Understanding Changes to Glacier and Ice Sheet Geometry: The Roles of Climate and Ice Dynamics
Glacier and ice sheet geometry depend on climatic and ice dynamic processes that are coupled and often highly complex. Thus, partitioning and understanding the drivers of change to glacier and ice sheet geometry requires creative approaches. Radiostratigraphy data document emergent layers in the abl...
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ftproquest:oai:pqdtoai.proquest.com:10934265 2023-05-15T16:21:10+02:00 Understanding Changes to Glacier and Ice Sheet Geometry: The Roles of Climate and Ice Dynamics Florentine, Caitlyn Elizabeth 2018-01-01 00:00:01.0 http://pqdtopen.proquest.com/#viewpdf?dispub=10934265 ENG eng University of Montana http://pqdtopen.proquest.com/#viewpdf?dispub=10934265 Geophysics thesis 2018 ftproquest 2021-03-13T17:33:26Z Glacier and ice sheet geometry depend on climatic and ice dynamic processes that are coupled and often highly complex. Thus, partitioning and understanding the drivers of change to glacier and ice sheet geometry requires creative approaches. Radiostratigraphy data document emergent layers in the ablation zone of western Greenland that emulate theoretical englacial flow paths. Yet true alignment between radar layers and the englacial flow field can be uncertain because these structures have travelled hundreds of km from their original point of deposition, have been shaped by ice deformation for millennia, and have been subjected to complex and three-dimensional ice motion across steep and rugged bedrock terrain. In Chapter 2 I address this problem. Using ice dynamics information from a thermomechanically coupled, higher order ice sheet model, in conjunction with an observationally based test built on principles of mass conservation, I demonstrate that real world effects do not disrupt alignment between targeted ablation zone emergent radar layers and the local, present-day ice flow field. Topographically driven processes such as wind-drifting, avalanching, and shading, can sustain mountain glaciers situated in settings that are otherwise unsuitable for maintaining glacier ice. Local topography can thus disrupt the way regional climate controls glacier retreat, which limits insight into the climate representativeness of some mountain glaciers. In Chapters 3 and 4 I address this issue. Analyzing glaciological, geodetic, and meteorological data, I quantitatively demonstrate that the glacier-climate relationship at a retreating cirque glacier evolved as mass balance processes associated with local topography became more influential from 1950 to 2014. I then assess regional glacier area changes in the Northern Rockies from the Little Ice Age glacial maxima to the modern. I characterize terrain parameters at each glacier and estimate glacier thickness. Using these data and extremely simple models of ice mass loss I assess climatic, topographic, and glaciological drivers. Predictable factors like initial glacier size, aspect, and elevation only partly explain the observed pattern of glacier disappearance. This implies that less predictable and poorly resolved processes like avalanching and wind-drifting drive spatially complex patterns of glacier mass change across this mountain landscape. Thesis glacier Greenland Ice Sheet PQDT Open: Open Access Dissertations and Theses (ProQuest) Greenland Northern Rockies ENVELOPE(-123.446,-123.446,59.074,59.074) |
institution |
Open Polar |
collection |
PQDT Open: Open Access Dissertations and Theses (ProQuest) |
op_collection_id |
ftproquest |
language |
English |
topic |
Geophysics |
spellingShingle |
Geophysics Florentine, Caitlyn Elizabeth Understanding Changes to Glacier and Ice Sheet Geometry: The Roles of Climate and Ice Dynamics |
topic_facet |
Geophysics |
description |
Glacier and ice sheet geometry depend on climatic and ice dynamic processes that are coupled and often highly complex. Thus, partitioning and understanding the drivers of change to glacier and ice sheet geometry requires creative approaches. Radiostratigraphy data document emergent layers in the ablation zone of western Greenland that emulate theoretical englacial flow paths. Yet true alignment between radar layers and the englacial flow field can be uncertain because these structures have travelled hundreds of km from their original point of deposition, have been shaped by ice deformation for millennia, and have been subjected to complex and three-dimensional ice motion across steep and rugged bedrock terrain. In Chapter 2 I address this problem. Using ice dynamics information from a thermomechanically coupled, higher order ice sheet model, in conjunction with an observationally based test built on principles of mass conservation, I demonstrate that real world effects do not disrupt alignment between targeted ablation zone emergent radar layers and the local, present-day ice flow field. Topographically driven processes such as wind-drifting, avalanching, and shading, can sustain mountain glaciers situated in settings that are otherwise unsuitable for maintaining glacier ice. Local topography can thus disrupt the way regional climate controls glacier retreat, which limits insight into the climate representativeness of some mountain glaciers. In Chapters 3 and 4 I address this issue. Analyzing glaciological, geodetic, and meteorological data, I quantitatively demonstrate that the glacier-climate relationship at a retreating cirque glacier evolved as mass balance processes associated with local topography became more influential from 1950 to 2014. I then assess regional glacier area changes in the Northern Rockies from the Little Ice Age glacial maxima to the modern. I characterize terrain parameters at each glacier and estimate glacier thickness. Using these data and extremely simple models of ice mass loss I assess climatic, topographic, and glaciological drivers. Predictable factors like initial glacier size, aspect, and elevation only partly explain the observed pattern of glacier disappearance. This implies that less predictable and poorly resolved processes like avalanching and wind-drifting drive spatially complex patterns of glacier mass change across this mountain landscape. |
format |
Thesis |
author |
Florentine, Caitlyn Elizabeth |
author_facet |
Florentine, Caitlyn Elizabeth |
author_sort |
Florentine, Caitlyn Elizabeth |
title |
Understanding Changes to Glacier and Ice Sheet Geometry: The Roles of Climate and Ice Dynamics |
title_short |
Understanding Changes to Glacier and Ice Sheet Geometry: The Roles of Climate and Ice Dynamics |
title_full |
Understanding Changes to Glacier and Ice Sheet Geometry: The Roles of Climate and Ice Dynamics |
title_fullStr |
Understanding Changes to Glacier and Ice Sheet Geometry: The Roles of Climate and Ice Dynamics |
title_full_unstemmed |
Understanding Changes to Glacier and Ice Sheet Geometry: The Roles of Climate and Ice Dynamics |
title_sort |
understanding changes to glacier and ice sheet geometry: the roles of climate and ice dynamics |
publisher |
University of Montana |
publishDate |
2018 |
url |
http://pqdtopen.proquest.com/#viewpdf?dispub=10934265 |
long_lat |
ENVELOPE(-123.446,-123.446,59.074,59.074) |
geographic |
Greenland Northern Rockies |
geographic_facet |
Greenland Northern Rockies |
genre |
glacier Greenland Ice Sheet |
genre_facet |
glacier Greenland Ice Sheet |
op_relation |
http://pqdtopen.proquest.com/#viewpdf?dispub=10934265 |
_version_ |
1766009183805636608 |