Letter | Published:

Photolysis of sulphuric acid as the source of sulphur oxides in the mesosphere of Venus

Nature Geoscience volume 3, pages 834837 (2010) | Download Citation

Subjects

Abstract

The sulphur cycle plays fundamental roles in the chemistry1,2,3 and climate4,5 of Venus. Thermodynamic equilibrium chemistry at the surface of Venus favours the production of carbonyl sulphide6 and to a lesser extent sulphur dioxide. These gases are transported to the middle atmosphere by the Hadley circulation cell7,8. Above the cloud top, a sulphur oxidation cycle involves conversion of carbonyl sulphide into sulphur dioxide, which is then transported further upwards. A significant fraction of this sulphur dioxide is subsequently oxidized to sulphur trioxide and eventually reacts with water to form sulphuric acid3. Because the vapour pressure of sulphuric acid is low, it readily condenses and forms an upper cloud layer at altitudes of 60–70 km, and an upper haze layer above 70 km (ref. 9), which effectively sequesters sulphur oxides from photochemical reactions. Here we present simulations of the fate of sulphuric acid in the Venusian mesosphere based on the Caltech/JPL kinetics model3,10, but including the photolysis of sulphuric acid. Our model suggests that the mixing ratios of sulphur oxides are at least five times higher above 90 km when the photolysis of sulphuric acid is included. Our results are inconsistent with the previous model results but in agreement with the recent observations using ground-based microwave spectroscopy11 and by Venus Express12.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    , & in Exploring Venus as a Terrestrial Planet (eds Esposito, L. W., Stofan, E. R. & Cravens, T. E.) 73–100 (Am. Geophys. Union, 2007).

  2. 2.

    Venus: Composition and structure of the visible clouds. Science 182, 1132–1135 (1973).

  3. 3.

    & Photochemistry of the stratosphere of Venus: Implications for atmospheric evolution. Icarus 51, 199–247 (1982).

  4. 4.

    & in Venus II: Geology, Geophysics, Atmosphere, and Solar Wind Environment (eds Bougher, S. W., Hunten, D. M. & Philips, R. J.) 353–384 (Univ. Arizona Press, 1997).

  5. 5.

    & Stabilization of Venus’ climate by a chemical–albedo feedback. Earth Planet. Space 52, 197–202 (2000).

  6. 6.

    & Formation of carbonyl sulfide (OCS) from carbon monoxide and sulfur vapor and applications to Venus. Icarus 130, 495–504 (1997).

  7. 7.

    & The atmospheres of Venus, Earth, and Mars—a critical comparison. Annu. Rev. Earth Planet. Sci. 15, 171–212 (1987).

  8. 8.

    et al. Evidence for carbonyl sulfide (OCS) conversion to CO in the lower atmosphere of Venus. J. Geophys. Res. 114, E00B34 (2009).

  9. 9.

    , , , & in Venus (eds Hunten, D. M., Colin, L., Donahue, T. M. & Moroz, V. I.) 484–564 (Univ. Arizona Press, 1983).

  10. 10.

    I. Observations and Photochemical Modeling of the Venus Middle Atmosphere. II. Thermal Infrared Spectroscopy of Europa and Callisto. PhD thesis, California Inst. Technology 1–277 (1998).

  11. 11.

    , , & Sulfur chemistry in the Venus mesosphere from SO2 and SO microwave spectra. Icarus 208, 49–60 (2010).

  12. 12.

    et al. Vertical profiling of SO2 above Venus’ clouds by means of SPICAV/SOIR occultations. Bull. Am. Astron. Soc. 41, 1120–1120 (2009).

  13. 13.

    et al. First observations of SO2 above Venus’ clouds by means of solar occultation in the infrared. J. Geophys. Res. 113, E00B25 (2008).

  14. 14.

    et al. in Exploring Venus as a Terrestrial Planet (eds Esposito, L. W., Stofan, E. R. & Cravens, T. E.) 101–120 (Am. Geophys. Union, 2007).

  15. 15.

    et al. Recent hot-spot volcanism on Venus from VIRTIS emissivity data. Science 328, 605–608 (2010).

  16. 16.

    , & Volcanic Eruptions from Linear Vents on Earth, Venus and Mars: Comparisons with Central Vent Eruptions (41st Lunar and Planetary Science Conference).1147–1148 (2010).

