Gas content in polar ice. Present geographic variations, variations over the last climatic cycle in the Vostok region.
Total gas content (V) in polar ice has been used in earlier works as an indicator of ice sheet thickness variations related to climatic change.In this work, a series of experimental tests were performed, which show that the V measurement technique used at LGGE can lead to absolute results within +-1...
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Other Authors: | , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
1990
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Online Access: | https://theses.hal.science/tel-01576069 https://theses.hal.science/tel-01576069/document https://theses.hal.science/tel-01576069/file/Martinerie-PhD-1990.pdf |
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ftunivsavoie:oai:HAL:tel-01576069v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Université Savoie Mont Blanc: HAL |
op_collection_id |
ftunivsavoie |
language |
French |
topic |
glaciology climatology air content ice sheets atmospheric pressure paleo elevations porosity glaciologie climatologie teneur en air calottes glaciaires pression atmosphérique paleo altitudes porosité [PHYS]Physics [physics] |
spellingShingle |
glaciology climatology air content ice sheets atmospheric pressure paleo elevations porosity glaciologie climatologie teneur en air calottes glaciaires pression atmosphérique paleo altitudes porosité [PHYS]Physics [physics] Martinerie, Patricia Gas content in polar ice. Present geographic variations, variations over the last climatic cycle in the Vostok region. |
topic_facet |
glaciology climatology air content ice sheets atmospheric pressure paleo elevations porosity glaciologie climatologie teneur en air calottes glaciaires pression atmosphérique paleo altitudes porosité [PHYS]Physics [physics] |
description |
Total gas content (V) in polar ice has been used in earlier works as an indicator of ice sheet thickness variations related to climatic change.In this work, a series of experimental tests were performed, which show that the V measurement technique used at LGGE can lead to absolute results within +-1,5% accuracy. A calculation is presented to correct V results from the effect of cut bubbles at the surface of the ice samples, which can lead to gas losses ranging between 1 and 10%.The results from sixteen different drilling sites permit a more detailed description of the present V variations with atmospheric pressure and elevation. This work confirms the pore volume at close-off (Vc) - temperature dependence and do not indicate any clear Vc dependence on snow accumulation. Part of the Vc deviations from linear increase with temperature could be due to the wind influence on Vc.Three different analytical methods were used to investigate total gas content along the two deepest Vostok cores, which cover the last climatic cycle. The different results are consistent and show quick and large amplitude V variations. Constraints imposed by ice sheet dynamics strongly suggest that long term V changes cannot be interpreted only in terms of ice sheet thickness variations. The possible impacts of atmospheric pressure changes and non thermal close-off porosity changes are discussed. La teneur en gaz (V) de la glace a été utilisée dans les travaux antérieurs comme indicateur des variations d'épaisseur des calottes polaires en lien avec les changements du climat.Dans ce travail, une série de tests expérimentaux ont montré que la méthode de mesure de V utilisée au LGGE peut fournir des résultats absolus avec une précision de +- 1,5%. Un calcul est présenté pour corriger les résultats de V de l'effet des bulles coupées en surface des échantillons, qui peut induire des pertes de gaz allant de 1 à 10%.Les résultats concernant 16 sites de forage permettent une description plus détaillée des variations géographiques actuelles de V ... |
author2 |
Laboratoire de glaciologie et géophysique de l'environnement (LGGE) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Université Joseph Fourier - Grenoble 1 Dominique Raynaud |
format |
Doctoral or Postdoctoral Thesis |
author |
Martinerie, Patricia |
author_facet |
Martinerie, Patricia |
author_sort |
Martinerie, Patricia |
title |
Gas content in polar ice. Present geographic variations, variations over the last climatic cycle in the Vostok region. |
title_short |
Gas content in polar ice. Present geographic variations, variations over the last climatic cycle in the Vostok region. |
title_full |
