The Response of Antarctic Ice Streams to Tidal Forcing
The majority of the ice flowing from the Antarctic interior makes its way to the ocean through fast-flowing ice streams, or glaciers. Understanding what controls the speed of these streams is extremely important in predicting the overall response of ice sheets to changing climatic conditions, and he...
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University of Cambridge
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ftunivcam:oai:www.repository.cam.ac.uk:1810/342322 2024-01-21T10:01:07+01:00 The Response of Antarctic Ice Streams to Tidal Forcing Warburton, Katarzyna 2022-10-21T14:12:34Z application/pdf https://www.repository.cam.ac.uk/handle/1810/342322 https://doi.org/10.17863/CAM.89743 eng eng University of Cambridge https://www.repository.cam.ac.uk/handle/1810/342322 doi:10.17863/CAM.89743 Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/ Fluid dynamics Ice sheets Thesis Doctoral Doctor of Philosophy (PhD) 2022 ftunivcam https://doi.org/10.17863/CAM.89743 2023-12-28T23:20:31Z The majority of the ice flowing from the Antarctic interior makes its way to the ocean through fast-flowing ice streams, or glaciers. Understanding what controls the speed of these streams is extremely important in predicting the overall response of ice sheets to changing climatic conditions, and hence in predicting future sea-level rise. A major factor determining the flux of grounded ice towards the ocean is the rate at which the ice slides over its bed, which is sensitive to conditions at the base of the ice such as shear stress and water pressure, and the material making up the bed. However, it remains difficult to measure and predict the evolution of these variables over the scale of ice sheets, and to accurately model their effect on sliding speed. In this thesis, I present novel methods to constrain and model the basal dynamics of ice, particularly motivated by observations of tidally-driven acceleration of Antarctic glaciers. In the first chapter, I review recent observations of spatial and temporal variability in ice velocity, existing simplified models of the flow of Antarctic ice streams, and sources of uncertainty in projections of ice-sheet mass loss. In the next section of the thesis I explore the link between ocean forcing and the water pressure beneath the grounded ice, by considering subglacial water transport at a tidally migrating grounding line. In chapter 2, I develop a model for the retention of water in the subglacial environment during the receding tide. This problem constitutes an elastic analogue to the Landau-Levich problem, where the thickness of the deposited fluid layer depends on the elasticity of the overlying sheet. I contrast the slow dynamics of the outgoing tide with the relatively fast dynamics of water entering the subglacial cavity during the incoming tide in chapter 3. This results in a non-linear filter between the ocean tides and the water pressure below the upstream ice sheet. In chapter 4, I develop a model for the deformation of subglacial sediment subject to these ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Ice Sheet Apollo - University of Cambridge Repository Antarctic The Antarctic |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Fluid dynamics Ice sheets |
spellingShingle |
Fluid dynamics Ice sheets Warburton, Katarzyna The Response of Antarctic Ice Streams to Tidal Forcing |
topic_facet |
Fluid dynamics Ice sheets |
description |
The majority of the ice flowing from the Antarctic interior makes its way to the ocean through fast-flowing ice streams, or glaciers. Understanding what controls the speed of these streams is extremely important in predicting the overall response of ice sheets to changing climatic conditions, and hence in predicting future sea-level rise. A major factor determining the flux of grounded ice towards the ocean is the rate at which the ice slides over its bed, which is sensitive to conditions at the base of the ice such as shear stress and water pressure, and the material making up the bed. However, it remains difficult to measure and predict the evolution of these variables over the scale of ice sheets, and to accurately model their effect on sliding speed. In this thesis, I present novel methods to constrain and model the basal dynamics of ice, particularly motivated by observations of tidally-driven acceleration of Antarctic glaciers. In the first chapter, I review recent observations of spatial and temporal variability in ice velocity, existing simplified models of the flow of Antarctic ice streams, and sources of uncertainty in projections of ice-sheet mass loss. In the next section of the thesis I explore the link between ocean forcing and the water pressure beneath the grounded ice, by considering subglacial water transport at a tidally migrating grounding line. In chapter 2, I develop a model for the retention of water in the subglacial environment during the receding tide. This problem constitutes an elastic analogue to the Landau-Levich problem, where the thickness of the deposited fluid layer depends on the elasticity of the overlying sheet. I contrast the slow dynamics of the outgoing tide with the relatively fast dynamics of water entering the subglacial cavity during the incoming tide in chapter 3. This results in a non-linear filter between the ocean tides and the water pressure below the upstream ice sheet. In chapter 4, I develop a model for the deformation of subglacial sediment subject to these ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Warburton, Katarzyna |
author_facet |
Warburton, Katarzyna |
author_sort |
Warburton, Katarzyna |
title |
The Response of Antarctic Ice Streams to Tidal Forcing |
title_short |
The Response of Antarctic Ice Streams to Tidal Forcing |
title_full |
The Response of Antarctic Ice Streams to Tidal Forcing |
title_fullStr |
The Response of Antarctic Ice Streams to Tidal Forcing |
title_full_unstemmed |
The Response of Antarctic Ice Streams to Tidal Forcing |
title_sort |
response of antarctic ice streams to tidal forcing |
publisher |
University of Cambridge |
publishDate |
2022 |
url |
https://www.repository.cam.ac.uk/handle/1810/342322 https://doi.org/10.17863/CAM.89743 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/342322 doi:10.17863/CAM.89743 |
op_rights |
Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.17863/CAM.89743 |
_version_ |
1788690881915650048 |