Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing
The geometry of the sea floor immediately beyond Antarctica's marine-terminating glaciers is a fundamental control on warm-water routing, but it also describes former topographic pinning points that have been important for ice-shelf buttressing. Unfortunately, this information is often lacking...
Published in: | The Cryosphere |
---|---|
Main Authors: | , , , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2020
|
Subjects: | |
Online Access: | https://hdl.handle.net/1911/109566 https://doi.org/10.5194/tc-14-2883-2020 |
id |
ftriceuniv:oai:scholarship.rice.edu:1911/109566 |
---|---|
record_format |
openpolar |
spelling |
ftriceuniv:oai:scholarship.rice.edu:1911/109566 2023-05-15T13:44:56+02:00 Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing Hogan, Kelly A. Larter, Robert D. Graham, Alastair G.C. Arthern, Robert Kirkham, James D. Minzoni, Rebecca Totten Jordan, Tom A. Clark, Rachel Fitzgerald, Victoria Wåhlin, Anna K. Anderson, John B. Hillenbrand, Claus-Dieter Nitsche, Frank O. Simkins, Lauren Smith, James A. Gohl, Karsten Arndt, Jan Erik Hong, Jongkuk Wellner, Julia 2020 application/pdf https://hdl.handle.net/1911/109566 https://doi.org/10.5194/tc-14-2883-2020 eng eng Copernicus Publications Hogan, Kelly A., Larter, Robert D., Graham, Alastair G.C., et al. "Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing." The Cryosphere, 14, (2020) Copernicus Publications: 2883-2908. https://doi.org/10.5194/tc-14-2883-2020. https://hdl.handle.net/1911/109566 https://doi.org/10.5194/tc-14-2883-2020 This work is distributed under the Creative Commons Attribution 4.0 License. https://creativecommons.org/licenses/by/4.0/ CC-BY Journal article Text publisher version 2020 ftriceuniv https://doi.org/10.5194/tc-14-2883-2020 2022-08-09T20:34:11Z The geometry of the sea floor immediately beyond Antarctica's marine-terminating glaciers is a fundamental control on warm-water routing, but it also describes former topographic pinning points that have been important for ice-shelf buttressing. Unfortunately, this information is often lacking due to the inaccessibility of these areas for survey, leading to modelled or interpolated bathymetries being used as boundary conditions in numerical modelling simulations. At Thwaites Glacier (TG) this critical data gap was addressed in 2019 during the first cruise of the International Thwaites Glacier Collaboration (ITGC) project. We present more than 2000 km2 of new multibeam echo-sounder (MBES) data acquired in exceptional sea-ice conditions immediately offshore TG, and we update existing bathymetric compilations. The cross-sectional areas of sea-floor troughs are under-predicted by up to 40 % or are not resolved at all where MBES data are missing, suggesting that calculations of trough capacity, and thus oceanic heat flux, may be significantly underestimated. Spatial variations in the morphology of topographic highs, known to be former pinning points for the floating ice shelf of TG, indicate differences in bed composition that are supported by landform evidence. We discuss links to ice dynamics for an overriding ice mass including a potential positive feedback mechanism where erosion of soft erodible highs may lead to ice-shelf ungrounding even with little or no ice thinning. Analyses of bed roughnesses and basal drag contributions show that the sea-floor bathymetry in front of TG is an analogue for extant bed areas. Ice flow over the sea-floor troughs and ridges would have been affected by similarly high basal drag to that acting at the grounding zone today. We conclude that more can certainly be gleaned from these 3D bathymetric datasets regarding the likely spatial variability of bed roughness and bed composition types underneath TG. This work also addresses the requirements of recent numerical ice-sheet and ocean ... Article in Journal/Newspaper Antarc* Ice Sheet Ice Shelf Sea ice The Cryosphere Thwaites Glacier Rice University: Digital Scholarship Archive Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) The Cryosphere 14 9 2883 2908 |
institution |
Open Polar |
collection |
Rice University: Digital Scholarship Archive |
op_collection_id |
ftriceuniv |
language |
English |
description |
