Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset
The coastal bathymetry of Thwaites Glacier (TG) is poorly known yet nearshore sea-floor highs have the potential to act as pinning points for floating ice shelves, or to block warm water incursions to the grounding line. In contrast, deeper areas control warm water routing. Here, we present more tha...
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Online Access: | https://epic.awi.de/id/eprint/51867/ https://hdl.handle.net/10013/epic.e61dd4d1-5778-42df-aaeb-eac2ca20dd8a |
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ftawi:oai:epic.awi.de:51867 2024-09-15T17:42:19+00:00 Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset Hogan, Kelly Larter, Robert D. Graham, Alastair G. C. Arthern, Robert Kirkham, James Totten Minzoni, Rebecca Jordan, Tom Clark, Rachel Fitzgerald, Victoria Anderson, John B. Hillenbrand, Claus-Dieter Nitsche, Frank O. Simkins, Lauren Smith, James A. Gohl, Karsten Arndt, Jan Erik Hong, Jongkuk Wellner, Julia 2020 https://epic.awi.de/id/eprint/51867/ https://hdl.handle.net/10013/epic.e61dd4d1-5778-42df-aaeb-eac2ca20dd8a unknown Hogan, K. , Larter, R. D. , Graham, A. G. C. , Arthern, R. , Kirkham, J. , Totten Minzoni, R. , Jordan, T. , Clark, R. , Fitzgerald, V. , Anderson, J. B. , Hillenbrand, C. D. , Nitsche, F. O. , Simkins, L. , Smith, J. A. , Gohl, K. orcid:0000-0002-9558-2116 , Arndt, J. E. orcid:0000-0002-9413-1612 , Hong, J. and Wellner, J. (2020) Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset , EGU General Assembly, Online Conference, 4 May 2020 - 8 May 2020 . hdl:10013/epic.e61dd4d1-5778-42df-aaeb-eac2ca20dd8a EPIC3EGU General Assembly, Online Conference, 2020-05-04-2020-05-08 Conference notRev 2020 ftawi 2024-06-24T04:24:41Z The coastal bathymetry of Thwaites Glacier (TG) is poorly known yet nearshore sea-floor highs have the potential to act as pinning points for floating ice shelves, or to block warm water incursions to the grounding line. In contrast, deeper areas control warm water routing. Here, we present more than 2000 km2 of new multibeam echo-sounder data (MBES) acquired offshore TG during the first cruise of the International Thwaites Glacier Collaboration (ITGC) project on the RV/IB Nathaniel B. Palmer (NBP19-02) in February-March 2019. Beyond TG, the bathymetry is dominated by a >1200 m deep, structurally-controlled trough and discontinuous ridge, on which the Eastern Ice Shelf is pinned. The geometry and composition of the ridge varies spatially with some sea-floor highs having distinctive flat-topped morphologies produced as their tops were planed-off by erosion at the base of the seaward-moving Thwaites Ice Shelf. In addition, submarine landform evidence indicates at least some unconsolidated sediment cover on the highs, as well as in the troughs that separate them. Knowing that this offshore area of ridges and troughs is a former bed for TG, we also used a novel spectral approach and existing ice-flow theory to investigate bed roughness and basal drag over the newly-revealed offshore topography. We show that the sea-floor bathymetry is a good analogue for extant bed areas of TG and that ice-sheet retreat over the sea-floor troughs and ridges would have been affected by high basal drag similar to that acting in the grounding zone today. Comparisons of the new MBES data with existing regional compilations show that high-frequency (finer than 5 km) bathymetric variability beyond Antarctic ice shelves can only be resolved by observations such as MBES and that without these data calculations of the oceanic heat flux may be significantly underestimated. This work supports the findings of recent numerical ice-sheet and ocean modelling studies that recognise the need for accurate and high-resolution bathymetry to ... Conference Object Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Thwaites Glacier Thwaites Ice Shelf Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
institution |
Open Polar |
collection |
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