  17. 17.

    et al. Photolysis of sulfuric acid vapor by visible light as a source of the polar stratospheric CN layer. J. Geophys. Res. 110, D08201 (2005).

  18. 18.

    Vapor pressure of pure substances—inorganic compounds. Ind. Eng. Chem. 39, 540–550 (1947).

  19. 19.

    & Calculated electronic transitions in sulfuric acid and implications for its photodissociation in the atmosphere. J. Phys. Chem. A 112, 4958–4964 (2008).

  20. 20.

    , , & Photolysis of sulfuric acid vapor by visible solar radiation. Science 299, 1566–1568 (2003).

  21. 21.

    et al. A warm layer in Venus’ cryosphere and high-altitude measurements of HF, HCl, H2O and HDO. Nature 450, 646–649 (2007).

  22. 22.

    , & The search for sulfuric acid. J. Phys. Chem. A 107, 2025–2032 (2003).

  23. 23.

    , , , & A one-dimensional model describing aerosol formation and evolution in the stratosphere: II. Sensitivity studies and comparison with observations. J. Atmos. Sci. 36, 718–736 (1979).

  24. 24.

    Atmospheric aerosol and cloud condensation nuclei formation: A possible influence of cosmic rays? Space Sci. Rev. 125, 169–186 (2006).

  25. 25.

    & Microphysics of Venusian clouds in rising tropical air. J. Atmos. Sci. 58, 3597–3612 (2001).

  26. 26.

    & Dynamics of vibrational overtone excitations of H2SO4, H2SO4–H2O: Hydrogen-hopping and photodissociation processes. J. Am. Chem. Soc. 128, 9594–9595 (2006).

  27. 27.

    , & The ultraviolet absorber on Venus—amorphous sulfur. Icarus 51, 358–373 (1982).

  28. 28.

    Venus’ Ultraviolet Absorber and Sulfuric Acid Droplets. International Venus Conference, Aussois, France, 4–4 (2010).

  29. 29.

    Albedo enhancement by stratospheric sulfur injections: A contribution to resolve a policy dilemma? Clim. Change 77, 211–219 (2006).

  30. 30.

    et al. On geoengineering with sulphate aerosols in the tropical upper troposphere and lower stratosphere. Clim. Change 90, 315–331 (2008).

Download references

Acknowledgements

We thank V. Vaida, F. W. Taylor, S. E. Smrekar, F. W. DeMore and O. B. Toon for comments and M. Gerstell, N. Heavens, R. L. Shia and M. Line for reading the manuscipt. This research was supported by NASA grant NNX07AI63G to the California Institute of Technology. M-C.L. was supported by NSC grant 98-2111-M-001-014-MY3 to Academia Sinica.

Author information

Affiliations

  1. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, 91125, USA

    • Xi Zhang
    •  & Yuk L. Yung
  2. Research Center for Environmental Changes, Academia Sinica, Taipei 11529, Taiwan

    • Mao-Chang Liang
  3. Graduate Institute of Astronomy, National Central University, Zhongli 32001, Taiwan

    • Mao-Chang Liang
  4. Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan

    • Mao-Chang Liang
  5. LATMOS, CNRS/INSU/IPSL, Université de Versailles-Saint-Quentin, Quartier des Garennes, 78280 Guyancourt, France

    • Franck Montmessin
    •  & Jean-Loup Bertaux
  6. Université Pierre et Marie Curie, 75252, Paris, France

    • Franck Montmessin
    •  & Jean-Loup Bertaux
  7. Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, Michigan 48109, USA

    • Christopher Parkinson

Authors

  1. Search for Xi Zhang in:

  2. Search for Mao-Chang Liang in:

  3. Search for Franck Montmessin in:

  4. Search for Jean-Loup Bertaux in:

  5. Search for Christopher Parkinson in:

  6. Search for Yuk L. Yung in:

Contributions

X.Z., Y.L.Y., C.P. and F.M. contributed to the paper writing. X.Z. carried out the modelling work; M-C.L. helped with the modelling; F.M. and J-L.B. provided the data from the SPICAV instrument on board Venus Express; C.P. provided critical evaluation of the H2SO4 photolysis data; Y.L.Y. conceived and supervised the research.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Xi Zhang.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Information

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/ngeo989

Further reading