The geometry of the sea floor immediately beyond Antarctica's marine-terminating glaciers is a fundamental control on warm-water routing, but it also describes former topographic pinning points that have been important for ice-shelf buttressing. Unfortunately, this information is often lacking due to the inaccessibility of these areas for survey, leading to modelled or interpolated bathymetries being used as boundary conditions in numerical modelling simulations. At Thwaites Glacier (TG) this critical data gap was addressed in 2019 during the first cruise of the International Thwaites Glacier Collaboration (ITGC) project. We present more than 2000 km2 of new multibeam echo-sounder (MBES) data acquired in exceptional sea-ice conditions immediately offshore TG, and we update existing bathymetric compilations. The cross-sectional areas of sea-floor troughs are under-predicted by up to 40 % or are not resolved at all where MBES data are missing, suggesting that calculations of trough capacity, and thus oceanic heat flux, may be significantly underestimated. Spatial variations in the morphology of topographic highs, known to be former pinning points for the floating ice shelf of TG, indicate differences in bed composition that are supported by landform evidence. We discuss links to ice dynamics for an overriding ice mass including a potential positive feedback mechanism where erosion of soft erodible highs may lead to ice-shelf ungrounding even with little or no ice thinning. Analyses of bed roughnesses and basal drag contributions show that the sea-floor bathymetry in front of TG is an analogue for extant bed areas. Ice flow over the sea-floor troughs and ridges would have been affected by similarly high basal drag to that acting at the grounding zone today. We conclude that more can certainly be gleaned from these 3D bathymetric datasets regarding the likely spatial variability of bed roughness and bed composition types underneath TG. This work also addresses the requirements of recent numerical ice-sheet and ocean ... |
format |
Article in Journal/Newspaper |
author |
Hogan, Kelly A. Larter, Robert D. Graham, Alastair G.C. Arthern, Robert Kirkham, James D. Minzoni, Rebecca Totten Jordan, Tom A. Clark, Rachel Fitzgerald, Victoria Wåhlin, Anna K. Anderson, John B. Hillenbrand, Claus-Dieter Nitsche, Frank O. Simkins, Lauren Smith, James A. Gohl, Karsten Arndt, Jan Erik Hong, Jongkuk Wellner, Julia |
spellingShingle |
Hogan, Kelly A. Larter, Robert D. Graham, Alastair G.C. Arthern, Robert Kirkham, James D. Minzoni, Rebecca Totten Jordan, Tom A. Clark, Rachel Fitzgerald, Victoria Wåhlin, Anna K. Anderson, John B. Hillenbrand, Claus-Dieter Nitsche, Frank O. Simkins, Lauren Smith, James A. Gohl, Karsten Arndt, Jan Erik Hong, Jongkuk Wellner, Julia Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing |
author_facet |
Hogan, Kelly A. Larter, Robert D. Graham, Alastair G.C. Arthern, Robert Kirkham, James D. Minzoni, Rebecca Totten Jordan, Tom A. Clark, Rachel Fitzgerald, Victoria Wåhlin, Anna K. Anderson, John B. Hillenbrand, Claus-Dieter Nitsche, Frank O. Simkins, Lauren Smith, James A. Gohl, Karsten Arndt, Jan Erik Hong, Jongkuk Wellner, Julia |
author_sort |
Hogan, Kelly A. |
title |
Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing |
title_short |
Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing |
title_full |
Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing |
title_fullStr |
Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing |
title_full_unstemmed |
Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing |
title_sort |
revealing the former bed of thwaites glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://hdl.handle.net/1911/109566 https://doi.org/10.5194/tc-14-2883-2020 |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Thwaites Glacier |
geographic_facet |
Thwaites Glacier |
genre |
Antarc* Ice Sheet Ice Shelf Sea ice The Cryosphere Thwaites Glacier |
genre_facet |
Antarc* Ice Sheet Ice Shelf Sea ice The Cryosphere Thwaites Glacier |
op_relation |
Hogan, Kelly A., Larter, Robert D., Graham, Alastair G.C., et al. "Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: implications for warm-water routing and bed controls on ice flow and buttressing." The Cryosphere, 14, (2020) Copernicus Publications: 2883-2908. https://doi.org/10.5194/tc-14-2883-2020. https://hdl.handle.net/1911/109566 https://doi.org/10.5194/tc-14-2883-2020 |
op_rights |
This work is distributed under the Creative Commons Attribution 4.0 License. https://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/tc-14-2883-2020 |
container_title |
The Cryosphere |
container_volume |
14 |
container_issue |
9 |
container_start_page |
2883 |
op_container_end_page |
2908 |
_version_ |
1766208728977113088 |