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...
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ftunivutrecht:oai:dspace.library.uu.nl:1874/370812 2023-07-23T04:15:48+02:00 Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing Ashmore, David Hubbard, Bryn Luckman, A. Kulessa, Bernd Bevan, S. Booth, Adam Kuipers Munneke, P. O'Leary, Martin Sevestre, Heidi Holland, Paul R. Sub Dynamics Meteorology Marine and Atmospheric Research 2017-05 image/pdf https://dspace.library.uu.nl/handle/1874/370812 en eng 2169-9003 https://dspace.library.uu.nl/handle/1874/370812 info:eu-repo/semantics/OpenAccess ice shelves Antarctica glaciology Article 2017 ftunivutrecht 2023-07-02T02:32:28Z 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 Utrecht University Repository Antarctic Antarctic Peninsula Austral The Antarctic |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
ice shelves Antarctica glaciology |
spellingShingle |
ice shelves Antarctica glaciology Ashmore, David Hubbard, Bryn Luckman, A. Kulessa, Bernd Bevan, S. Booth, Adam Kuipers Munneke, P. 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 Antarctica glaciology |
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. |
author2 |
Sub Dynamics Meteorology Marine and Atmospheric Research |
format |
Article in Journal/Newspaper |
author |
Ashmore, David Hubbard, Bryn Luckman, A. Kulessa, Bernd Bevan, S. Booth, Adam Kuipers Munneke, P. O'Leary, Martin Sevestre, Heidi Holland, Paul R. |
author_facet |
Ashmore, David Hubbard, Bryn Luckman, A. Kulessa, Bernd Bevan, S. Booth, Adam Kuipers Munneke, P. O'Leary, Martin Sevestre, Heidi Holland, Paul R. |
author_sort |
Ashmore, David |
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://dspace.library.uu.nl/handle/1874/370812 |
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_relation |
2169-9003 https://dspace.library.uu.nl/handle/1874/370812 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1772176827778859008 |