A multi-year assessment of the Synthetic Aperture Radar (SAR) signature of supraglacial lake evolution on the George VI ice shelf, Antarctic Peninsula.
Supraglacial lakes (SGLs) that form annually on the ice shelves fringing Antarctica exert a significant influence on the stability and mass balance of the entire ice sheet, yet their continent-wide extent and evolution is poorly constrained. This study aims to overcome the limitations of optical sat...
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2020
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Online Access: | https://hdl.handle.net/1842/37630 https://doi.org/10.7488/era/911 |
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ftunivedinburgh:oai:era.ed.ac.uk:1842/37630 2023-07-30T03:57:29+02:00 A multi-year assessment of the Synthetic Aperture Radar (SAR) signature of supraglacial lake evolution on the George VI ice shelf, Antarctic Peninsula. Freer, Bryony Gourmelen, Noel 2020-08-31 application/pdf https://hdl.handle.net/1842/37630 https://doi.org/10.7488/era/911 en eng The University of Edinburgh https://hdl.handle.net/1842/37630 http://dx.doi.org/10.7488/era/911 SAR Supraglacial Lakes George VI Thesis or Dissertation Masters MSc Master of Science 2020 ftunivedinburgh https://doi.org/10.7488/era/911 2023-07-09T20:31:09Z Supraglacial lakes (SGLs) that form annually on the ice shelves fringing Antarctica exert a significant influence on the stability and mass balance of the entire ice sheet, yet their continent-wide extent and evolution is poorly constrained. This study aims to overcome the limitations of optical satellite imagery by utilising the all-weather, day-and-night capabilities of Synthetic Aperture Radar (SAR) to examine the evolution of SGLs on the George VI ice shelf, Antarctic Peninsula. Sentinel-1 SAR data are analysed across four melt seasons on George VI (2016-2020) in an effort to understand the backscatter signature of SGLs at different stages of development. A distinct cyclical pattern is identified: a sharp drop in backscatter (~10dB) at the beginning of austral summer indicates melt onset, followed by fluctuations reflecting meteorologically-driven melt and re-freeze events and a return to pre-melt values into winter. The C-band SAR proves effective at discriminating between open water and ice, but the interim melt and re-freeze stages present more complex signatures that vary across the ice shelf, limiting the ability to isolate the SGL backscatter signature statistically. Alongside an assessment of concurrent meteorological data and optical imagery, the findings have informed the production of a novel detailed schematic of the C-band SAR backscatter signature of SGLs. Finally, we present promising results from the first attempt at a threshold-based classification of Antarctic SGLs directly from SAR imagery; an exciting preliminary step in the effort to develop automated SAR-based SGL detection techniques across Antarctica. Master Thesis Antarc* Antarctic Antarctic Peninsula Antarctica George VI Ice Shelf Ice Sheet Ice Shelf Ice Shelves Edinburgh Research Archive (ERA - University of Edinburgh) Antarctic Antarctic Peninsula Austral George VI Ice Shelf ENVELOPE(-67.840,-67.840,-71.692,-71.692) |
institution |
Open Polar |
collection |
Edinburgh Research Archive (ERA - University of Edinburgh) |
op_collection_id |
ftunivedinburgh |
language |
English |
topic |
SAR Supraglacial Lakes George VI |
spellingShingle |
SAR Supraglacial Lakes George VI Freer, Bryony A multi-year assessment of the Synthetic Aperture Radar (SAR) signature of supraglacial lake evolution on the George VI ice shelf, Antarctic Peninsula. |
topic_facet |
SAR Supraglacial Lakes George VI |
description |
Supraglacial lakes (SGLs) that form annually on the ice shelves fringing Antarctica exert a significant influence on the stability and mass balance of the entire ice sheet, yet their continent-wide extent and evolution is poorly constrained. This study aims to overcome the limitations of optical satellite imagery by utilising the all-weather, day-and-night capabilities of Synthetic Aperture Radar (SAR) to examine the evolution of SGLs on the George VI ice shelf, Antarctic Peninsula. Sentinel-1 SAR data are analysed across four melt seasons on George VI (2016-2020) in an effort to understand the backscatter signature of SGLs at different stages of development. A distinct cyclical pattern is identified: a sharp drop in backscatter (~10dB) at the beginning of austral summer indicates melt onset, followed by fluctuations reflecting meteorologically-driven melt and re-freeze events and a return to pre-melt values into winter. The C-band SAR proves effective at discriminating between open water and ice, but the interim melt and re-freeze stages present more complex signatures that vary across the ice shelf, limiting the ability to isolate the SGL backscatter signature statistically. Alongside an assessment of concurrent meteorological data and optical imagery, the findings have informed the production of a novel detailed schematic of the C-band SAR backscatter signature of SGLs. Finally, we present promising results from the first attempt at a threshold-based classification of Antarctic SGLs directly from SAR imagery; an exciting preliminary step in the effort to develop automated SAR-based SGL detection techniques across Antarctica. |
author2 |
Gourmelen, Noel |
format |
Master Thesis |
author |
Freer, Bryony |
author_facet |
Freer, Bryony |
author_sort |
Freer, Bryony |
title |
A multi-year assessment of the Synthetic Aperture Radar (SAR) signature of supraglacial lake evolution on the George VI ice shelf, Antarctic Peninsula. |
title_short |
A multi-year assessment of the Synthetic Aperture Radar (SAR) signature of supraglacial lake evolution on the George VI ice shelf, Antarctic Peninsula. |
title_full |
A multi-year assessment of the Synthetic Aperture Radar (SAR) signature of supraglacial lake evolution on the George VI ice shelf, Antarctic Peninsula. |
title_fullStr |
A multi-year assessment of the Synthetic Aperture Radar (SAR) signature of supraglacial lake evolution on the George VI ice shelf, Antarctic Peninsula. |
title_full_unstemmed |
A multi-year assessment of the Synthetic Aperture Radar (SAR) signature of supraglacial lake evolution on the George VI ice shelf, Antarctic Peninsula. |
title_sort |
multi-year assessment of the synthetic aperture radar (sar) signature of supraglacial lake evolution on the george vi ice shelf, antarctic peninsula. |
publisher |
The University of Edinburgh |
publishDate |
2020 |
url |
https://hdl.handle.net/1842/37630 https://doi.org/10.7488/era/911 |
long_lat |
ENVELOPE(-67.840,-67.840,-71.692,-71.692) |
geographic |
Antarctic Antarctic Peninsula Austral George VI Ice Shelf |
geographic_facet |
Antarctic Antarctic Peninsula Austral George VI Ice Shelf |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica George VI Ice Shelf Ice Sheet Ice Shelf Ice Shelves |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica George VI Ice Shelf Ice Sheet Ice Shelf Ice Shelves |
op_relation |
https://hdl.handle.net/1842/37630 http://dx.doi.org/10.7488/era/911 |
op_doi |
https://doi.org/10.7488/era/911 |
_version_ |
1772817653773107200 |