A simple calculation of ozone depletion by chlorofluoromethanes using a two-dimensional model

Abstract

THE possible perturbation of the total amount of ozone in the atmosphere due to man's activities has been the subject of much recent research. The vast majority of perturbation calculations have been performed using one-dimensional models in which variations in the vertical alone are considered. I describe here some simple calculations of the effects of chlorofluoromethanes on the ozone layer using a two-dimensional (latitude and height), time-dependent numerical model in which the mean circulation is computed at each time step. In our two-dimensional treatment the eddy transports of heat and matter are calculated using two-dimensional eddy diffusion coefficients, based on atmospheric statistics, and the eddy momentum fluxes are average monthly values for 1973 deduced from the Nimbus V Selective Chopper Radiometer measurements. The approach has proved successful in modelling many features of the unperturbed atmosphere and, in particular, of the behaviour of ozone in the stratosphere¹.