Enregistrements climatiques à Law Dome : variabilité pour les périodes récentes et pour la déglaciation

• Main Author: Delmotte, Marc
• Other Authors: 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 I, Dominique Raynaud; Jean Jouzel
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 1997
• Subjects: experimentation; isotopes oxygène; fonction de transfert; Antarctique; forages; Holocène; dernière déglaciation; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Antarc*; Antarctic; Antarctica; Antarctique*; East Antarctica; ice core
• Online Access: https://theses.hal.science/tel-00759854; https://theses.hal.science/tel-00759854/document; https://theses.hal.science/tel-00759854/file/These-Delmotte-1997.pdf

The complexity of the climate system means that for the reconstruction of past variations, the use of a multiplicity of proxy indicators is mandatory. Polar ice cores provide a unique source of proxy data because of the variety of indicators which can be obtained by different analyses. This study concentrates on analysis of the isotopic composition and the total air content in the DSS (Dome Summit South) ice core drilled on Law Dome in coastal East Antarctica. The number of analyses and the precision required for the isotopic measurements in a deep polar core study require specific adaptation of classical mass spectrometer techniques. This study presents a new and original sample injection technique which when used in conjunction with an existing mass spectrometer allowed a significant increase in efficiency without affecting the measurement accuracy. Recent studies have questioned the quantitative interpretation of isotope ratio in terms of temperature. In this study of new surface snow samples from Eastern Antarctica we discuss the validity of the spatial isotope/temperature relationship and suggest an estimation of the associated uncertainty. The combined use of deuterium excess data with simulations of a simple isotopic model are also used to give additional information on the origin of the precipitation. In order to understand recent climatic changes, it is essential to place them in the context of climatic natural variability. The unique temporal resolution of the DSS core allows us to study the climate of the last 4,000 years in exceptional detail. Spectral analysis of the record suggests the existence of oscillating modes linked with the ENSO and/or the Antarctic Circumpolar Wave. Finally, analysis of DSS samples for air content provides complementary information about the elevation variation probably encountered by the LawDome during the last climatie transition. La complexité du système climatique nécessite de recourir à une grande variété d'indicateurs pour reconstruire ses variations passées. A ce ...