Gas content in polar ice. Present geographic variations, variations over the last climatic cycle in the Vostok region. |
title_fullStr |
Gas content in polar ice. Present geographic variations, variations over the last climatic cycle in the Vostok region. |
title_full_unstemmed |
Gas content in polar ice. Present geographic variations, variations over the last climatic cycle in the Vostok region. |
title_sort |
gas content in polar ice. present geographic variations, variations over the last climatic cycle in the vostok region. |
publisher |
HAL CCSD |
publishDate |
1990 |
url |
https://theses.hal.science/tel-01576069 https://theses.hal.science/tel-01576069/document https://theses.hal.science/tel-01576069/file/Martinerie-PhD-1990.pdf |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
https://theses.hal.science/tel-01576069 Physique [physics]. Université Joseph Fourier - Grenoble 1, 1990. Français. ⟨NNT : ⟩ |
op_relation |
tel-01576069 https://theses.hal.science/tel-01576069 https://theses.hal.science/tel-01576069/document https://theses.hal.science/tel-01576069/file/Martinerie-PhD-1990.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1797584892642459648 |
spelling |
ftunivsavoie:oai:HAL:tel-01576069v1 2024-04-28T08:24:53+00:00 Gas content in polar ice. Present geographic variations, variations over the last climatic cycle in the Vostok region. Teneur en gaz des glaces polaires. Variations géographiques actuelles, variations au cours du dernier cycle climatique dans la région de Vostok. Martinerie, Patricia Laboratoire de glaciologie et géophysique de l'environnement (LGGE) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Université Joseph Fourier - Grenoble 1 Dominique Raynaud 1990-10-22 https://theses.hal.science/tel-01576069 https://theses.hal.science/tel-01576069/document https://theses.hal.science/tel-01576069/file/Martinerie-PhD-1990.pdf fr fre HAL CCSD tel-01576069 https://theses.hal.science/tel-01576069 https://theses.hal.science/tel-01576069/document https://theses.hal.science/tel-01576069/file/Martinerie-PhD-1990.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01576069 Physique [physics]. Université Joseph Fourier - Grenoble 1, 1990. Français. ⟨NNT : ⟩ glaciology climatology air content ice sheets atmospheric pressure paleo elevations porosity glaciologie climatologie teneur en air calottes glaciaires pression atmosphérique paleo altitudes porosité [PHYS]Physics [physics] info:eu-repo/semantics/doctoralThesis Theses 1990 ftunivsavoie 2024-04-11T00:57:53Z Total gas content (V) in polar ice has been used in earlier works as an indicator of ice sheet thickness variations related to climatic change.In this work, a series of experimental tests were performed, which show that the V measurement technique used at LGGE can lead to absolute results within +-1,5% accuracy. A calculation is presented to correct V results from the effect of cut bubbles at the surface of the ice samples, which can lead to gas losses ranging between 1 and 10%.The results from sixteen different drilling sites permit a more detailed description of the present V variations with atmospheric pressure and elevation. This work confirms the pore volume at close-off (Vc) - temperature dependence and do not indicate any clear Vc dependence on snow accumulation. Part of the Vc deviations from linear increase with temperature could be due to the wind influence on Vc.Three different analytical methods were used to investigate total gas content along the two deepest Vostok cores, which cover the last climatic cycle. The different results are consistent and show quick and large amplitude V variations. Constraints imposed by ice sheet dynamics strongly suggest that long term V changes cannot be interpreted only in terms of ice sheet thickness variations. The possible impacts of atmospheric pressure changes and non thermal close-off porosity changes are discussed. La teneur en gaz (V) de la glace a été utilisée dans les travaux antérieurs comme indicateur des variations d'épaisseur des calottes polaires en lien avec les changements du climat.Dans ce travail, une série de tests expérimentaux ont montré que la méthode de mesure de V utilisée au LGGE peut fournir des résultats absolus avec une précision de +- 1,5%. Un calcul est présenté pour corriger les résultats de V de l'effet des bulles coupées en surface des échantillons, qui peut induire des pertes de gaz allant de 1 à 10%.Les résultats concernant 16 sites de forage permettent une description plus détaillée des variations géographiques actuelles de V ... Doctoral or Postdoctoral Thesis Ice Sheet Université Savoie Mont Blanc: HAL |