Marine ice cliff instability mitigated by slow removal of ice shelves
Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46, (2019): 12108-12116, doi:10.1029/2019GL084183. The accelerate...
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Online Access: | https://hdl.handle.net/1912/25343 |
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/25343 2023-05-15T13:48:31+02:00 Marine ice cliff instability mitigated by slow removal of ice shelves Clerc, Fiona Minchew, Brent M. Behn, Mark D. 2019-10-21 https://hdl.handle.net/1912/25343 unknown American Geophysical Union https://doi.org/10.1029/2019GL084183 Clerc, F., Minchew, B. M., & Behn, M. D. (2019). Marine ice cliff instability mitigated by slow removal of ice shelves. Geophysical Research Letters, 46, 12108-12116. https://hdl.handle.net/1912/25343 doi:10.1029/2019GL084183 Clerc, F., Minchew, B. M., & Behn, M. D. (2019). Marine ice cliff instability mitigated by slow removal of ice shelves. Geophysical Research Letters, 46, 12108-12116. doi:10.1029/2019GL084183 Marine ice cliff Buttressing ice shelf Antarctic Ice Sheet Ice‐shelf collapse Brittle‐ductile transition Marine ice cliff instability Article 2019 ftwhoas https://doi.org/10.1029/2019GL084183 2022-10-29T22:57:17Z Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46, (2019): 12108-12116, doi:10.1029/2019GL084183. The accelerated calving of ice shelves buttressing the Antarctic Ice Sheet may form unstable ice cliffs. The marine ice cliff instability hypothesis posits that cliffs taller than a critical height (~90 m) will undergo structural collapse, initiating runaway retreat in ice‐sheet models. This critical height is based on inferences from preexisting, static ice cliffs. Here we show how the critical height increases with the timescale of ice‐shelf collapse. We model failure mechanisms within an ice cliff deforming after removal of ice‐shelf buttressing stresses. If removal occurs rapidly, the cliff deforms primarily elastically and fails through tensile‐brittle fracture, even at relatively small cliff heights. As the ice‐shelf removal timescale increases, viscous relaxation dominates, and the critical height increases to ~540 m for timescales greater than days. A 90‐m critical height implies ice‐shelf removal in under an hour. Incorporation of ice‐shelf collapse timescales in prognostic ice‐sheet models will mitigate the marine ice cliff instability, implying less ice mass loss. We thank Greg Hirth, Brad Hager, and Bill Durham for their useful comments. The manuscript benefited from constructive reviews by Dan Martin and an anonymous reviewer and editorial handling by Mathieu Morlighem. This work was supported by an NSF‐GRFP (Fiona Clerc), and NSF Awards OPP‐1739031 (Brent Minchew) and EAR‐19‐03897 (Mark Behn). Code reproducing our results is found at this address (https://doi.org/10.5281/zenodo.3379074). 2020-04-21 Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Antarctic Behn ENVELOPE(-61.433,-61.433,-64.383,-64.383) Hager ENVELOPE(162.800,162.800,-70.883,-70.883) Mathieu ENVELOPE(136.814,136.814,-66.331,-66.331) The Antarctic Geophysical Research Letters 46 21 12108 12116 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
unknown |
topic |
Marine ice cliff Buttressing ice shelf Antarctic Ice Sheet Ice‐shelf collapse Brittle‐ductile transition Marine ice cliff instability |
spellingShingle |
Marine ice cliff Buttressing ice shelf Antarctic Ice Sheet Ice‐shelf collapse Brittle‐ductile transition Marine ice cliff instability Clerc, Fiona Minchew, Brent M. Behn, Mark D. Marine ice cliff instability mitigated by slow removal of ice shelves |
topic_facet |
Marine ice cliff Buttressing ice shelf Antarctic Ice Sheet Ice‐shelf collapse Brittle‐ductile transition Marine ice cliff instability |
description |
Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46, (2019): 12108-12116, doi:10.1029/2019GL084183. The accelerated calving of ice shelves buttressing the Antarctic Ice Sheet may form unstable ice cliffs. The marine ice cliff instability hypothesis posits that cliffs taller than a critical height (~90 m) will undergo structural collapse, initiating runaway retreat in ice‐sheet models. This critical height is based on inferences from preexisting, static ice cliffs. Here we show how the critical height increases with the timescale of ice‐shelf collapse. We model failure mechanisms within an ice cliff deforming after removal of ice‐shelf buttressing stresses. If removal occurs rapidly, the cliff deforms primarily elastically and fails through tensile‐brittle fracture, even at relatively small cliff heights. As the ice‐shelf removal timescale increases, viscous relaxation dominates, and the critical height increases to ~540 m for timescales greater than days. A 90‐m critical height implies ice‐shelf removal in under an hour. Incorporation of ice‐shelf collapse timescales in prognostic ice‐sheet models will mitigate the marine ice cliff instability, implying less ice mass loss. We thank Greg Hirth, Brad Hager, and Bill Durham for their useful comments. The manuscript benefited from constructive reviews by Dan Martin and an anonymous reviewer and editorial handling by Mathieu Morlighem. This work was supported by an NSF‐GRFP (Fiona Clerc), and NSF Awards OPP‐1739031 (Brent Minchew) and EAR‐19‐03897 (Mark Behn). Code reproducing our results is found at this address (https://doi.org/10.5281/zenodo.3379074). 2020-04-21 |
format |
Article in Journal/Newspaper |
author |
Clerc, Fiona Minchew, Brent M. Behn, Mark D. |
author_facet |
Clerc, Fiona Minchew, Brent M. Behn, Mark D. |
author_sort |
Clerc, Fiona |
title |
Marine ice cliff instability mitigated by slow removal of ice shelves |
title_short |
Marine ice cliff instability mitigated by slow removal of ice shelves |
title_full |
Marine ice cliff instability mitigated by slow removal of ice shelves |
title_fullStr |
Marine ice cliff instability mitigated by slow removal of ice shelves |
title_full_unstemmed |
Marine ice cliff instability mitigated by slow removal of ice shelves |
title_sort |
marine ice cliff instability mitigated by slow removal of ice shelves |
publisher |
American Geophysical Union |
publishDate |
2019 |
url |
https://hdl.handle.net/1912/25343 |
long_lat |
ENVELOPE(-61.433,-61.433,-64.383,-64.383) ENVELOPE(162.800,162.800,-70.883,-70.883) ENVELOPE(136.814,136.814,-66.331,-66.331) |
geographic |
Antarctic Behn Hager Mathieu The Antarctic |
geographic_facet |
Antarctic Behn Hager Mathieu The Antarctic |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves |
op_source |
Clerc, F., Minchew, B. M., & Behn, M. D. (2019). Marine ice cliff instability mitigated by slow removal of ice shelves. Geophysical Research Letters, 46, 12108-12116. doi:10.1029/2019GL084183 |
op_relation |
https://doi.org/10.1029/2019GL084183 Clerc, F., Minchew, B. M., & Behn, M. D. (2019). Marine ice cliff instability mitigated by slow removal of ice shelves. Geophysical Research Letters, 46, 12108-12116. https://hdl.handle.net/1912/25343 doi:10.1029/2019GL084183 |
op_doi |
https://doi.org/10.1029/2019GL084183 |
container_title |
Geophysical Research Letters |
container_volume |
46 |
container_issue |
21 |
container_start_page |
12108 |
op_container_end_page |
12116 |
_version_ |
1766249381977128960 |