P.O. Wennberg, J.W. Brault, T.F. Hanisco, R.J. Salawitch and George H. Mount.

J. Geophys. Res., 102, 8887-8898, 1997.

Abstract

Absorption attributable to atmospheric IO is observed in high resolution, high airmass solar spectra taken at the National Solar Observatory, Kitt Peak, Arizona in March, 1995. These observations, together with the effective cross sections determined from the pressure and lifetime broadened lineshapes measured in the laboratory for the IO {A 2P 3/2¬ X 2P 3/2 (2,0)} rotationally-resolved electronic transition (near 445 nm), are consistent with a total stratospheric iodine mixing ratio of 0.2 ± ^0.3_0.2 pptv. This result, combined with recent laboratory measurements of the rate of the reactions of IO with other halogen species, suggests that iodine chemistry is not responsible for the trends observed in lower stratospheric ozone.