Dynamic changes on the Wilkins Ice Shelf during the 2006–2009 retreat derived from satellite observations
The vast ice shelves around Antarctica provide significant restraint to the outflow from adjacent tributary glaciers. This important buttressing effect became apparent in the last decades, when outlet glaciers accelerated considerably after several ice shelves were lost around the Antarctic Peninsul...
Published in: | The Cryosphere |
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2017
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00010159 2023-05-15T13:34:49+02:00 Dynamic changes on the Wilkins Ice Shelf during the 2006–2009 retreat derived from satellite observations Rankl, Melanie Fürst, Johannes Jakob Humbert, Angelika Braun, Matthias Holger 2017-05 electronic https://doi.org/10.5194/tc-11-1199-2017 https://noa.gwlb.de/receive/cop_mods_00010159 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00010116/tc-11-1199-2017.pdf https://tc.copernicus.org/articles/11/1199/2017/tc-11-1199-2017.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-11-1199-2017 https://noa.gwlb.de/receive/cop_mods_00010159 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00010116/tc-11-1199-2017.pdf https://tc.copernicus.org/articles/11/1199/2017/tc-11-1199-2017.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2017 ftnonlinearchiv https://doi.org/10.5194/tc-11-1199-2017 2022-02-08T22:57:12Z The vast ice shelves around Antarctica provide significant restraint to the outflow from adjacent tributary glaciers. This important buttressing effect became apparent in the last decades, when outlet glaciers accelerated considerably after several ice shelves were lost around the Antarctic Peninsula (AP). The present study aims to assess dynamic changes on the Wilkins Ice Shelf (WIS) during different stages of ice-front retreat and partial collapse between early 2008 and 2009. The total ice-shelf area lost in these events was 2135 ± 75 km2 ( ∼ 15 % of the ice-shelf area relative to 2007). Here, we use time series of synthetic aperture radar (SAR) satellite observations (1994–1996, 2006–2010) in order to derive variations in surface-flow speed from intensity-offset tracking. Spatial patterns of horizontal strain-rate, stress and stress-flow angle distributions are determined during different ice-front retreat stages. Prior to the final break up of an ice bridge in 2008, a strong speed up is observed, which is also discernible from other derived quantities. We identify areas that are important for buttressing and areas prone to fracturing using in-flow and first principal strain rates as well as principal stress components. Further propagation of fractures can be explained as the first principal components of strain rates and stresses exceed documented threshold values. Positive second principal stresses are another scale-free indicator for ice-shelf areas, where fractures preferentially open. Second principal strain rates are found to be insensitive to ice-front retreat or fracturing. Changes in stress-flow angles highlight similar areas as the in-flow strain rates but are difficult to interpret. Our study reveals the large potential of modern SAR satellite time series to better understand dynamic and structural changes during ice-shelf retreat but also points to uncertainties introduced by the methods applied. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf Ice Shelves The Cryosphere Wilkins Ice Shelf Niedersächsisches Online-Archiv NOA Antarctic The Antarctic Antarctic Peninsula Wilkins ENVELOPE(59.326,59.326,-67.248,-67.248) Wilkins Ice Shelf ENVELOPE(-72.500,-72.500,-70.416,-70.416) The Cryosphere 11 3 1199 1211 |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Rankl, Melanie Fürst, Johannes Jakob Humbert, Angelika Braun, Matthias Holger Dynamic changes on the Wilkins Ice Shelf during the 2006–2009 retreat derived from satellite observations |
topic_facet |
article Verlagsveröffentlichung |
description |
The vast ice shelves around Antarctica provide significant restraint to the outflow from adjacent tributary glaciers. This important buttressing effect became apparent in the last decades, when outlet glaciers accelerated considerably after several ice shelves were lost around the Antarctic Peninsula (AP). The present study aims to assess dynamic changes on the Wilkins Ice Shelf (WIS) during different stages of ice-front retreat and partial collapse between early 2008 and 2009. The total ice-shelf area lost in these events was 2135 ± 75 km2 ( ∼ 15 % of the ice-shelf area relative to 2007). Here, we use time series of synthetic aperture radar (SAR) satellite observations (1994–1996, 2006–2010) in order to derive variations in surface-flow speed from intensity-offset tracking. Spatial patterns of horizontal strain-rate, stress and stress-flow angle distributions are determined during different ice-front retreat stages. Prior to the final break up of an ice bridge in 2008, a strong speed up is observed, which is also discernible from other derived quantities. We identify areas that are important for buttressing and areas prone to fracturing using in-flow and first principal strain rates as well as principal stress components. Further propagation of fractures can be explained as the first principal components of strain rates and stresses exceed documented threshold values. Positive second principal stresses are another scale-free indicator for ice-shelf areas, where fractures preferentially open. Second principal strain rates are found to be insensitive to ice-front retreat or fracturing. Changes in stress-flow angles highlight similar areas as the in-flow strain rates but are difficult to interpret. Our study reveals the large potential of modern SAR satellite time series to better understand dynamic and structural changes during ice-shelf retreat but also points to uncertainties introduced by the methods applied. |
format |
Article in Journal/Newspaper |
author |
Rankl, Melanie Fürst, Johannes Jakob Humbert, Angelika Braun, Matthias Holger |
author_facet |
Rankl, Melanie Fürst, Johannes Jakob Humbert, Angelika Braun, Matthias Holger |
author_sort |
Rankl, Melanie |
title |
Dynamic changes on the Wilkins Ice Shelf during the 2006–2009 retreat derived from satellite observations |
title_short |
Dynamic changes on the Wilkins Ice Shelf during the 2006–2009 retreat derived from satellite observations |
title_full |
Dynamic changes on the Wilkins Ice Shelf during the 2006–2009 retreat derived from satellite observations |
title_fullStr |
Dynamic changes on the Wilkins Ice Shelf during the 2006–2009 retreat derived from satellite observations |
title_full_unstemmed |
Dynamic changes on the Wilkins Ice Shelf during the 2006–2009 retreat derived from satellite observations |
title_sort |
dynamic changes on the wilkins ice shelf during the 2006–2009 retreat derived from satellite observations |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/tc-11-1199-2017 https://noa.gwlb.de/receive/cop_mods_00010159 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00010116/tc-11-1199-2017.pdf https://tc.copernicus.org/articles/11/1199/2017/tc-11-1199-2017.pdf |
long_lat |
ENVELOPE(59.326,59.326,-67.248,-67.248) ENVELOPE(-72.500,-72.500,-70.416,-70.416) |
geographic |
Antarctic The Antarctic Antarctic Peninsula Wilkins Wilkins Ice Shelf |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula Wilkins Wilkins Ice Shelf |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf Ice Shelves The Cryosphere Wilkins Ice Shelf |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf Ice Shelves The Cryosphere Wilkins Ice Shelf |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-11-1199-2017 https://noa.gwlb.de/receive/cop_mods_00010159 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00010116/tc-11-1199-2017.pdf https://tc.copernicus.org/articles/11/1199/2017/tc-11-1199-2017.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-11-1199-2017 |
container_title |
The Cryosphere |
container_volume |
11 |
container_issue |
3 |
container_start_page |
1199 |
op_container_end_page |
1211 |
_version_ |
1766057926137479168 |