Evaluation of SAR altimetry over the antarctic ice sheet from CryoSat-2 acquisitions
International audience Since the 1990s and the launch of ERS-1, Earth's polar regions have been near continuously monitored by satellite altimetry, improving substantially our knowledge of the ice sheet topography and its evolution. CryoSat-2 is the first satellite carrying on-board a new gener...
Published in: | Advances in Space Research |
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Online Access: | https://hal-insu.archives-ouvertes.fr/insu-03670737 https://doi.org/10.1016/j.asr.2018.06.043 |
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ftunivnantes:oai:HAL:insu-03670737v1 2023-05-15T13:04:20+02:00 Evaluation of SAR altimetry over the antarctic ice sheet from CryoSat-2 acquisitions Aublanc, J. Moreau, T. Thibaut, P. Boy, F. Rémy, F. Picot, N. Centre National d'Études Spatiales Toulouse (CNES) Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS) 2018 https://hal-insu.archives-ouvertes.fr/insu-03670737 https://doi.org/10.1016/j.asr.2018.06.043 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.1016/j.asr.2018.06.043 insu-03670737 https://hal-insu.archives-ouvertes.fr/insu-03670737 BIBCODE: 2018AdSpR.62.1307A doi:10.1016/j.asr.2018.06.043 Advances in Space Research https://hal-insu.archives-ouvertes.fr/insu-03670737 Advances in Space Research, 2018, 62, pp.1307-1323. ⟨10.1016/j.asr.2018.06.043⟩ CryoSat-2 Antarctic ice sheet SAR altimetry Radar altimetry [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2018 ftunivnantes https://doi.org/10.1016/j.asr.2018.06.043 2023-02-22T01:57:58Z International audience Since the 1990s and the launch of ERS-1, Earth's polar regions have been near continuously monitored by satellite altimetry, improving substantially our knowledge of the ice sheet topography and its evolution. CryoSat-2 is the first satellite carrying on-board a new generation of radar altimeter able to operate in a Synthetic Aperture Radar (SAR) mode. In comparison with the Low Resolution Mode (LRM) used in conventional radar altimetry, SAR mode allows to reduce the along-track footprint from several kilometers to 300 m. In this paper we assess the SAR mode performance over the Antarctic ice sheet using sporadic CryoSat-2 acquisitions carried out in winter 2014 on dedicated zones (Lake Vostok and Adelie land). Level-1 data from two different algorithms are exploited: the CNES Cryosat-2 Processing Prototype (CPP) and the ESA Instrument Processing Facility (IPF). Firstly, results show that the estimated surface elevation from the SAR mode acquisitions over the flat surface of Lake Vostok is within the same order of magnitude as available DEMs. Mean bias is in the order of several centimeters, without any corrections accounting for the snowpack volume scattering. Secondly, the undertaken analyzes evidence that SAR altimetry has either no, or only small, sensitivity to the along-track slope-induced effect, while the across-track slope-induced effect is similar as LRM. Thirdly, SAR altimetry mode appears to be more performant than Pseudo-LRM over the steep slopes of the Antarctica margins. The precision of the estimated surface elevation is improved by 30%, and the processed waveforms are less noisy. Overall, this work demonstrates the improved measuring capability offered by SAR mode altimetry over the ice sheet surface compared to conventional altimetry. Article in Journal/Newspaper Adelie Land Antarc* Antarctic Antarctica Ice Sheet Université de Nantes: HAL-UNIV-NANTES Antarctic Lake Vostok ENVELOPE(106.000,106.000,-77.500,-77.500) The Antarctic Advances in Space Research 62 6 1307 1323 |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
CryoSat-2 Antarctic ice sheet SAR altimetry Radar altimetry [SDU]Sciences of the Universe [physics] |
spellingShingle |
CryoSat-2 Antarctic ice sheet SAR altimetry Radar altimetry [SDU]Sciences of the Universe [physics] Aublanc, J. Moreau, T. Thibaut, P. Boy, F. Rémy, F. Picot, N. Evaluation of SAR altimetry over the antarctic ice sheet from CryoSat-2 acquisitions |
