THE EFFECT OF SMALL-SCALE INHOMOGENEITIES ON OZONE DEPLETION IN THE ARCTIC

THE chemical processes involved in the depletion of polar stratospheri c ozone are now fairly well understood(1,2). But the effect of small-s cale stirring and mixing of the chemical species involved can be misre presented in three dimensional chemical-transport models because of th eir coarse resolution, Because of the nonlinearities in the chemical r ate laws, especially those involving chlorine in the main catalytic cy cle, these effects can be important-particularly in the Arctic, where the polar vortex is less uniform and less isolated from surrounding ai r than in the Antarctic, Here we use a very-high-resolution model with simplified ozone-depletion chemistry to show that the depletion is se nsitive to small-scale inhomogeneities in the distribution of reactant species, Under the conditions of the winter of 1994-95 the effect is large enough to account for the observed discrepancies of about 40% be tween modelled and observed ozone depletion in the Arctic environment( 3-5).