Photochemistry of ozone in a moist atmosphere

Abstract

A detailed investigation has been made into the photochemistry of ozone in an atmosphere containing hydrogen. It is shown that for such an atmosphere a satisfactory ozone profile can be obtained, unlike the situation now existing for an oxygen only atmosphere. Equilibrium vertical distributions are calculated for nine gas concentrations, and the influence of atomic hydrogen in the mesosphere and the hydroxyl and perhydroxyl radicals in the stratosphere on the ozone concentration are shown to be significant factors. A nonequilibrium investigation is also made in which the variations of the gas concentrations are calculated as a function of the time of day. In particular, the results illustrate the variations of the gas concentrations at night and indicate that the altitude range 70 to 80 km appears to be very active photochemically at this time. The rate of formation of hydroxyl is analyzed to obtain an estimate of the diurnal variation of the hydroxyl airglow emission, as well as the vertical distribution of this emission. The theoretical results are shown to agree satisfactorily with observation, and it is concluded that the hydrogen-ozone reaction can adequately account for most of the observed features of the hydroxyl emission. Finally, the need to incorporate some form of molecular and eddy diffusion into the model is clearly indicated by the results.