Development of SARAL/AltiKa altimetric data over the Antarctic ice sheet
Antarctica still remains a fascinating place to be explored. With ice corings, the past Earth climate can be retraced. Studying its surface, its climate variability and its dynamic are better known : ice velocity, iceberg calvings. . . Through the height variations monitoring, ice gains and losses a...
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Other Authors: | , , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
2016
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Online Access: | https://theses.hal.science/tel-01398061 https://theses.hal.science/tel-01398061v2/document https://theses.hal.science/tel-01398061v2/file/2016TOU30091b.pdf |
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ftunivnantes:oai:HAL:tel-01398061v2 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
French |
topic |
Remote Sensing Data processing Signal processing Altimetry Antarctica SARAL ENVISAT ICESat Télédétection Traitement de données Traitement du signal Altimétrie Antarctique [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
spellingShingle |
Remote Sensing Data processing Signal processing Altimetry Antarctica SARAL ENVISAT ICESat Télédétection Traitement de données Traitement du signal Altimétrie Antarctique [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology Michel, Aurélie Development of SARAL/AltiKa altimetric data over the Antarctic ice sheet |
topic_facet |
Remote Sensing Data processing Signal processing Altimetry Antarctica SARAL ENVISAT ICESat Télédétection Traitement de données Traitement du signal Altimétrie Antarctique [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
description |
Antarctica still remains a fascinating place to be explored. With ice corings, the past Earth climate can be retraced. Studying its surface, its climate variability and its dynamic are better known : ice velocity, iceberg calvings. . . Through the height variations monitoring, ice gains and losses are estimated, leading to the contribution to the sea-level rise, from which is deduced the impact over coastal areas or the oceans. To explore this continent, we use the sensor called altimeter : a radar or laser wave is sent from the satellite to the surface and the reflected signal is recorded. From this signal we extract relevant parameters and the height. The satellites have observed this area, notably since the altimetric mission ERS-1 launching, until 82æ S in 1991, following the still famous explorations from the beginning of the twentieth century. SARAL, launched in February 2013, innovates because of the major change in the frequency used, the Ka-band (36.75 Ghz) instead of the Ku-band (13.6Ghz) and the S-band (3.2 Ghz) implying a different interaction between the radar wave and the snowpack that needs to be investigated. Using almost three years of observations, we focus on the altimetric signal processing and its validation. The geographic and the technical aspects are introduced and we show the limitations in the altimetric data processing. Using the crossover method (explained in greater detail later), we compare two simultaneous missions, ENVISAT and ICESat in order to better constrain the penetration effect of the radar-wave into the snowpack and correct it. The method that is used will be of great interest to compare SARAL with the future mission ICESat- 2. A new calibration and validation tool has been implemented, allowing a long-term survey of the Antarctic area, providing statistics, diagnostics and temporal series. The slope effect is the major limitation in the precision assessment of the mission. Thanks to a new way of selecting the data and the oceanic tide correction, we quantify with metrics ... |
author2 |
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) Université Paul Sabatier - Toulouse III Frédérique Rémy Annabelle Ollivier |
format |
Doctoral or Postdoctoral Thesis |
author |
Michel, Aurélie |
author_facet |
Michel, Aurélie |
author_sort |
Michel, Aurélie |
title |
Development of SARAL/AltiKa altimetric data over the Antarctic ice sheet |
title_short |
Development of SARAL/AltiKa altimetric data over the Antarctic ice sheet |
title_full |
Development of SARAL/AltiKa altimetric data over the Antarctic ice sheet |
title_fullStr |
Development of SARAL/AltiKa altimetric data over the Antarctic ice sheet |
title_full_unstemmed |
Development of SARAL/AltiKa altimetric data over the Antarctic ice sheet |
title_sort |
development of saral/altika altimetric data over the antarctic ice sheet |
publisher |
HAL CCSD |
publishDate |
2016 |
url |
https://theses.hal.science/tel-01398061 https://theses.hal.science/tel-01398061v2/document https://theses.hal.science/tel-01398061v2/file/2016TOU30091b.pdf |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Antarctica Antarctique* Ice Sheet Iceberg* |
genre_facet |
Antarc* Antarctic Antarctica Antarctique* Ice Sheet Iceberg* |
op_source |
https://theses.hal.science/tel-01398061 Climatologie. Université Paul Sabatier - Toulouse III, 2016. Français. ⟨NNT : 2016TOU30091⟩ |
op_relation |
NNT: 2016TOU30091 tel-01398061 https://theses.hal.science/tel-01398061 https://theses.hal.science/tel-01398061v2/document https://theses.hal.science/tel-01398061v2/file/2016TOU30091b.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766249555613974528 |
spelling |
ftunivnantes:oai:HAL:tel-01398061v2 2023-05-15T13:48:40+02:00 Development of SARAL/AltiKa altimetric data over the Antarctic ice sheet Valorisation des données altimétriques de SARAL/AltiKa pour l'étude de la calotte Antarctique Michel, Aurélie 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) Université Paul Sabatier - Toulouse III Frédérique Rémy Annabelle Ollivier 2016-06-28 https://theses.hal.science/tel-01398061 https://theses.hal.science/tel-01398061v2/document https://theses.hal.science/tel-01398061v2/file/2016TOU30091b.pdf fr fre HAL CCSD NNT: 2016TOU30091 tel-01398061 https://theses.hal.science/tel-01398061 https://theses.hal.science/tel-01398061v2/document https://theses.hal.science/tel-01398061v2/file/2016TOU30091b.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01398061 Climatologie. Université Paul Sabatier - Toulouse III, 2016. Français. ⟨NNT : 2016TOU30091⟩ Remote Sensing Data processing Signal processing Altimetry Antarctica SARAL ENVISAT ICESat Télédétection Traitement de données Traitement du signal Altimétrie Antarctique [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology info:eu-repo/semantics/doctoralThesis Theses 2016 ftunivnantes 2023-03-08T06:52:48Z Antarctica still remains a fascinating place to be explored. With ice corings, the past Earth climate can be retraced. Studying its surface, its climate variability and its dynamic are better known : ice velocity, iceberg calvings. . . Through the height variations monitoring, ice gains and losses are estimated, leading to the contribution to the sea-level rise, from which is deduced the impact over coastal areas or the oceans. To explore this continent, we use the sensor called altimeter : a radar or laser wave is sent from the satellite to the surface and the reflected signal is recorded. From this signal we extract relevant parameters and the height. The satellites have observed this area, notably since the altimetric mission ERS-1 launching, until 82æ S in 1991, following the still famous explorations from the beginning of the twentieth century. SARAL, launched in February 2013, innovates because of the major change in the frequency used, the Ka-band (36.75 Ghz) instead of the Ku-band (13.6Ghz) and the S-band (3.2 Ghz) implying a different interaction between the radar wave and the snowpack that needs to be investigated. Using almost three years of observations, we focus on the altimetric signal processing and its validation. The geographic and the technical aspects are introduced and we show the limitations in the altimetric data processing. Using the crossover method (explained in greater detail later), we compare two simultaneous missions, ENVISAT and ICESat in order to better constrain the penetration effect of the radar-wave into the snowpack and correct it. The method that is used will be of great interest to compare SARAL with the future mission ICESat- 2. A new calibration and validation tool has been implemented, allowing a long-term survey of the Antarctic area, providing statistics, diagnostics and temporal series. The slope effect is the major limitation in the precision assessment of the mission. Thanks to a new way of selecting the data and the oceanic tide correction, we quantify with metrics ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctica Antarctique* Ice Sheet Iceberg* Université de Nantes: HAL-UNIV-NANTES Antarctic The Antarctic |