Chemical Sources and Sinks of OCS in the Lower Atmosphere of Venus

Chemical Sources and Sinks of OCS in the Lower Atmosphere of Venus

Yuk L. YungM. C. Liang,

California Institute of Technologyyly@gps.caltech.edu

EGU Meeting2008

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

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S2 OCS

S3 S4S8

hv

S

S

hv

hv

hv

hv

CO

S4

S2

S

S3

S4

hv 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

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