The effect of dynamical mixing in a simple model of the ozone hole

The role of the horizontal dynamical mixing on the ozone destruction by chlorine in the polar stratosphere is investigated. We use a one- dimensional high-resolution model to represent the microstructure of chemical species distribution on which the effective reactivity depends. The chemical model is idealized by only considering two species, ozone and chlorine (assumed to be under the active form CIO). Ozone destruction is proportional to the square of chlorine content. We compare the effects of a chaotic type of mixing, represented as a Bernoulli map over the unit interval, with purely diffusive mixing, which is used in most parameterizations of turbulence. The comparison is done for various values of the chemical reactivity constant. Owing to the nonlinearity of the chemical reaction, reactivity decreases with mixing if the chemical constant is small, while it increases with mixing for large values of the chemical constant. In any situation, large discrepancies in the ozone destruction are observed between chaotic and diffusive mixing, indicating the need for a better representation of the mixing processes in studies of stratospheric chemistry.