Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet
Spaceborne radar altimeters are a valuable tool for observing the Antarctic Ice Sheet. The radar wave interaction with the snow provides information on both the surface and the subsurface of the snowpack due to its dependence on the snow properties. However, the penetration of the radar wave within...
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ftcopernicus:oai:publications.copernicus.org:tc62851 2023-05-15T13:55:28+02:00 Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet Adodo, Fifi Ibrahime Remy, Frédérique Picard, Ghislain 2019-01-10 application/pdf https://doi.org/10.5194/tc-12-1767-2018 https://tc.copernicus.org/articles/12/1767/2018/ eng eng doi:10.5194/tc-12-1767-2018 https://tc.copernicus.org/articles/12/1767/2018/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-12-1767-2018 2020-07-20T16:23:18Z Spaceborne radar altimeters are a valuable tool for observing the Antarctic Ice Sheet. The radar wave interaction with the snow provides information on both the surface and the subsurface of the snowpack due to its dependence on the snow properties. However, the penetration of the radar wave within the snowpack also induces a negative bias on the estimated surface elevation. Empirical corrections of this space- and time-varying bias are usually based on the backscattering coefficient variability. We investigate the spatial and seasonal variations of the backscattering coefficient at the S (3.2 GHz ∼ 9.4 cm), Ku (13.6 GHz ∼ 2.3 cm) and Ka (37 GHz ∼ 0.8 cm) bands. We identified that the backscattering coefficient at Ku band reaches a maximum in winter in part of the continent (Region 1) and in the summer in the remaining (Region 2), while the evolution at other frequencies is relatively uniform over the whole continent. To explain this contrasting behavior between frequencies and between regions, we studied the sensitivity of the backscattering coefficient at three frequencies to several parameters (surface snow density, snow temperature and snow grain size) using an electromagnetic model. The results show that the seasonal cycle of the backscattering coefficient at Ka frequency is dominated by the volume echo and is mainly driven by snow temperature evolution everywhere. In contrast, at S band, the cycle is dominated by the surface echo. At Ku band, the seasonal cycle is dominated by the volume echo in Region 1 and by the surface echo in Region 2. This investigation provides new information on the seasonal dynamics of the Antarctic Ice Sheet surface and provides new clues to build more accurate corrections of the radar altimeter surface elevation signal in the future. Text Antarc* Antarctic Ice Sheet Copernicus Publications: E-Journals Antarctic The Antarctic The Cryosphere 12 5 1767 1778 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
Spaceborne radar altimeters are a valuable tool for observing the Antarctic Ice Sheet. The radar wave interaction with the snow provides information on both the surface and the subsurface of the snowpack due to its dependence on the snow properties. However, the penetration of the radar wave within the snowpack also induces a negative bias on the estimated surface elevation. Empirical corrections of this space- and time-varying bias are usually based on the backscattering coefficient variability. We investigate the spatial and seasonal variations of the backscattering coefficient at the S (3.2 GHz ∼ 9.4 cm), Ku (13.6 GHz ∼ 2.3 cm) and Ka (37 GHz ∼ 0.8 cm) bands. We identified that the backscattering coefficient at Ku band reaches a maximum in winter in part of the continent (Region 1) and in the summer in the remaining (Region 2), while the evolution at other frequencies is relatively uniform over the whole continent. To explain this contrasting behavior between frequencies and between regions, we studied the sensitivity of the backscattering coefficient at three frequencies to several parameters (surface snow density, snow temperature and snow grain size) using an electromagnetic model. The results show that the seasonal cycle of the backscattering coefficient at Ka frequency is dominated by the volume echo and is mainly driven by snow temperature evolution everywhere. In contrast, at S band, the cycle is dominated by the surface echo. At Ku band, the seasonal cycle is dominated by the volume echo in Region 1 and by the surface echo in Region 2. This investigation provides new information on the seasonal dynamics of the Antarctic Ice Sheet surface and provides new clues to build more accurate corrections of the radar altimeter surface elevation signal in the future. |
format |
Text |
author |
Adodo, Fifi Ibrahime Remy, Frédérique Picard, Ghislain |
spellingShingle |
Adodo, Fifi Ibrahime Remy, Frédérique Picard, Ghislain Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet |
author_facet |
Adodo, Fifi Ibrahime Remy, Frédérique Picard, Ghislain |
author_sort |
Adodo, Fifi Ibrahime |
title |
Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet |
title_short |
Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet |
title_full |
Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet |
title_fullStr |
Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet |
title_full_unstemmed |
Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet |
title_sort |
seasonal variations of the backscattering coefficient measured by radar altimeters over the antarctic ice sheet |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-12-1767-2018 https://tc.copernicus.org/articles/12/1767/2018/ |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-12-1767-2018 https://tc.copernicus.org/articles/12/1767/2018/ |
op_doi |
https://doi.org/10.5194/tc-12-1767-2018 |
container_title |
The Cryosphere |
container_volume |
12 |
container_issue |
5 |
container_start_page |
1767 |
op_container_end_page |
1778 |
_version_ |
1766262132257587200 |