L'air piégé dans les glaces polaires: Contraintes chronologiques et caractérisation de la variabilité climatique rapide
Polar regions are particularly sensitive to the present climate change because of amplification mechanisms at play. Ice cores from Antarctica and Greenland provide precious archives of paleoclimatic variations at these high latitudes but also provide information on environmental changes at lower lat...
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Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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2010
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Online Access: | https://tel.archives-ouvertes.fr/tel-00579600 https://tel.archives-ouvertes.fr/tel-00579600/document https://tel.archives-ouvertes.fr/tel-00579600/file/memoire-these-CAPRON.pdf |
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ftccsdartic:oai:HAL:tel-00579600v1 2023-05-15T13:50:10+02:00 L'air piégé dans les glaces polaires: Contraintes chronologiques et caractérisation de la variabilité climatique rapide Capron, Emilie Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) Université de Versailles-Saint Quentin en Yvelines Valérie Masson-Delmotte 2010-09-27 https://tel.archives-ouvertes.fr/tel-00579600 https://tel.archives-ouvertes.fr/tel-00579600/document https://tel.archives-ouvertes.fr/tel-00579600/file/memoire-these-CAPRON.pdf fr fre HAL CCSD tel-00579600 https://tel.archives-ouvertes.fr/tel-00579600 https://tel.archives-ouvertes.fr/tel-00579600/document https://tel.archives-ouvertes.fr/tel-00579600/file/memoire-these-CAPRON.pdf info:eu-repo/semantics/OpenAccess https://tel.archives-ouvertes.fr/tel-00579600 Climatologie. Université de Versailles-Saint Quentin en Yvelines, 2010. Français air isotopes Antarctica bipolar seesaw pattern climatic variability at millennial and sub-millennial scale dating firn glacial period Greenland last glacial inception ice core methane Antarctique carotte de glace Dansgaard-Oeschger datation entrée en glaciation Groenland instabilités climatiques abruptes isotopes de l'air méthane névé période glaciaire bascule bipolaire paléoclimat [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology info:eu-repo/semantics/doctoralThesis Theses 2010 ftccsdartic 2021-12-19T03:40:57Z Polar regions are particularly sensitive to the present climate change because of amplification mechanisms at play. Ice cores from Antarctica and Greenland provide precious archives of paleoclimatic variations at these high latitudes but also provide information on environmental changes at lower latitudes. This work takes advantage of information inferred from the air trapped in ice: the elemental and isotopic composition of air (N2, O2, Ar and Kr) and the methane concentration. Our results provide new insights on three different issues: (i) Past dynamic of Antarctic firn. Measurements of krypton isotopes provide direct evidences for the presence of a deep convective zone (20-50m) in the firn at Dome C during glacial periods. Based on nitrogen isotopic profiles ("15N) from EPICA Dronning Maud Land (EDML) and TALDICE ice cores, we suggest that the evolution of the firn structure is mainly controlled by accumulation rate only below a threshold in accumulation defined at 5 ±1.5 cm ice equivalent yr-1. (ii) Ice core dating. We present the first record of #O2/N2 over the EDC ice core covering the period between 300 and 800 ka. Even if we call for cautiousness in the use of this parameter as an orbital dating tool during periods characterized by a low eccentricity, the "O2/N2 is a useful tool to test the current EDC3 chronology. By coupling the isotopic composition of atmospheric oxygen and methane concentration, we synchronise the EDML (Antarctica) and NorthGRIP (Greenland) ice cores between 75 000 and 123 000 years with an associated uncertainty smaller than 400 years. (iii) This common timescale enables us to depict the abrupt climatic variability at the beginning of the last glacial period. We evidence sub-millennial scale climatic variations superimposed to the classical Dansgaard-Oeschger (DO) event succession, i.e. precursor-type peak events preceding some DO events and rebound-type climatic events at the end of the interstadial phase. We demonstrate that the bipolar seesaw pattern between Antarctica and ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctica Antarctique* Dronning Maud Land EPICA Greenland Greenland ice cores Groenland ice core Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Antarctic Dronning Maud Land Greenland |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
French |
topic |
air isotopes Antarctica bipolar seesaw pattern climatic variability at millennial and sub-millennial scale dating firn glacial period Greenland last glacial inception ice core methane Antarctique carotte de glace Dansgaard-Oeschger datation entrée en glaciation Groenland instabilités climatiques abruptes isotopes de l'air méthane névé période glaciaire bascule bipolaire paléoclimat [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
spellingShingle |
