The photochemistry of stratospheric ozone

A short review of the photochemical theory in a ‘dry’ atmosphere is given. It is shown that the difference between theory and observations concerning the vertical gradient of n 3 (molecules of ozone/cm 3 ) in the upper stratosphere, where photochemical equilibrium may be assumed, can hardly be accounted for by observational uncertainties. It seems, however, not impossible to reconcile theory and observations by parametric adjustment. A semi‐quantitative theory of ozone in a ‘wet’ stratosphere is developed and the relative importance of different types of reactions is discussed. No reliable quantitative conclusion can be drawn at present due to large uncertainties in a number of parameters. In comparing vertical ozone distribution from this theory with observational data and considering the resulting change in relaxation times compared to the ‘classical’ theory, it is concluded that the influence of reactions of O and O 3 with active hydrogen compounds cannot be as strong as that derived from the use of Hunt's reaction rates.