Improving arctic sea ice thickness estimates from satellite altimetry
Satellite observations have shown that the arctic sea ice extent has strongly decreased during the last 40 years, with a clear increase of the shrinking since the 90's. While the mechanisms responsible for this accelerated shrinking are relatively well known, sea ice models do not clearly repro...
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Other Authors: | , , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
2017
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Online Access: | https://theses.hal.science/tel-02924618 https://theses.hal.science/tel-02924618/document https://theses.hal.science/tel-02924618/file/2017TOU30277b.pdf |
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ftinsu:oai:HAL:tel-02924618v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
French |
topic |
Low resolution mode Synthetic aperture radar Sea ice Freeboard Ice thickness Arctique Banquise Neige Franc-bord Epaisseur de glace [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
Low resolution mode Synthetic aperture radar Sea ice Freeboard Ice thickness Arctique Banquise Neige Franc-bord Epaisseur de glace [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Guerreiro, Kévin Improving arctic sea ice thickness estimates from satellite altimetry |
topic_facet |
Low resolution mode Synthetic aperture radar Sea ice Freeboard Ice thickness Arctique Banquise Neige Franc-bord Epaisseur de glace [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
Satellite observations have shown that the arctic sea ice extent has strongly decreased during the last 40 years, with a clear increase of the shrinking since the 90's. While the mechanisms responsible for this accelerated shrinking are relatively well known, sea ice models do not clearly reproduce the observed extent variations. This inaccurate representation is generally attributed to a misunderstanding of the arctic system climate feedbacks. Among these feedbacks, we seek to study one of them in particular: the sea ice thinning. Sea ice thinning is generally associated with an earlier seasonal melt as well as an increase in sea ice export; both tend to accelerate the sea ice retreat. A good representation of sea ice thickness is therefore necessary to improve our understanding of the arctic sea ice extent variations observed during the last decades. Unlike sea ice extent data, there are currently no pan-Arctic sea ice thickness observations covering a large period (> 20 years). However, several studies have demonstrated the potential of satellite altimetry to retrieve sea ice thickness at a basin scale. To measure sea ice thickness from radar altimetry, the "freeboard" technique is generally employed. This methodology consists of estimating the thickness of the emerged sea ice (freeboard) from radar altimetry and then converting this measurement to sea ice thickness, using an equation for the hydrostatic equilibrium that exists between the snow covered sea ice and the ocean. The freeboard methodology has been applied to diverse altimetric missions (ERS-2, Envisat and CryoSat-2) since 1995 and should allow the retrieval of more than 20 years of pan-Arctic ice thickness. However, the previous estimates of sea ice thickness are data shorter than 6 years in duration. This absence of a long ice thickness time series is mostly due to the difficulty in providing continuity between the different altimetric missions (conventional altimetry/SAR altimetry) as well as to the uncertainties related to the ... |
author2 |
Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université de Toulouse (UT)-Université de Toulouse (UT)-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)-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-Centre National de la Recherche Scientifique (CNRS) Université Paul Sabatier - Toulouse III Alexei Kouraev Elena Zakharova |
format |
Doctoral or Postdoctoral Thesis |
author |
Guerreiro, Kévin |
author_facet |
Guerreiro, Kévin |
author_sort |
Guerreiro, Kévin |
title |
Improving arctic sea ice thickness estimates from satellite altimetry |
title_short |
Improving arctic sea ice thickness estimates from satellite altimetry |
title_full |
Improving arctic sea ice thickness estimates from satellite altimetry |
title_fullStr |
Improving arctic sea ice thickness estimates from satellite altimetry |
title_full_unstemmed |
Improving arctic sea ice thickness estimates from satellite altimetry |
title_sort |
improving arctic sea ice thickness estimates from satellite altimetry |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://theses.hal.science/tel-02924618 https://theses.hal.science/tel-02924618/document https://theses.hal.science/tel-02924618/file/2017TOU30277b.pdf |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Arctique* banquise Sea ice |
genre_facet |
Arctic Arctique* banquise Sea ice |
op_source |
https://theses.hal.science/tel-02924618 Océan, Atmosphère. Université Paul Sabatier - Toulouse III, 2017. Français. ⟨NNT : 2017TOU30277⟩ |
op_relation |
NNT: 2017TOU30277 tel-02924618 https://theses.hal.science/tel-02924618 https://theses.hal.science/tel-02924618/document https://theses.hal.science/tel-02924618/file/2017TOU30277b.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1785569758165336064 |
spelling |
ftinsu:oai:HAL:tel-02924618v1 2023-12-17T10:24:45+01:00 Improving arctic sea ice thickness estimates from satellite altimetry Amélioration des estimations d'épaisseur de glace de mer arctique par altimétrie spatiale Guerreiro, Kévin Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université de Toulouse (UT)-Université de Toulouse (UT)-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)-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-Centre National de la Recherche Scientifique (CNRS) Université Paul Sabatier - Toulouse III Alexei Kouraev Elena Zakharova 2017-09-22 https://theses.hal.science/tel-02924618 https://theses.hal.science/tel-02924618/document https://theses.hal.science/tel-02924618/file/2017TOU30277b.pdf fr fre HAL CCSD NNT: 2017TOU30277 tel-02924618 https://theses.hal.science/tel-02924618 https://theses.hal.science/tel-02924618/document https://theses.hal.science/tel-02924618/file/2017TOU30277b.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-02924618 Océan, Atmosphère. Université Paul Sabatier - Toulouse III, 2017. Français. ⟨NNT : 2017TOU30277⟩ Low resolution mode Synthetic aperture radar Sea ice Freeboard Ice thickness Arctique Banquise Neige Franc-bord Epaisseur de glace [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/doctoralThesis Theses 2017 ftinsu 2023-11-22T17:40:12Z Satellite observations have shown that the arctic sea ice extent has strongly decreased during the last 40 years, with a clear increase of the shrinking since the 90's. While the mechanisms responsible for this accelerated shrinking are relatively well known, sea ice models do not clearly reproduce the observed extent variations. This inaccurate representation is generally attributed to a misunderstanding of the arctic system climate feedbacks. Among these feedbacks, we seek to study one of them in particular: the sea ice thinning. Sea ice thinning is generally associated with an earlier seasonal melt as well as an increase in sea ice export; both tend to accelerate the sea ice retreat. A good representation of sea ice thickness is therefore necessary to improve our understanding of the arctic sea ice extent variations observed during the last decades. Unlike sea ice extent data, there are currently no pan-Arctic sea ice thickness observations covering a large period (> 20 years). However, several studies have demonstrated the potential of satellite altimetry to retrieve sea ice thickness at a basin scale. To measure sea ice thickness from radar altimetry, the "freeboard" technique is generally employed. This methodology consists of estimating the thickness of the emerged sea ice (freeboard) from radar altimetry and then converting this measurement to sea ice thickness, using an equation for the hydrostatic equilibrium that exists between the snow covered sea ice and the ocean. The freeboard methodology has been applied to diverse altimetric missions (ERS-2, Envisat and CryoSat-2) since 1995 and should allow the retrieval of more than 20 years of pan-Arctic ice thickness. However, the previous estimates of sea ice thickness are data shorter than 6 years in duration. This absence of a long ice thickness time series is mostly due to the difficulty in providing continuity between the different altimetric missions (conventional altimetry/SAR altimetry) as well as to the uncertainties related to the ... Doctoral or Postdoctoral Thesis Arctic Arctique* banquise Sea ice Institut national des sciences de l'Univers: HAL-INSU Arctic |