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Chemical Sources and Sinks of OCS in the Lower Atmosphere of Venus. Yuk L. Yung M. C. Liang, California Institute of Technology yly@gps.caltech.edu EGU Meeting 2008. Important Processes in the Atmosphere of Venus. Catalytic Chemical Cycles Heterogeneous Chemistry
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Chemical Sources and Sinks of OCS in the Lower Atmosphere of Venus Yuk L. Yung M. C. Liang, California Institute of Technology yly@gps.caltech.edu EGU Meeting 2008
Important Processes in the Atmosphere of Venus • Catalytic Chemical Cycles • Heterogeneous Chemistry • Middle Atmosphere Circulation • OCS as tracers of chemistry and dynamics
Venus model description • Two-dimensional Caltech/JPL KINETICS chemical transport model • Solve continuity equation for 24 species with ~200 chemical reactions (subset of Mills’)
Role of circulation • Affect the upward flux of OCS from the surface • Reduce OCS abundances at high latitudes
S hv S2 S S3 OCS S4 CO hv hv S hv hv S2 S3 hv S4 S8 S4 S
Conclusions • Scale height of OCS cannot be explained by photolysis alone • Photosensitized dissociation of OCS via polysulfur photochemistry • Integrated destruction rate of OCS is 23,000 Tg- S/yr [Earth = 10 Tg-S/yr]
Acknowledgements • NASA and ESA • P. Drossart • R. L. Shia • K. Baines • D. Crisp • C. Lee • X. Jiang • B. Bezard • E. Marq