881/1/Sevestre_2017_JGRES_LarsenCIceShelf_CC.pdf eng eng info:eu-repo/semantics/openAccess Ashmore , D W , Hubbard , B , Luckman , A , Kulessa , B , Bevan , S , Booth , A , Munneke , P K , O'Leary , M , Sevestre , H & Holland , P R 2017 , ' Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing ' , Journal of Geophysical Research - Earth Surface , vol. 122 , no. 5 , pp. 1139-1153 . https://doi.org/10.1002/2016JF004047 Ice shelves Glaciology Antarctica article 2017 ftunstandrewcris https://doi.org/10.1002/2016JF004047 2022-06-02T07:47:33Z We use borehole optical televiewing (OPTV) to explore the internal structure of Larsen C Ice Shelf (LCIS). We report a suite of five ~90 m long OPTV logs, recording a light-emitting diode-illuminated, geometrically correct image of the borehole wall, from the northern and central sectors of LCIS collected during austral spring 2014 and 2015. We use a thresholding-based technique to estimate the refrozen ice content of the ice column and exploit a recently calibrated density-luminosity relationship to reveal its structure. All sites are dense and strongly influenced by surface melt, with frequent refrozen ice layers and mean densities, between the depths of 1.87 and 90 m, ranging from 862 to 894 kg m −3 . We define four distinct units that comprise LCIS and relate these to ice provenance, dynamic history, and past melt events. These units are in situ meteoric ice with infiltration ice (U1), meteoric ice which has undergone enhanced densification (U2), thick refrozen ice (U3), and advected continental ice (U4). We show that the OPTV-derived pattern of firn air content is consistent with previous estimates, but that a significant proportion of firn air is contained within U4, which we interpret to have been deposited inland of the grounding line. The structure of LCIS is strongly influenced by the E-W gradient in föhn-driven melting, with sites close to the Antarctic Peninsula being predominantly composed of refrozen ice. Melting is also substantial toward the ice shelf center with >40% of the overall imaged ice column being composed of refrozen ice. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf Ice Shelves University of St Andrews: Research Portal Antarctic Antarctic Peninsula Austral The Antarctic Journal of Geophysical Research: Earth Surface 122 5 1139 1153 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
topic |
Ice shelves Glaciology Antarctica |
spellingShingle |
Ice shelves Glaciology Antarctica Ashmore, David W. Hubbard, Bryn Luckman, Adrian Kulessa, Bernd Bevan, Suzanne Booth, Adam Munneke, Peter Kuipers O'Leary, Martin Sevestre, Heidi Holland, Paul R. Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing |
topic_facet |
Ice shelves Glaciology Antarctica |
description |
We use borehole optical televiewing (OPTV) to explore the internal structure of Larsen C Ice Shelf (LCIS). We report a suite of five ~90 m long OPTV logs, recording a light-emitting diode-illuminated, geometrically correct image of the borehole wall, from the northern and central sectors of LCIS collected during austral spring 2014 and 2015. We use a thresholding-based technique to estimate the refrozen ice content of the ice column and exploit a recently calibrated density-luminosity relationship to reveal its structure. All sites are dense and strongly influenced by surface melt, with frequent refrozen ice layers and mean densities, between the depths of 1.87 and 90 m, ranging from 862 to 894 kg m −3 . We define four distinct units that comprise LCIS and relate these to ice provenance, dynamic history, and past melt events. These units are in situ meteoric ice with infiltration ice (U1), meteoric ice which has undergone enhanced densification (U2), thick refrozen ice (U3), and advected continental ice (U4). We show that the OPTV-derived pattern of firn air content is consistent with previous estimates, but that a significant proportion of firn air is contained within U4, which we interpret to have been deposited inland of the grounding line. The structure of LCIS is strongly influenced by the E-W gradient in föhn-driven melting, with sites close to the Antarctic Peninsula being predominantly composed of refrozen ice. Melting is also substantial toward the ice shelf center with >40% of the overall imaged ice column being composed of refrozen ice. |
format |
Article in Journal/Newspaper |
author |
Ashmore, David W. Hubbard, Bryn Luckman, Adrian Kulessa, Bernd Bevan, Suzanne Booth, Adam Munneke, Peter Kuipers O'Leary, Martin Sevestre, Heidi Holland, Paul R. |
author_facet |
Ashmore, David W. Hubbard, Bryn Luckman, Adrian Kulessa, Bernd Bevan, Suzanne Booth, Adam Munneke, Peter Kuipers O'Leary, Martin Sevestre, Heidi Holland, Paul R. |
author_sort |
Ashmore, David W. |
title |
Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing |
title_short |
Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing |
title_full |
Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing |
title_fullStr |
Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing |
title_full_unstemmed |
Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing |
title_sort |
ice and firn heterogeneity within larsen c ice shelf from borehole optical televiewing |
publishDate |
2017 |
url |
https://risweb.st-andrews.ac.uk/portal/en/researchoutput/ice-and-firn-heterogeneity-within-larsen-c-ice-shelf-from-borehole-optical-televiewing(cb91507b-2b5d-47df-98d5-ae2cb0ec5b9d).html https://doi.org/10.1002/2016JF004047 https://research-repository.st-andrews.ac.uk/bitstream/10023/10881/1/Sevestre_2017_JGRES_LarsenCIceShelf_CC.pdf |
geographic |
Antarctic Antarctic Peninsula Austral The Antarctic |
geographic_facet |
Antarctic Antarctic Peninsula Austral The Antarctic |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf Ice Shelves |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf Ice Shelves |
op_source |
Ashmore , D W , Hubbard , B , Luckman , A , Kulessa , B , Bevan , S , Booth , A , Munneke , P K , O'Leary , M , Sevestre , H & Holland , P R 2017 , ' Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing ' , Journal of Geophysical Research - Earth Surface , vol. 122 , no. 5 , pp. 1139-1153 . https://doi.org/10.1002/2016JF004047 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1002/2016JF004047 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
122 |
container_issue |
5 |
container_start_page |
1139 |
op_container_end_page |
1153 |
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1766119668137852928 |