HR: 1340h
AN: B43D-1579    [Abstracts]
TI: Surface CO2 Isotopologues: Influence of Stratosphere-Troposphere Exchange
AU: * Liang, M
EM: mcl@rcec.sinica.edu.tw
AF: Research Center for Environmental Changes, Academia Sinica, 128 Sec. 2, Academia Rd., Nankang, Taipei, 115, Taiwan
AU: Chan, Z
EM: chzy@mail.sysu.edu.cn
AF: School of Environmental Science & Engineering Sun Yat-Sen University, 135 Xingang West Road, Guangzhou, 510275, China
AU: Tang, J
EM: tangj@cams.cma.gov.cn
AF: Key Laboratory of Atmospheric Chemistry/CMA, Chinese Academy of Meteorological Sciences, No.46, Zhong Guancun Nan Dajie, Haidian, Beijing, 100081, China
AU: Zheng, X
EM: zhengxd@cams.cma.gov.cn
AF: Key Laboratory of Atmospheric Chemistry/CMA, Chinese Academy of Meteorological Sciences, No.46, Zhong Guancun Nan Dajie, Haidian, Beijing, 100081, China
AU: Yung, Y
EM: yly@gps.caltech.edu
AF: Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, United States
AB: Current estimates of gross carbon flux tend to ignore the downwelling flux of CO₂ from the stratosphere, through the downward branch of Brewer-Dobson circulation at high latitudes. Recent observations showed that there is a phase shift between a time series for the concentration of the standard isotopologue C¹⁶O¹⁶O and that for C¹⁶O¹⁸O at the surface at Waliguan, China (36 17' N, 100 54' E, 3810 m). Using a 2-dimensional model of the troposphere and stratosphere, we show that this phase shift could be explained by the downwelling of CO₂ from the stratosphere, where C¹⁶O¹⁸O is known to be enriched. Using O3 as a proxy of stratosphere-troposphere exchange, we find there is excellent correlation between O3 and C¹⁶O¹⁸O observed at the Waliguan site. The observed variability of C¹⁶O¹⁸O is consistent with the predictions of our model, thus providing the first evidence of stratospheric CO₂ near the surface. 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.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 0428 Carbon cycling (4806)
DE: 0454 Isotopic composition and chemistry (1041, 4870)
DE: 1704 Atmospheric sciences
SC: Biogeosciences [B]
MN: 2007 Fall Meeting