Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica

SCHLEGEL, REBECCA

doi:10.23889/SUthesis.60072

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Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica / REBECCA SCHLEGEL

Swansea University Author: REBECCA SCHLEGEL

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DOI (Published version): 10.23889/SUthesis.60072

Abstract

Outlet glaciers and ice streams of the Antarctic Ice Sheet provide dis-charge pathways, transporting >90% of the continents ice into the oceans. Elongated landforms beneath fast ﬂowing ice streams form as a result of ice-bed interactions. Understanding their link to ice ﬂow dynamics will better i...

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Published:	Swansea 2022
Institution:	Swansea University
Degree level:	Doctoral
Degree name:	Ph.D
Supervisor:	Murray, Tavi
URI:	https://cronfa.swan.ac.uk/Record/cronfa60072
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first_indexed	2022-05-24T11:33:44Z
last_indexed	2022-05-25T03:36:51Z
id	cronfa60072
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spelling	2022-05-24T13:22:47.3579716 v2 60072 2022-05-24 Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica cc51dcdea873572890ef0435a4ef78de REBECCA SCHLEGEL REBECCA SCHLEGEL true false 2022-05-24 Outlet glaciers and ice streams of the Antarctic Ice Sheet provide dis-charge pathways, transporting >90% of the continents ice into the oceans. Elongated landforms beneath fast ﬂowing ice streams form as a result of ice-bed interactions. Understanding their link to ice ﬂow dynamics will better inform subglacial processes and allow these processes to be correctly implemented in predictive numerical ﬂow models, thus improving predictions of future contributions to sea level rise. In this thesis, a section of the bed of Rutford Ice Stream (West Antarctica), containing numerous elongated subglacial landforms, was analysed using a suite of 2D and 3D radar data with repeat surveys. Bed properties vary spatially over a 100 m scale and imply the pat-tern of inferred basal motion in this area is more complex, and basal sliding dominated areas are more extensive, than previously assumed. Local erosion rates are high (1 m/a), indicating a mobile bed, whereas most of the bed shows no temporal change, implying stability of the basal environment. Observations of landforms shortening, and previ-ous observations of landforms extending, highlight that landforms are a non-static part of the bed. Isolated landforms appear to consist of a more rigid sediment at their upstream end with softer sediment down-stream. Some landforms contain a water body (up to 10 km length) along their crest. 3D processed data reveal a so far unseen moat (de-pression) around one landform. Dimensions of the upstream part of the moat are comparable to dimensions of the upstream end of the landform (<50 m height, <300 m width). Observations suggest land-forms are depositional features, while the moat was likely eroded. The radar and other data analysed provide detailed landform and moat ar-chitecture, at a resolution comparable to digital elevation models of deglaciated terrain, and together with interpreted properties give a solid basis for testing existing landform formation theories. E-Thesis Swansea Subglacial landforms, geophysics, radar, seismics, bed properties, ice dynamics, West Antarctica, 3D migration 18 5 2022 2022-05-18 10.23889/SUthesis.60072 ORCiD identifier: https://orcid.org/0000-0003-1149-2816 COLLEGE NANME COLLEGE CODE Swansea University Murray, Tavi Doctoral Ph.D NERC; Research grant number: NE/G013187/1 2022-05-24T13:22:47.3579716 2022-05-24T12:30:12.8042532 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Geography REBECCA SCHLEGEL 1 60072__24166__b7a391b887bc4e24a7afe9e360c4b7fb.pdf Schlegel_Rebecca_PhD_Thesis_Final _Redacted_Signature.pdf 2022-05-24T13:22:29.2282432 Output 13591447 application/pdf E-Thesis – open access true Copyright: The author, Rebecca Schlegel, 2022. true eng
title	Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica
spellingShingle	Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica REBECCA SCHLEGEL
title_short	Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica
title_full	Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica
title_fullStr	Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica
title_full_unstemmed	Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica
title_sort	Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica
author_id_str_mv	cc51dcdea873572890ef0435a4ef78de
author_id_fullname_str_mv	cc51dcdea873572890ef0435a4ef78de_***_REBECCA SCHLEGEL
author	REBECCA SCHLEGEL
author2	REBECCA SCHLEGEL
format	E-Thesis
publishDate	2022
institution	Swansea University
doi_str_mv	10.23889/SUthesis.60072
college_str	Faculty of Science and Engineering
hierarchytype
hierarchy_top_id	facultyofscienceandengineering
hierarchy_top_title	Faculty of Science and Engineering
hierarchy_parent_id	facultyofscienceandengineering
hierarchy_parent_title	Faculty of Science and Engineering
department_str	School of Biosciences, Geography and Physics - Geography{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Geography
document_store_str	1
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description	Outlet glaciers and ice streams of the Antarctic Ice Sheet provide dis-charge pathways, transporting >90% of the continents ice into the oceans. Elongated landforms beneath fast ﬂowing ice streams form as a result of ice-bed interactions. Understanding their link to ice ﬂow dynamics will better inform subglacial processes and allow these processes to be correctly implemented in predictive numerical ﬂow models, thus improving predictions of future contributions to sea level rise. In this thesis, a section of the bed of Rutford Ice Stream (West Antarctica), containing numerous elongated subglacial landforms, was analysed using a suite of 2D and 3D radar data with repeat surveys. Bed properties vary spatially over a 100 m scale and imply the pat-tern of inferred basal motion in this area is more complex, and basal sliding dominated areas are more extensive, than previously assumed. Local erosion rates are high (1 m/a), indicating a mobile bed, whereas most of the bed shows no temporal change, implying stability of the basal environment. Observations of landforms shortening, and previ-ous observations of landforms extending, highlight that landforms are a non-static part of the bed. Isolated landforms appear to consist of a more rigid sediment at their upstream end with softer sediment down-stream. Some landforms contain a water body (up to 10 km length) along their crest. 3D processed data reveal a so far unseen moat (de-pression) around one landform. Dimensions of the upstream part of the moat are comparable to dimensions of the upstream end of the landform (<50 m height, <300 m width). Observations suggest land-forms are depositional features, while the moat was likely eroded. The radar and other data analysed provide detailed landform and moat ar-chitecture, at a resolution comparable to digital elevation models of deglaciated terrain, and together with interpreted properties give a solid basis for testing existing landform formation theories.
published_date	2022-05-18T04:17:52Z
_version_	1763754191208054784
score	11.013148

Bed properties and three-dimensional topography from radar at Rutford Ice Stream, West Antarctica / REBECCA SCHLEGEL

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