GLOBAL IMPACT OF THE ANTARCTIC OZONE HOLE - CHEMICAL-PROPAGATION

A model is presented for the chemical mixing of stratospheric air over spatial scales from tens of kilometers to meters. Photochemistry, molecular diffusion, and strain (the stretching of air parcels due to wind shear) are combined into a single one-dimensional model. The model is applied to the case in which chemically perturbed air parcels from the Antarctic stratosphere are transported to mid-latitudes and strained into thin ribbon-like filaments until they are diffusively mixed with the ambient stratosphere. We find that the parcels may be treated as evolving in chemical isolation until the final mixing. For this sensitivity study we consider four types of Antarctic air: a control case representing unprocessed polar air, heterogeneous processing by polar stratospheric clouds (PSCs) that has repartitioned the Clx and NOy families; processing that also includes denitrification and dehydration; and all processing plus 90% ozone depletion. -from Authors