Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf

<p>The Thwaites Eastern Ice Shelf (TEIS) buttresses the eastern grounded portion of Thwaites Glacier through contact with a pinning point at its seaward limit. Loss of this ice shelf will promote further acceleration of Thwaites Glacier. Understanding the dynamic controls and structural integr...

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Autores principales: K. E. Alley, C. T. Wild, A. Luckman, T. A. Scambos, M. Truffer, E. C. Pettit, A. Muto, B. Wallin, M. Klinger, T. Sutterley, S. F. Child, C. Hulen, J. T. M. Lenaerts, M. Maclennan, E. Keenan, D. Dunmire
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Publicado: Copernicus Publications 2021
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spelling oai:doaj.org-article:fb9d35adb3504645b195a11825bf78362021-11-22T15:12:14ZTwo decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf10.5194/tc-15-5187-20211994-04161994-0424https://doaj.org/article/fb9d35adb3504645b195a11825bf78362021-11-01T00:00:00Zhttps://tc.copernicus.org/articles/15/5187/2021/tc-15-5187-2021.pdfhttps://doaj.org/toc/1994-0416https://doaj.org/toc/1994-0424<p>The Thwaites Eastern Ice Shelf (TEIS) buttresses the eastern grounded portion of Thwaites Glacier through contact with a pinning point at its seaward limit. Loss of this ice shelf will promote further acceleration of Thwaites Glacier. Understanding the dynamic controls and structural integrity of the TEIS is therefore important to estimating Thwaites' future sea-level contribution. We present a <span class="inline-formula">∼</span> 20-year record of change on the TEIS that reveals the dynamic controls governing the ice shelf's past behaviour and ongoing evolution. We derived ice velocities from MODIS and Sentinel-1 image data using feature tracking and speckle tracking, respectively, and we combined these records with ITS_LIVE and GOLIVE velocity products from Landsat-7 and Landsat-8. In addition, we estimated surface lowering and basal melt rates using the Reference Elevation Model of Antarctica (REMA) DEM in comparison to ICESat and ICESat-2 altimetry. Early in the record, TEIS flow dynamics were strongly controlled by the neighbouring Thwaites Western Ice Tongue (TWIT). Flow patterns on the TEIS changed following the disintegration of the TWIT around 2008, with a new divergence in ice flow developing around the pinning point at its seaward limit. Simultaneously, the TEIS developed new rifting that extends from the shear zone upstream of the ice rise and increased strain concentration within this shear zone. As these horizontal changes occurred, sustained thinning driven by basal melt reduced ice thickness, particularly near the grounding line and in the shear zone area upstream of the pinning point. This evidence of weakening at a rapid pace suggests that the TEIS is likely to fully destabilize in the next few decades, leading to further acceleration of Thwaites Glacier.</p>K. E. AlleyC. T. WildA. LuckmanT. A. ScambosM. TrufferE. C. PettitA. MutoB. WallinM. KlingerT. SutterleyS. F. ChildC. HulenJ. T. M. LenaertsM. MaclennanE. KeenanD. DunmireCopernicus PublicationsarticleEnvironmental sciencesGE1-350GeologyQE1-996.5ENThe Cryosphere, Vol 15, Pp 5187-5203 (2021)
institution DOAJ
collection DOAJ
language EN
topic Environmental sciences
GE1-350
Geology
QE1-996.5
spellingShingle Environmental sciences
GE1-350
Geology
QE1-996.5
K. E. Alley
C. T. Wild
A. Luckman
T. A. Scambos
M. Truffer
E. C. Pettit
A. Muto
B. Wallin
M. Klinger
T. Sutterley
S. F. Child
C. Hulen
J. T. M. Lenaerts
M. Maclennan
E. Keenan
D. Dunmire
Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
description <p>The Thwaites Eastern Ice Shelf (TEIS) buttresses the eastern grounded portion of Thwaites Glacier through contact with a pinning point at its seaward limit. Loss of this ice shelf will promote further acceleration of Thwaites Glacier. Understanding the dynamic controls and structural integrity of the TEIS is therefore important to estimating Thwaites' future sea-level contribution. We present a <span class="inline-formula">∼</span> 20-year record of change on the TEIS that reveals the dynamic controls governing the ice shelf's past behaviour and ongoing evolution. We derived ice velocities from MODIS and Sentinel-1 image data using feature tracking and speckle tracking, respectively, and we combined these records with ITS_LIVE and GOLIVE velocity products from Landsat-7 and Landsat-8. In addition, we estimated surface lowering and basal melt rates using the Reference Elevation Model of Antarctica (REMA) DEM in comparison to ICESat and ICESat-2 altimetry. Early in the record, TEIS flow dynamics were strongly controlled by the neighbouring Thwaites Western Ice Tongue (TWIT). Flow patterns on the TEIS changed following the disintegration of the TWIT around 2008, with a new divergence in ice flow developing around the pinning point at its seaward limit. Simultaneously, the TEIS developed new rifting that extends from the shear zone upstream of the ice rise and increased strain concentration within this shear zone. As these horizontal changes occurred, sustained thinning driven by basal melt reduced ice thickness, particularly near the grounding line and in the shear zone area upstream of the pinning point. This evidence of weakening at a rapid pace suggests that the TEIS is likely to fully destabilize in the next few decades, leading to further acceleration of Thwaites Glacier.</p>
format article
author K. E. Alley
C. T. Wild
A. Luckman
T. A. Scambos
M. Truffer
E. C. Pettit
A. Muto
B. Wallin
M. Klinger
T. Sutterley
S. F. Child
C. Hulen
J. T. M. Lenaerts
M. Maclennan
E. Keenan
D. Dunmire
author_facet K. E. Alley
C. T. Wild
A. Luckman
T. A. Scambos
M. Truffer
E. C. Pettit
A. Muto
B. Wallin
M. Klinger
T. Sutterley
S. F. Child
C. Hulen
J. T. M. Lenaerts
M. Maclennan
E. Keenan
D. Dunmire
author_sort K. E. Alley
title Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
title_short Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
title_full Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
title_fullStr Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
title_full_unstemmed Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
title_sort two decades of dynamic change and progressive destabilization on the thwaites eastern ice shelf
publisher Copernicus Publications
publishDate 2021
url https://doaj.org/article/fb9d35adb3504645b195a11825bf7836
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