The Flow Dynamics and Buttressing of Ice Shelves
In this thesis, I explore the flow dynamics associated with ice shelves confined within channels and the buttressing they provide to grounded ice. Ice shelves are the floating extensions of ice sheets and act as the interface between the ice sheet and the ocean. They form when ice flows out from the...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/276046 2023-07-30T03:59:16+02:00 The Flow Dynamics and Buttressing of Ice Shelves Wearing, Martin 2018-05-21T19:21:04Z application/pdf https://doi.org/10.17863/CAM.23327 https://www.repository.cam.ac.uk/handle/1810/276046 en eng Downing DAMTP University of Cambridge doi:10.17863/CAM.23327 https://www.repository.cam.ac.uk/handle/1810/276046 All rights reserved https://www.rioxx.net/licenses/all-rights-reserved/ Ice shelves ice sheet antarctica glaciology fluid dynamics ice shelf Thesis Doctoral Doctor of Philosophy (PhD) PhD in Applied Mathematics with British Antarctic Survey 2018 ftunivcam https://doi.org/10.17863/CAM.23327 2023-07-10T22:06:24Z In this thesis, I explore the flow dynamics associated with ice shelves confined within channels and the buttressing they provide to grounded ice. Ice shelves are the floating extensions of ice sheets and act as the interface between the ice sheet and the ocean. They form when ice flows out from the interior of the ice sheet towards the coast and begins to float as the ice thins. Ice shelves are often found within a channel or pinned in place by stationary bedrock outcrops. The interest in their dynamics is motivated by the buttressing effect they provide to the grounded ice, which strongly controls the rate of ice discharge and thereby the contribution to sea-level rise. I use a combination of mathematical modeling, fluid-mechanical laboratory experiments and geophysical data analysis to develop an improved understanding of ice-shelf flow dynamics. Initially, geophysical data in the form of Antarctic ice-surface velocity data is analysed, producing maps of strain rate, shear rate and strain orientation for Antarctic ice shelves. This allows the geophysical setting and flow processes to be explored, particularly by identifying areas where resistance to ice flow is generated and regions of the shelf that make no contribution to buttressing. Using the geophysical data, I find good agreement between a theoretical scaling relationship for ice flow at the ice-shelf calving front and data from Antarctic ice shelves. I proceed to develop an idealized mathematical model of an ice shelf confined to flow in a channel. By assuming shear-dominated dynamics within the shelf, analytical solutions are obtained for steady-state ice-shelf thickness profiles in parallel and diverging channels. This model is developed further to include both shear and extensional stresses, from which numerical solutions for steady-state shelves are calculated. The results from these two models are then compared. It is found that shear stresses dominate the dynamics throughout the majority of the shelf, with adjustment regions at the upstream and ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ice Shelves Apollo - University of Cambridge Repository Antarctic |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Ice shelves ice sheet antarctica glaciology fluid dynamics ice shelf |
spellingShingle |
Ice shelves ice sheet antarctica glaciology fluid dynamics ice shelf Wearing, Martin The Flow Dynamics and Buttressing of Ice Shelves |
topic_facet |
Ice shelves ice sheet antarctica glaciology fluid dynamics ice shelf |
description |
In this thesis, I explore the flow dynamics associated with ice shelves confined within channels and the buttressing they provide to grounded ice. Ice shelves are the floating extensions of ice sheets and act as the interface between the ice sheet and the ocean. They form when ice flows out from the interior of the ice sheet towards the coast and begins to float as the ice thins. Ice shelves are often found within a channel or pinned in place by stationary bedrock outcrops. The interest in their dynamics is motivated by the buttressing effect they provide to the grounded ice, which strongly controls the rate of ice discharge and thereby the contribution to sea-level rise. I use a combination of mathematical modeling, fluid-mechanical laboratory experiments and geophysical data analysis to develop an improved understanding of ice-shelf flow dynamics. Initially, geophysical data in the form of Antarctic ice-surface velocity data is analysed, producing maps of strain rate, shear rate and strain orientation for Antarctic ice shelves. This allows the geophysical setting and flow processes to be explored, particularly by identifying areas where resistance to ice flow is generated and regions of the shelf that make no contribution to buttressing. Using the geophysical data, I find good agreement between a theoretical scaling relationship for ice flow at the ice-shelf calving front and data from Antarctic ice shelves. I proceed to develop an idealized mathematical model of an ice shelf confined to flow in a channel. By assuming shear-dominated dynamics within the shelf, analytical solutions are obtained for steady-state ice-shelf thickness profiles in parallel and diverging channels. This model is developed further to include both shear and extensional stresses, from which numerical solutions for steady-state shelves are calculated. The results from these two models are then compared. It is found that shear stresses dominate the dynamics throughout the majority of the shelf, with adjustment regions at the upstream and ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Wearing, Martin |
author_facet |
Wearing, Martin |
author_sort |
Wearing, Martin |
title |
The Flow Dynamics and Buttressing of Ice Shelves |
title_short |
The Flow Dynamics and Buttressing of Ice Shelves |
title_full |
The Flow Dynamics and Buttressing of Ice Shelves |
title_fullStr |
The Flow Dynamics and Buttressing of Ice Shelves |
title_full_unstemmed |
The Flow Dynamics and Buttressing of Ice Shelves |
title_sort |
flow dynamics and buttressing of ice shelves |
publisher |
Downing |
publishDate |
2018 |
url |
https://doi.org/10.17863/CAM.23327 https://www.repository.cam.ac.uk/handle/1810/276046 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ice Shelves |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ice Shelves |
op_relation |
doi:10.17863/CAM.23327 https://www.repository.cam.ac.uk/handle/1810/276046 |
op_rights |
All rights reserved https://www.rioxx.net/licenses/all-rights-reserved/ |
op_doi |
https://doi.org/10.17863/CAM.23327 |
_version_ |
1772810011834056704 |