Isotopic constraints on non-photochemical sulfate production in the Arctic winter

• Published in: Geophysical Research Letters
• Main Authors: Mccabe, Justin R., Savarino, Joel, Alexander, Becky, Gong, Sunling, H. Thiemens, Mark
• Other Authors: Department of Chemistry and Biochemistry, University of California Los Angeles (UCLA), University of California (UC)-University of California (UC), 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), Department of Atmospheric Sciences Seattle, University of Washington Seattle, Air Quality Research Branch, Meteorological Service of Canada, Environment and Climate Change Canada
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: Aerosols; Particles; Stable isotope geochemistry; Biogeochemical cycles processes and modeling; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Arctic; Canada
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-00375726; https://hal-insu.archives-ouvertes.fr/insu-00375726/document; https://hal-insu.archives-ouvertes.fr/insu-00375726/file/2005GL025164.pdf; https://doi.org/10.1029/2005GL025164

International audience The oxygen isotopic composition (Δ17O) of non-seasalt sulfate (NSS) aerosol was measured in samples from Alert, Canada over one year (July 1999–June 2000) and used to quantify the S(IV) oxidants. Measurements of Δ17O in NSS are used to evaluate the relative contributions of O3, H2O2, and OH oxidation leading to the formation of SO4 2− compared to a model of Feichter et al. (1996). The isotopic values suggest that there is a twofold overestimate of ozone oxidation in the model during winter. The isotopic composition is consistent with 10 to 18% contribution from a non-photochemical oxidation pathway, likely Fe3+/Mn2+-catalyzed O2 oxidation, during the dark Arctic winter. Isotopic evidence also invokes a 3 to 10% contribution of a mass dependent oxidant during springtime Arctic ozone depletion events.