A Caltech Library Service

Photochemistry of the Stratosphere of Venus: Implications for Atmospheric Evolution

Yung, Yuk L. and DeMore, W. B. (1982) Photochemistry of the Stratosphere of Venus: Implications for Atmospheric Evolution. Icarus, 51 (2). pp. 199-247. ISSN 0019-1035. doi:10.1016/0019-1035(82)90080-X.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


The photochemistry of the stratosphere of Venus was modeled using an updated and expanded chemical scheme, combined with the results of recent observations and laboratory studies. We examined three models, with H2 mixing ratio equal to 2 × 10^(−5), 5 × 10^(−7), and 1 × 10^(−13), respectively. All models satisfactorily account for the observations of CO, O_2, O_2(^1Δ), and SO_2 in the stratosphere, but only the last one may be able to account for the diurnal behavior of mesospheric CO and the uv albedo. Oxygen, derived from CO_2 photolysis, is primarily consumed by CO_2 recombination and oxidation of SO_2 to H_2SO_4. Photolysis of HCl in the upper stratosphere provides a major source of odd hydrogen and free chlorine radicals, essential for the catalytic oxidation of CO. Oxidation of SO_2 by O occurs in the lower stratosphere. In the high-H_2 model (model A) the O-O bond is broken mainly by S + O_2 and SO + HO_2. In the low-H_2 models additional reactions for breaking the O-O bond must be invoked: NO + HO_2 in model B and ClCO + O_2 in model C. It is shown that lightning in the lower atmosphere could provide as much as 30 ppb of NO_x in the stratosphere. Our modeling reveals a number of intriguing similarities, previously unsuspected, between the chemistry of the stratosphere of Venus and that of the Earth. Photochemistry may have played a major role in the evolution of the atmosphere. The current atmosphere, as described by our preferred model, is characterized by an extreme deficiency of hydrogen species, having probably lost the equivalent of 10^2–10^3 times the present hydrogen content.

Item Type:Article
Related URLs:
URLURL TypeDescription
Yung, Yuk L.0000-0002-4263-2562
Additional Information:© 1982 by Academic Press, Inc. Received November 13, 1981; revised March 1, 1982. Available online 26 October 2002. Paper presented at "An International Conference on the Venus Environment," Palo Alto, California, November l-6, 1981. Contribution No. 3692 of the Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125. We thank J. J. Margitan, S. H. Jaffe, L. Phillips, K. S. Bhatki, M. Patapoff, M. T. Leu, C. J. Howard, L. W. Esposito, D. 0. Muhleman, and R. T. Clancy for communication of experimental data prior to publication. We benefited from helpful discussions with M. B. McElroy, R. G. Prinn, D. M. Hunten, S. Kumar, T. M. Donahue,J. Blamont, 0. B. Toon, W. T. Huntress, Jr., M. Allen, and J.P. Pinto, and critical comments given by the referees Drs. S. C. Wofsy and V. A. Krasnopolsky. This research was supported by NASA Ames Research Center Grant NCC 2-61 to California Institute of Technology. This also represented one phase of NASA-sponsored research carried out at the Jet Propulsion Laboratory under Contract NAS7-100.
Group:UNSPECIFIED, Division of Geological and Planetary Sciences
Funding AgencyGrant Number
NASA Ames Research Center GrantNCC 2-61
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences3692
Issue or Number:2
Record Number:CaltechAUTHORS:20140819-151226643
Persistent URL:
Official Citation:Yuk L. Yung, W.B. Demore, Photochemistry of the stratosphere of Venus: Implications for atmospheric evolution, Icarus, Volume 51, Issue 2, August 1982, Pages 199-247, ISSN 0019-1035, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48696
Deposited By: Ruth Sustaita
Deposited On:19 Aug 2014 22:29
Last Modified:10 Nov 2021 18:34

Repository Staff Only: item control page