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.

Effect of Photochemical Models on Calculated Equilibria and Cooling Rates in the Stratosphere

“…Since these calculations were made, the rates for pure oxygen reactions have been questioned and alternative rates have been proposed. In addition it now seems that reactions involving nitrogen and hydrogen compounds may be significant in determining the ozone distribution in the stratosphere .1 3 (Hunt 1966, Leovy 1969a, Crutzen 1971) and such reactions should therefore be.included in the photochemical model. Most of the 'rates for reactions involving hydrogen compounds are not temperature dependent so there is a question as to the influence of these reactions on the coupling between ozone density and temperature.…”

“…PHOTOCHEMICAL MODEL As many as 80 different reactions have been considered for an atmosphere consisting of nitrogen, hydrogen, oxygen, and their compounds (Hunt 1966, Shimnazaki and.Lai-rd 1970, Crutzen 1971.…”

Two‐dimensional monthly average ozone balance from limb infrared monitor of the stratosphere and stratospheric and mesospheric sounder data

“…It became clear in the mid-1960's that the Chapman mechanism was not sufficient to balance the production of ozone due to the photolysis of molecular oxygen. Hunt [1966] added the HO,, catalytic loss of ozone in a onedimensional calculation that included measurements of H20 and 03. Crutzen [1970] noted that the NO,, family also provides a catalytic loss for ozone and included this loss in a one-dimensional calculation of the production and loss terms of ozone using measurements of H20, 03, and HNO 3 as well as some calculations of NO2.…”

Carbon dioxide density and 15.MU. band radiation in the mesosphere and lower thermosphere.

“…where [n]=number density of n-th component, Dn=effective molecular diffusion coefficient of n-th component, K=eddy diffusion coefficient, T=temperature, a: KAUFMAN, 1969b: BALDWIN et aly 1970c: REEVES et al, 1960d: BENSON and AXWORTHY, 1965e: FITZSIMON and BAIR, 1964 f: SCHIFF, 1969 g: KAUFMAN, 1964 h: HUNT, 19661: FONER and HUDSON, 1962j: CLARK and WAYNE, 1969k: CLARK et al, 1970 1: EVANS and LLIWELLYN, 1972 Unit of rate constant: three-body recombination (cros sec-) two-body recombination (cm3 sec') Photodissociation and photoionization (sec-i) [N]=total particle density, c=particle flux of species n, D=mutual molecular diffusion coefficient between n-th and m-th component, H n=scale height of n-th component, Have=average scale height.…”