Back

Title
  • en Long-term observation of mass-independent oxygen isotope anomaly in stratospheric CO2
Creator
    • en Kawagucci, S.
    • en Kudo, S.
    • en Nakagawa, F.
    • en Honda, H.
    • en Aoki, S.
    • en Nakazawa, T.
    • en Tsutsumi, M.
    • en Gamo, T.
Accessrights open access
Subject
  • NDC 450
Description
  • Abstract en Stratospheric and upper tropospheric air samples were collected during 1994?2004 over Sanriku, Japan and in 1997 over Kiruna, Sweden. Using these archived air samples, we determined the triple oxygen-isotope composition of stratospheric CO2 and the N2O mixing ratio. The maximum Δ17OCO2 value of +12.2‰, resembling that observed previously in the mesosphere at 60 km height, was found in the middle stratosphere over Kiruna at 25.6 km height, suggesting that upper stratospheric and mesospheric air descended to the middle stratosphere through strong downward advection. A least-squares regression analysis of our observations on a δ18OCO2?δ17OCO2 plot (r2>0.95) shows a slope of 1.63±pm0.10, which is similar to the reported value of 1.71±0.06, thereby confirming the linearity of three isotope correlation with the slope of 1.6?1.7 in the mid-latitude lower and middle stratosphere. The slope decrease with increasing altitude and a curvy trend in three-isotope correlation reported from previous studies were not statistically significant. Using negative linear correlations of Δ17OCO2 and δ18OCO2 with the N2O mixing ratio, we quantified triple oxygen-isotope fluxes of CO2 to the troposphere as +48‰ GtC/yr (Δ17OCO2) and +38‰ GtC/yr (δ18OCO2) with ~30% uncertainty. Comparing recent model results and observations, underestimation of the three isotope slope and the maximum Δ17OCO2 value in the model were clarified, suggesting a smaller O2 photolysis contribution than that of the model. Simultaneous observations of δ18OCO2, δ17OCO2, and N2O mixing ratios can elucidate triple oxygen isotopes in CO2 and clarify complex interactions among physical, chemical, and photochemical processes occurring in the middle atmosphere.
Publisher en Copernicus Publications
Date
    Issued2008-10-24
Language
  • eng
Resource Type journal article
Version Type VoR
Identifier HDL http://hdl.handle.net/2115/44836
Relation
  • isIdenticalTo DOI https://doi.org/10.5194/acp-8-6189-2008
Journal
    • PISSN 1680-7316
    • EISSN 1680-7324
    • NCID AA12038447
      • en Atmospheric Chemistry and Physics
      • Volume Number8 Issue Number20 Page Start6189 Page End6197
File
Oaidate 2023-07-26