topic_facet |
CryoSat-2 Antarctic ice sheet SAR altimetry Radar altimetry [SDU]Sciences of the Universe [physics] |
description |
International audience Since the 1990s and the launch of ERS-1, Earth's polar regions have been near continuously monitored by satellite altimetry, improving substantially our knowledge of the ice sheet topography and its evolution. CryoSat-2 is the first satellite carrying on-board a new generation of radar altimeter able to operate in a Synthetic Aperture Radar (SAR) mode. In comparison with the Low Resolution Mode (LRM) used in conventional radar altimetry, SAR mode allows to reduce the along-track footprint from several kilometers to 300 m. In this paper we assess the SAR mode performance over the Antarctic ice sheet using sporadic CryoSat-2 acquisitions carried out in winter 2014 on dedicated zones (Lake Vostok and Adelie land). Level-1 data from two different algorithms are exploited: the CNES Cryosat-2 Processing Prototype (CPP) and the ESA Instrument Processing Facility (IPF). Firstly, results show that the estimated surface elevation from the SAR mode acquisitions over the flat surface of Lake Vostok is within the same order of magnitude as available DEMs. Mean bias is in the order of several centimeters, without any corrections accounting for the snowpack volume scattering. Secondly, the undertaken analyzes evidence that SAR altimetry has either no, or only small, sensitivity to the along-track slope-induced effect, while the across-track slope-induced effect is similar as LRM. Thirdly, SAR altimetry mode appears to be more performant than Pseudo-LRM over the steep slopes of the Antarctica margins. The precision of the estimated surface elevation is improved by 30%, and the processed waveforms are less noisy. Overall, this work demonstrates the improved measuring capability offered by SAR mode altimetry over the ice sheet surface compared to conventional altimetry. |
author2 |
Centre National d'Études Spatiales Toulouse (CNES) Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Aublanc, J. Moreau, T. Thibaut, P. Boy, F. Rémy, F. Picot, N. |
author_facet |
Aublanc, J. Moreau, T. Thibaut, P. Boy, F. Rémy, F. Picot, N. |
author_sort |
Aublanc, J. |
title |
Evaluation of SAR altimetry over the antarctic ice sheet from CryoSat-2 acquisitions |
title_short |
Evaluation of SAR altimetry over the antarctic ice sheet from CryoSat-2 acquisitions |
title_full |
Evaluation of SAR altimetry over the antarctic ice sheet from CryoSat-2 acquisitions |
title_fullStr |
Evaluation of SAR altimetry over the antarctic ice sheet from CryoSat-2 acquisitions |
title_full_unstemmed |
Evaluation of SAR altimetry over the antarctic ice sheet from CryoSat-2 acquisitions |
title_sort |
evaluation of sar altimetry over the antarctic ice sheet from cryosat-2 acquisitions |
publisher |
HAL CCSD |
publishDate |
2018 |
url |
https://hal-insu.archives-ouvertes.fr/insu-03670737 https://doi.org/10.1016/j.asr.2018.06.043 |
long_lat |
ENVELOPE(106.000,106.000,-77.500,-77.500) |
geographic |
Antarctic Lake Vostok The Antarctic |
geographic_facet |
Antarctic Lake Vostok The Antarctic |
genre |
Adelie Land Antarc* Antarctic Antarctica Ice Sheet |
genre_facet |
Adelie Land Antarc* Antarctic Antarctica Ice Sheet |
op_source |
Advances in Space Research https://hal-insu.archives-ouvertes.fr/insu-03670737 Advances in Space Research, 2018, 62, pp.1307-1323. ⟨10.1016/j.asr.2018.06.043⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.asr.2018.06.043 insu-03670737 https://hal-insu.archives-ouvertes.fr/insu-03670737 BIBCODE: 2018AdSpR.62.1307A doi:10.1016/j.asr.2018.06.043 |
op_doi |
https://doi.org/10.1016/j.asr.2018.06.043 |
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Advances in Space Research |
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62 |
container_issue |
6 |
container_start_page |
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