GLOBAL IMPACT OF THE ANTARCTIC OZONE HOLE - DYNAMIC DILUTION WITH A 3-DIMENSIONAL CHEMICAL-TRANSPORT MODEL

In separate numerical experiments a hypothetical Antarctic ozone "hole' is induced on September 1 and on October 1; the CTM is integrated for 1 year with a linearized model that assumes standard photochemistry, not including the heterogeneous reactions and unusual chemistry associated with formation of the ozone hole. The initial depletion, assumed to be 90% of the O3 poleward of 70°S between 22 and 200 mbar, amounts to about 5% of the total O3 in the southern hemisphere. As the vortex breaks down and the ozone hole is dispersed, significant depletions to column ozone, of order 10 Dobson units (3%) occur as far north as 40°S during austral summer. One year later, only 30% of the original depletion remains, mostly below 100 mbar and poleward of 30°S. The October 1 initialization is continued for a second year, the ozone hole being reinduced 1 year later with the same parameterization. -from Authors