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

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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

Not Used