Signature of stratospheric air at the Tibetan Plateau

• Published in: Geophysical research letters 2008-10, Vol.35 (20), p.n/a
• Main Authors: Liang, Mao-Chang, Tang, J., Chan, Chuen-Yu, Zheng, X. D., Yung, Yuk L.
• Format: Article
• Language: English
• Subjects: CO2 sources and sinks; Earth sciences; Earth, ocean, space; Exact sciences and technology
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2008GL035246

Current estimates of gross carbon flux tend to ignore the downwelling flux of CO2 from the stratosphere. Observations showed that there is a phase shift between the time series for the concentration of the standard isotopologue C16O16O and C16O18O at Waliguan, China (36°17′N, 100°54′E, 3816 m) and several other places. Previous attempts to explain the shift have not been satisfactory. Here we show that the phase shift could be explained by the downwelling air from the stratosphere, and demonstrate that this source of CO2 provides a useful tool for constraining the carbon cycle. Using O3 as a proxy of stratosphere‐troposphere exchange, we find excellent correlation between O3 and C16O18O observed at the Waliguan Observatory. The observed variability of C16O18O is consistent with model predictions, thus supporting that the surface air has significant contributions from the stratosphere. Quantitative modeling may provide a powerful tool for constraining the sources and sinks of CO2 using the isotopically enriched CO2 from the stratosphere as a tracer.