Marine Ice Cliff Instability Mitigated by Slow Removal of Ice Shelves
©2019. American Geophysical Union. All Rights Reserved. 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, init...
Main Authors: | , , |
---|---|
Other Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Geophysical Union (AGU)
2021
|
Subjects: | |
Online Access: | https://hdl.handle.net/1721.1/133824.2 |
id |
ftmit:oai:dspace.mit.edu:1721.1/133824.2 |
---|---|
record_format |
openpolar |
spelling |
ftmit:oai:dspace.mit.edu:1721.1/133824.2 2023-06-11T04:05:55+02:00 Marine Ice Cliff Instability Mitigated by Slow Removal of Ice Shelves Clerc, Fiona Minchew, Brent M Behn, Mark D Joint Program in Applied Ocean Physics and Engineering Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences 2021-09-17T15:25:15Z application/octet-stream https://hdl.handle.net/1721.1/133824.2 en eng American Geophysical Union (AGU) 10.1029/2019GL084183 Geophysical Research Letters https://hdl.handle.net/1721.1/133824.2 Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ MIT web domain Article http://purl.org/eprint/type/JournalArticle 2021 ftmit 2023-05-29T08:33:01Z ©2019. American Geophysical Union. All Rights Reserved. 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. NSF (Awards OPP-1739031 and EAR-19- 283 03897) Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves DSpace@MIT (Massachusetts Institute of Technology) Antarctic The Antarctic |
institution |
Open Polar |
collection |
DSpace@MIT (Massachusetts Institute of Technology) |
op_collection_id |
ftmit |
language |
English |
description |
©2019. American Geophysical Union. All Rights Reserved. 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. NSF (Awards OPP-1739031 and EAR-19- 283 03897) |
author2 |
Joint Program in Applied Ocean Physics and Engineering Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
format |
Article in Journal/Newspaper |
author |
Clerc, Fiona Minchew, Brent M Behn, Mark D |
spellingShingle |
Clerc, Fiona Minchew, Brent M Behn, Mark D Marine Ice Cliff Instability Mitigated by Slow Removal of Ice Shelves |
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 (AGU) |
publishDate |
2021 |
url |
https://hdl.handle.net/1721.1/133824.2 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves |
op_source |
MIT web domain |
op_relation |
10.1029/2019GL084183 Geophysical Research Letters https://hdl.handle.net/1721.1/133824.2 |
op_rights |
Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ |
_version_ |
1768377598447976448 |