|
|
Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Science / Faculty of Science >
Peer-reviewed Journal Articles, etc >
Long-term observation of mass-independent oxygen isotope anomaly in stratospheric CO2
| Title: | Long-term observation of mass-independent oxygen isotope anomaly in stratospheric CO2 |
| Authors: | Kawagucci, S. Browse this author | | Tsunogai, U. Browse this author →KAKEN DB | | Kudo, S. Browse this author | | Nakagawa, F. Browse this author | | Honda, H. Browse this author | | Aoki, S. Browse this author | | Nakazawa, T. Browse this author | | Tsutsumi, M. Browse this author | | Gamo, T. Browse this author |
| Issue Date: | 24-Oct-2008 |
| Publisher: | Copernicus Publications |
| Journal Title: | Atmospheric Chemistry and Physics |
| Volume: | 8 |
| Issue: | 20 |
| Start Page: | 6189 |
| End Page: | 6197 |
| Publisher DOI: | 10.5194/acp-8-6189-2008 |
| Abstract: | 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. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/44836 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
|
Submitter: 角皆 潤
|