air isotopes Antarctica bipolar seesaw pattern climatic variability at millennial and sub-millennial scale dating firn glacial period Greenland last glacial inception ice core methane Antarctique carotte de glace Dansgaard-Oeschger datation entrée en glaciation Groenland instabilités climatiques abruptes isotopes de l'air méthane névé période glaciaire bascule bipolaire paléoclimat [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology Capron, Emilie L'air piégé dans les glaces polaires: Contraintes chronologiques et caractérisation de la variabilité climatique rapide |
topic_facet |
air isotopes Antarctica bipolar seesaw pattern climatic variability at millennial and sub-millennial scale dating firn glacial period Greenland last glacial inception ice core methane Antarctique carotte de glace Dansgaard-Oeschger datation entrée en glaciation Groenland instabilités climatiques abruptes isotopes de l'air méthane névé période glaciaire bascule bipolaire paléoclimat [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
description |
Polar regions are particularly sensitive to the present climate change because of amplification mechanisms at play. Ice cores from Antarctica and Greenland provide precious archives of paleoclimatic variations at these high latitudes but also provide information on environmental changes at lower latitudes. This work takes advantage of information inferred from the air trapped in ice: the elemental and isotopic composition of air (N2, O2, Ar and Kr) and the methane concentration. Our results provide new insights on three different issues: (i) Past dynamic of Antarctic firn. Measurements of krypton isotopes provide direct evidences for the presence of a deep convective zone (20-50m) in the firn at Dome C during glacial periods. Based on nitrogen isotopic profiles ("15N) from EPICA Dronning Maud Land (EDML) and TALDICE ice cores, we suggest that the evolution of the firn structure is mainly controlled by accumulation rate only below a threshold in accumulation defined at 5 ±1.5 cm ice equivalent yr-1. (ii) Ice core dating. We present the first record of #O2/N2 over the EDC ice core covering the period between 300 and 800 ka. Even if we call for cautiousness in the use of this parameter as an orbital dating tool during periods characterized by a low eccentricity, the "O2/N2 is a useful tool to test the current EDC3 chronology. By coupling the isotopic composition of atmospheric oxygen and methane concentration, we synchronise the EDML (Antarctica) and NorthGRIP (Greenland) ice cores between 75 000 and 123 000 years with an associated uncertainty smaller than 400 years. (iii) This common timescale enables us to depict the abrupt climatic variability at the beginning of the last glacial period. We evidence sub-millennial scale climatic variations superimposed to the classical Dansgaard-Oeschger (DO) event succession, i.e. precursor-type peak events preceding some DO events and rebound-type climatic events at the end of the interstadial phase. We demonstrate that the bipolar seesaw pattern between Antarctica and ... |
author2 |
Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) Université de Versailles-Saint Quentin en Yvelines Valérie Masson-Delmotte |
format |
Doctoral or Postdoctoral Thesis |
author |
Capron, Emilie |
author_facet |
Capron, Emilie |
author_sort |
Capron, Emilie |
title |
L'air piégé dans les glaces polaires: Contraintes chronologiques et caractérisation de la variabilité climatique rapide |
title_short |
L'air piégé dans les glaces polaires: Contraintes chronologiques et caractérisation de la variabilité climatique rapide |
title_full |
L'air piégé dans les glaces polaires: Contraintes chronologiques et caractérisation de la variabilité climatique rapide |
title_fullStr |
L'air piégé dans les glaces polaires: Contraintes chronologiques et caractérisation de la variabilité climatique rapide |
title_full_unstemmed |
L'air piégé dans les glaces polaires: Contraintes chronologiques et caractérisation de la variabilité climatique rapide |
title_sort |
l'air piégé dans les glaces polaires: contraintes chronologiques et caractérisation de la variabilité climatique rapide |
publisher |
HAL CCSD |
publishDate |
2010 |
url |
https://tel.archives-ouvertes.fr/tel-00579600 https://tel.archives-ouvertes.fr/tel-00579600/document https://tel.archives-ouvertes.fr/tel-00579600/file/memoire-these-CAPRON.pdf |
geographic |
Antarctic Dronning Maud Land Greenland |
geographic_facet |
Antarctic Dronning Maud Land Greenland |
genre |
Antarc* Antarctic Antarctica Antarctique* Dronning Maud Land EPICA Greenland Greenland ice cores Groenland ice core |
genre_facet |
Antarc* Antarctic Antarctica Antarctique* Dronning Maud Land EPICA Greenland Greenland ice cores Groenland ice core |
op_source |
https://tel.archives-ouvertes.fr/tel-00579600 Climatologie. Université de Versailles-Saint Quentin en Yvelines, 2010. Français |
op_relation |
tel-00579600 https://tel.archives-ouvertes.fr/tel-00579600 https://tel.archives-ouvertes.fr/tel-00579600/document https://tel.archives-ouvertes.fr/tel-00579600/file/memoire-these-CAPRON.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766253167617507328 |