The coastal bathymetry of Thwaites Glacier (TG) is poorly known yet nearshore sea-floor highs have the potential to act as pinning points for floating ice shelves, or to block warm water incursions to the grounding line. In contrast, deeper areas control warm water routing. Here, we present more than 2000 km2 of new multibeam echo-sounder data (MBES) acquired offshore TG during the first cruise of the International Thwaites Glacier Collaboration (ITGC) project on the RV/IB Nathaniel B. Palmer (NBP19-02) in February-March 2019. Beyond TG, the bathymetry is dominated by a >1200 m deep, structurally-controlled trough and discontinuous ridge, on which the Eastern Ice Shelf is pinned. The geometry and composition of the ridge varies spatially with some sea-floor highs having distinctive flat-topped morphologies produced as their tops were planed-off by erosion at the base of the seaward-moving Thwaites Ice Shelf. In addition, submarine landform evidence indicates at least some unconsolidated sediment cover on the highs, as well as in the troughs that separate them. Knowing that this offshore area of ridges and troughs is a former bed for TG, we also used a novel spectral approach and existing ice-flow theory to investigate bed roughness and basal drag over the newly-revealed offshore topography. We show that the sea-floor bathymetry is a good analogue for extant bed areas of TG and that ice-sheet retreat over the sea-floor troughs and ridges would have been affected by high basal drag similar to that acting in the grounding zone today. Comparisons of the new MBES data with existing regional compilations show that high-frequency (finer than 5 km) bathymetric variability beyond Antarctic ice shelves can only be resolved by observations such as MBES and that without these data calculations of the oceanic heat flux may be significantly underestimated. This work supports the findings of recent numerical ice-sheet and ocean modelling studies that recognise the need for accurate and high-resolution bathymetry to ... |
format |
Conference Object |
author |
Hogan, Kelly Larter, Robert D. Graham, Alastair G. C. Arthern, Robert Kirkham, James Totten Minzoni, Rebecca Jordan, Tom Clark, Rachel Fitzgerald, Victoria 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 Larter, Robert D. Graham, Alastair G. C. Arthern, Robert Kirkham, James Totten Minzoni, Rebecca Jordan, Tom Clark, Rachel Fitzgerald, Victoria Anderson, John B. Hillenbrand, Claus-Dieter Nitsche, Frank O. Simkins, Lauren Smith, James A. Gohl, Karsten Arndt, Jan Erik Hong, Jongkuk Wellner, Julia Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset |
author_facet |
Hogan, Kelly Larter, Robert D. Graham, Alastair G. C. Arthern, Robert Kirkham, James Totten Minzoni, Rebecca Jordan, Tom Clark, Rachel Fitzgerald, Victoria 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 |
title |
Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset |
title_short |
Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset |
title_full |
Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset |
title_fullStr |
Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset |
title_full_unstemmed |
Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset |
title_sort |
lessons learnt from the former bed of thwaites glacier: a new multibeam-bathymetric dataset |
publishDate |
2020 |
url |
https://epic.awi.de/id/eprint/51867/ https://hdl.handle.net/10013/epic.e61dd4d1-5778-42df-aaeb-eac2ca20dd8a |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Thwaites Glacier Thwaites Ice Shelf |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Thwaites Glacier Thwaites Ice Shelf |
op_source |
EPIC3EGU General Assembly, Online Conference, 2020-05-04-2020-05-08 |
op_relation |
Hogan, K. , Larter, R. D. , Graham, A. G. C. , Arthern, R. , Kirkham, J. , Totten Minzoni, R. , Jordan, T. , Clark, R. , Fitzgerald, V. , Anderson, J. B. , Hillenbrand, C. D. , Nitsche, F. O. , Simkins, L. , Smith, J. A. , Gohl, K. orcid:0000-0002-9558-2116 , Arndt, J. E. orcid:0000-0002-9413-1612 , Hong, J. and Wellner, J. (2020) Lessons learnt from the former bed of Thwaites Glacier: a new multibeam-bathymetric dataset , EGU General Assembly, Online Conference, 4 May 2020 - 8 May 2020 . hdl:10013/epic.e61dd4d1-5778-42df-aaeb-eac2ca20dd8a |
_version_ |
1810488848763846656 |