Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 7 6 2007 10.5194/acpd-7-15723-2007 http://www.atmos-chem-phys-discuss.net/7/15723/2007/ http://www.atmos-chem-phys-discuss.net/7/15723/2007/acpd-7-15723-2007.html http://www.atmos-chem-phys-discuss.net/7/15723/2007/acpd-7-15723-2007.pdf 15723 15737 2007-11-09 Long-term observation of mass-independent oxygen isotope anomaly in stratospheric CO₂ S. Kawagucci kawagucci@ori.u-tokyo.ac.jp U. Tsunogai S. Kudo F. Nakagawa H. Honda S. Aoki T. Nakazawa M. Tsutsumi T. Gamo Division of Earth and Planetary Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan Japan Aerospace Exploration Agency, Sagamihara, Japan Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University, Sendai, Japan Department of Chemical Oceanography, Ocean Research Institute, The University of Tokyo, Nakano-ku, Tokyo, Japan Anomalous oxygen isotopic compositions of stratospheric CO₂ were first reported in 1989, although their detailed behavior in the middle atmosphere is still open question. We collected 60 stratospheric air samples over Sanriku, Japan from 1991 to 2004 and Kiruna, Sweden in 1997. Using these accumulated air samples, we performed long-term observations of triple oxygen isotope compositions of stratospheric CO₂. It is the first simultaneous observation in the stratosphere of both relations between Δ¹⁷O_CO2 and [N₂O], and δ¹⁸O_CO2 and δ¹⁷O_CO2, accurately. 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