Extreme 13C depletion of CCl2F2 in firn air samples from NEEM, Greenland

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Zuiderweg, A., Holzinger, R., Martinerie, Patricia, Schneider, R., Kaiser, J., Witrant, Emmanuel, Etheridge, D., Petrenko, V., Blunier, T., Röckmann, T.
• Other Authors: Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University Utrecht, 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), Climate and Environmental Physics Bern (CEP), Physikalisches Institut Bern, Universität Bern Bern (UNIBE)-Universität Bern Bern (UNIBE), School of Environmental Sciences Norwich, University of East Anglia Norwich (UEA), GIPSA - Systèmes linéaires et robustesse (GIPSA-SLR), Département Automatique (GIPSA-DA), Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Centre for Australian Weather and Climate Research, CSIRO Marine and Atmospheric Research, Centre for Australian Weather and Climate Research (CAWCR), Department of Earth and Environmental Sciences Rochester, University of Rochester USA, Centre for Ice and Climate Copenhagen, Niels Bohr Institute Copenhagen (NBI), Faculty of Science Copenhagen, University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Science Copenhagen, University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Greenland; North Greenland
• Online Access: https://hal.archives-ouvertes.fr/hal-00821219; https://hal.archives-ouvertes.fr/hal-00821219/document; https://hal.archives-ouvertes.fr/hal-00821219/file/acp-13-599-2013.pdf; https://doi.org/10.5194/acp-13-599-2013

International audience A series of 12 high volume air samples collected from the S2 firn core during the North Greenland Eemian Ice Drilling (NEEM) 2009 campaign have been measured for mixing ratio and stable carbon isotope composition of the chlorofluorocarbon CFC-12 (CCl 2 F 2). While the mixing ratio measurements compare favorably to other firn air studies, the isotope results show extreme 13 C depletion at the deepest measurable depth (65 m), to values lower than δ 13 C = −80 ‰ vs. VPDB (the international stable carbon isotope scale), compared to present day surface tropospheric measurements near −40 ‰. Firn air modeling was used to interpret these measurements. Reconstructed atmospheric time series indicate even larger depletions (to −120 ‰) near 1950 AD, with subsequent rapid enrichment of the atmospheric reservoir of the compound to the present day value. Mass-balance calculations show that this change is likely to have been caused by a large change in the isotopic composition of anthropogenic CFC-12 emissions, probably due to technological advances in the CFC production process over the last 80 yr, though direct evidence is lacking.