Teneurs en monoxyde de carbone de l'air contenu dans la glace de l'Antarctique et du Groenland

• Main Author: Haan, Denis
• Other Authors: Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-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 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 I, Dominique Raynaud
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 1996
• Subjects: Sources CO; dosage CO; méthodologie extraction; standards; glaces polaires; historique; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Antarctic; Greenland; Antarc*; Antarctica; Groenland; ice core
• Online Access: https://tel.archives-ouvertes.fr/tel-00754243; https://tel.archives-ouvertes.fr/tel-00754243/document; https://tel.archives-ouvertes.fr/tel-00754243/file/These-Haan-1996.pdf

Carbon monoxide (CO) is one of the most important reactive trace gases in the atmosphere. It is involved in many chemical reactions which affect the atmospheric composition and climate. In this study, we have developed an original method to extract the air trapped in the ice and to analyse its carbon monoxide concentration. The melting refreezing extraction method seems to be the most suitable method for studying carbon monoxide in ice. Blanck tests performed with artificial bubble free ice show that our extraction method do es not lead to any CO contamination as soon as al! impurities have been previously removed from the sampI es surface. It remains difficult to assess how representative are these tests in the case of natural ice from Greenland and Antarctica. Nevertheless, we show that antarctic ice exhibits a similar behaviour as artificial ice during a melting refreezing cycle. Concerning the Greenland ice, it appears to be more complex because it seems to indu ce other CO contamination mostly linked to chemical CO production processes occuring within the ice. The melting refreezing method has been applied to ice core samples originating from Antarctica and Greenland. For the first time, consistent results in terms of atmospheric concentrations have been obtained. A CO increase of about 20% has been recorded in the Eurocore ice core for the period 1850-1950 A.D, in good correlation with anthropogenic CO source (like coal and petrol consumption) changes that have occured during the same period. By contrast, CO levels observed on Antarctic ice (D47 ice core) exhibit no significant change during the period 1860-1920 A.D. This suggests that Antarctica remained under the influence of natural CO sources during this period. In terms of CO cycle, our results suggest that anthropogenic CO sources could have already been existing during the preindustrial period. This will represent an important constrain for future model simulations. Apart from these results, the study of the deeper part of the Eurocore ice core ...