Characterizing the subglacial hydrology of Thwaites Glacier, West Antarctica using airborne radar sounding
text Hydrologic, lithologic, and geothermal basal boundary conditions can exert strong, even dominating, control on the evolution, stability, and sea level contribution of ice sheets and glaciers. However, the scales at which the physical processes and observable signatures of this control occur are...
Main Author: | |
---|---|
Other Authors: | , , , , , |
Format: | Thesis |
Language: | English |
Published: |
2014
|
Subjects: | |
Online Access: | http://hdl.handle.net/2152/32606 https://doi.org/10.15781/T2T63Q |
id |
ftunivtexas:oai:repositories.lib.utexas.edu:2152/32606 |
---|---|
record_format |
openpolar |
spelling |
ftunivtexas:oai:repositories.lib.utexas.edu:2152/32606 2023-05-15T14:03:05+02:00 Characterizing the subglacial hydrology of Thwaites Glacier, West Antarctica using airborne radar sounding Schroeder, Dustin Matthew Blankenship, Donald D. Raney, R. Keith Anderson, John B Ghattas, Omar Hesse, Marc A Mohrig, David 2014-05 application/pdf http://hdl.handle.net/2152/32606 https://doi.org/10.15781/T2T63Q en eng doi:10.15781/T2T63Q http://hdl.handle.net/2152/32606 Thwaites Glacier Antarctica Airborne radar sounding West Antarctic Ice Sheet Subglacial Hydrology Thesis 2014 ftunivtexas https://doi.org/10.15781/T2T63Q 2020-12-23T22:20:49Z text Hydrologic, lithologic, and geothermal basal boundary conditions can exert strong, even dominating, control on the evolution, stability, and sea level contribution of ice sheets and glaciers. However, the scales at which the physical processes and observable signatures of this control occur are typically smaller than the spatial resolutions currently achievable using ice penetrating radar. Further, the strength of radar bed echo returns is affected by the material and geometric properties of the bed as well as englacial attenuation from unknown ice temperature and chemistry, making assessment of basal conditions from echo strengths difficult. To address these challenges in interpreting basal properties at glaciologically relevant scales, a new algorithmic approach is applied to measuring the radar scattering function of the bed in terms of the relative contribution of angularly narrow specular energy and isotropically scattered diffuse energy. This relative specularity content is insensitive to englacial attenuation and can be used to constrain the geometry of the bed down to the centimeter scale. This approach is applied to an airborne radar sounding survey of Thwaites Glacier, West Antarctica using the information in the along-track scattering function to assess the extent and geometry of water across the catchment and detect the transition of that water from distributed canals to concentrated channels. This information is also used to constrain the morphology of subglacial bedforms and infer that the distribution of deformable sediments and exposed bedrock is similar to deglaciated paleo ice streams that experienced meltwater intensive retreats. Finally, models of radar echo strength and subglacial water routing are compared to estimate a catchment-wide distribution of geothermal flux consistent with rift-associated magma migration and volcanism. These observations of basal conditions provide new context for the past, current, and future evolution of Thwaites Glacier, the West Antarctic Ice Sheet, and their contribution to global sea level. Geological Sciences Thesis Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica The University of Texas at Austin: Texas ScholarWorks Antarctic West Antarctica West Antarctic Ice Sheet Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
institution |
Open Polar |
collection |
The University of Texas at Austin: Texas ScholarWorks |
op_collection_id |
ftunivtexas |
language |
English |
topic |
Thwaites Glacier Antarctica Airborne radar sounding West Antarctic Ice Sheet Subglacial Hydrology |
spellingShingle |
Thwaites Glacier Antarctica Airborne radar sounding West Antarctic Ice Sheet Subglacial Hydrology Schroeder, Dustin Matthew Characterizing the subglacial hydrology of Thwaites Glacier, West Antarctica using airborne radar sounding |
topic_facet |
Thwaites Glacier Antarctica Airborne radar sounding West Antarctic Ice Sheet Subglacial Hydrology |
description |
text Hydrologic, lithologic, and geothermal basal boundary conditions can exert strong, even dominating, control on the evolution, stability, and sea level contribution of ice sheets and glaciers. However, the scales at which the physical processes and observable signatures of this control occur are typically smaller than the spatial resolutions currently achievable using ice penetrating radar. Further, the strength of radar bed echo returns is affected by the material and geometric properties of the bed as well as englacial attenuation from unknown ice temperature and chemistry, making assessment of basal conditions from echo strengths difficult. To address these challenges in interpreting basal properties at glaciologically relevant scales, a new algorithmic approach is applied to measuring the radar scattering function of the bed in terms of the relative contribution of angularly narrow specular energy and isotropically scattered diffuse energy. This relative specularity content is insensitive to englacial attenuation and can be used to constrain the geometry of the bed down to the centimeter scale. This approach is applied to an airborne radar sounding survey of Thwaites Glacier, West Antarctica using the information in the along-track scattering function to assess the extent and geometry of water across the catchment and detect the transition of that water from distributed canals to concentrated channels. This information is also used to constrain the morphology of subglacial bedforms and infer that the distribution of deformable sediments and exposed bedrock is similar to deglaciated paleo ice streams that experienced meltwater intensive retreats. Finally, models of radar echo strength and subglacial water routing are compared to estimate a catchment-wide distribution of geothermal flux consistent with rift-associated magma migration and volcanism. These observations of basal conditions provide new context for the past, current, and future evolution of Thwaites Glacier, the West Antarctic Ice Sheet, and their contribution to global sea level. Geological Sciences |
author2 |
Blankenship, Donald D. Raney, R. Keith Anderson, John B Ghattas, Omar Hesse, Marc A Mohrig, David |
format |
Thesis |
author |
Schroeder, Dustin Matthew |
author_facet |
Schroeder, Dustin Matthew |
author_sort |
Schroeder, Dustin Matthew |
title |
Characterizing the subglacial hydrology of Thwaites Glacier, West Antarctica using airborne radar sounding |
title_short |
Characterizing the subglacial hydrology of Thwaites Glacier, West Antarctica using airborne radar sounding |
title_full |
Characterizing the subglacial hydrology of Thwaites Glacier, West Antarctica using airborne radar sounding |
title_fullStr |
Characterizing the subglacial hydrology of Thwaites Glacier, West Antarctica using airborne radar sounding |
title_full_unstemmed |
Characterizing the subglacial hydrology of Thwaites Glacier, West Antarctica using airborne radar sounding |
title_sort |
characterizing the subglacial hydrology of thwaites glacier, west antarctica using airborne radar sounding |
publishDate |
2014 |
url |
http://hdl.handle.net/2152/32606 https://doi.org/10.15781/T2T63Q |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Antarctic West Antarctica West Antarctic Ice Sheet Thwaites Glacier |
geographic_facet |
Antarctic West Antarctica West Antarctic Ice Sheet Thwaites Glacier |
genre |
Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica |
op_relation |
doi:10.15781/T2T63Q http://hdl.handle.net/2152/32606 |
op_doi |
https://doi.org/10.15781/T2T63Q |
_version_ |
1766273618118967296 |