Derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of Thwaites Glacier
Determining the future evolution of the Antarctic Ice Sheet is critical for understanding and narrowing the large existing uncertainties in century-scale global mean sea-level-rise (SLR) projections. One of the most significant glaciers and ice streams in Antarctica, Thwaites Glacier, is at risk of...
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2022
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ftdoajarticles:oai:doaj.org/article:5fac0523654c455a91764f3ec85d1607 2023-05-15T13:40:39+02:00 Derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of Thwaites Glacier B. A. Castleman N.-J. Schlegel L. Caron E. Larour A. Khazendar 2022-03-01T00:00:00Z https://doi.org/10.5194/tc-16-761-2022 https://doaj.org/article/5fac0523654c455a91764f3ec85d1607 EN eng Copernicus Publications https://tc.copernicus.org/articles/16/761/2022/tc-16-761-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-761-2022 1994-0416 1994-0424 https://doaj.org/article/5fac0523654c455a91764f3ec85d1607 The Cryosphere, Vol 16, Pp 761-778 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-761-2022 2022-12-31T12:58:09Z Determining the future evolution of the Antarctic Ice Sheet is critical for understanding and narrowing the large existing uncertainties in century-scale global mean sea-level-rise (SLR) projections. One of the most significant glaciers and ice streams in Antarctica, Thwaites Glacier, is at risk of destabilization and, if destabilized, has the potential to be the largest regional-scale contributor of SLR on Earth. This is because Thwaites Glacier is vulnerable to the marine ice-sheet instability as its grounding line is significantly influenced by ocean-driven basal melting rates, and its bedrock topography retrogrades into kilometer-deep troughs. In this study, we investigate how bedrock topography features influence the grounding line migration beneath Thwaites Glacier when extreme ocean-driven basal melt rates are applied. Specifically, we design experiments using the Ice-sheet and Sea-level System Model (ISSM) to quantify the SLR projection uncertainty due to reported errors in the current bedrock topography maps that are often used by ice-sheet models. We find that spread in model estimates of sea-level-rise contribution from Thwaites Glacier due to the reported bedrock topography error could be as large as 21.9 cm after 200 years of extreme ocean warming. Next, we perturb the bedrock topography beneath Thwaites Glacier using wavelet decomposition techniques to introduce realistic noise (within error). We explore the model space with multiple realizations of noise to quantify what spatial and vertical resolutions in bedrock topography are required to minimize the uncertainty in our 200-year experiment. We conclude that at least a 2 km spatial and 8 m vertical resolution would independently constrain possible SLR to ±2 cm over 200 years, fulfilling requirements outlined by the 2017 Decadal Survey for Earth Science. Lastly, we perform an ensemble of simulations to determine in which regions our model of Thwaites Glacier is most sensitive to perturbations in bedrock topography. Our results suggest that the ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet The Cryosphere Thwaites Glacier Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) The Cryosphere 16 3 761 778 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 B. A. Castleman N.-J. Schlegel L. Caron E. Larour A. Khazendar Derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of Thwaites Glacier |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Determining the future evolution of the Antarctic Ice Sheet is critical for understanding and narrowing the large existing uncertainties in century-scale global mean sea-level-rise (SLR) projections. One of the most significant glaciers and ice streams in Antarctica, Thwaites Glacier, is at risk of destabilization and, if destabilized, has the potential to be the largest regional-scale contributor of SLR on Earth. This is because Thwaites Glacier is vulnerable to the marine ice-sheet instability as its grounding line is significantly influenced by ocean-driven basal melting rates, and its bedrock topography retrogrades into kilometer-deep troughs. In this study, we investigate how bedrock topography features influence the grounding line migration beneath Thwaites Glacier when extreme ocean-driven basal melt rates are applied. Specifically, we design experiments using the Ice-sheet and Sea-level System Model (ISSM) to quantify the SLR projection uncertainty due to reported errors in the current bedrock topography maps that are often used by ice-sheet models. We find that spread in model estimates of sea-level-rise contribution from Thwaites Glacier due to the reported bedrock topography error could be as large as 21.9 cm after 200 years of extreme ocean warming. Next, we perturb the bedrock topography beneath Thwaites Glacier using wavelet decomposition techniques to introduce realistic noise (within error). We explore the model space with multiple realizations of noise to quantify what spatial and vertical resolutions in bedrock topography are required to minimize the uncertainty in our 200-year experiment. We conclude that at least a 2 km spatial and 8 m vertical resolution would independently constrain possible SLR to ±2 cm over 200 years, fulfilling requirements outlined by the 2017 Decadal Survey for Earth Science. Lastly, we perform an ensemble of simulations to determine in which regions our model of Thwaites Glacier is most sensitive to perturbations in bedrock topography. Our results suggest that the ... |
format |
Article in Journal/Newspaper |
author |
B. A. Castleman N.-J. Schlegel L. Caron E. Larour A. Khazendar |
author_facet |
B. A. Castleman N.-J. Schlegel L. Caron E. Larour A. Khazendar |
author_sort |
B. A. Castleman |
title |
Derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of Thwaites Glacier |
title_short |
Derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of Thwaites Glacier |
title_full |
Derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of Thwaites Glacier |
title_fullStr |
Derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of Thwaites Glacier |
title_full_unstemmed |
Derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of Thwaites Glacier |
title_sort |
derivation of bedrock topography measurement requirements for the reduction of uncertainty in ice-sheet model projections of thwaites glacier |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-761-2022 https://doaj.org/article/5fac0523654c455a91764f3ec85d1607 |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Antarctic The Antarctic Thwaites Glacier |
geographic_facet |
Antarctic The Antarctic Thwaites Glacier |
genre |
Antarc* Antarctic Antarctica Ice Sheet The Cryosphere Thwaites Glacier |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet The Cryosphere Thwaites Glacier |
op_source |
The Cryosphere, Vol 16, Pp 761-778 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/761/2022/tc-16-761-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-761-2022 1994-0416 1994-0424 https://doaj.org/article/5fac0523654c455a91764f3ec85d1607 |
op_doi |
https://doi.org/10.5194/tc-16-761-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
3 |
container_start_page |
761 |
op_container_end_page |
778 |
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1766138007998431232 |