Rate of Formation of the ClO Dimer in the Polar Stratosphere: Implications for Ozone Loss

• Published in: Science
• Main Authors: Sander, Stanley P., Friedl, Randall R., Yung, Yuk L.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Association for the Advancement of Science 1989
• Subjects: Antarc*; Antarctic
• Online Access: https://doi.org/10.1126/science.245.4922.1095

The gas-phase recombination of chlorine monoxide (ClO) has been investigated under the conditions of pressure and temperature that prevail in the Antarctic stratosphere during the period of maximum ozone (O_3) disappearance. Measured rate constants are less than one-half as great as the previously accepted values. One-dimensional model calculations based on the new rate data indicate that currently accepted chemical mechanisms can quantitatively account for the observed O_3 losses in late spring (17 September to 7 October). A qualitative assessment indicates that the existing mechanisms can only account for at most one-half of the measured O3 depletion in the early spring (28 August to 17 September), indicating that there may be additional catalytic cycles, besides those currently recognized, that destroy O_3. © 1989 American Association for the Advancement of Science. Received 29 March 1989; accepted 12 July 1989. Part of the research described in this report was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA). Y.L.Y. was supported by NASA grant NAGW-413 to the California Institute of Technology. We acknowledge several valuable conversations with M. Allen, W. DeMore, C. B. Farmer, J. Margitan, M. Molina, J. Rodriguez, G. Toon, and J. Sander. We thank D. Hofmann, R. DeZafra, R. Schindler, C. B. Farmer, C. Howard, D. McKenna, and D. Hartmann for preprints.