HETEROGENEOUS PSC OZONE LOSS DURING AN OZONE MINI-HOLE

An upper tropospheric high pressure system resulting in large scale ac cent even in the stratosphere, is investigated by means of simulations using the coupled dynamic-chemical general circulation model ECHAM3/C HEM. These simulations show two kinds of impact on stratospheric ozone . Dynamic redistribution caused by ascent leads to a rapid decrease of total ozone, i.e. an ozone mini-hole. The formation of polar stratosp heric clouds caused by adiabatic cooling leads to a chlorine activatio n at the location of the ozone mini-hole. The resulting chemical ozone depletion occurs downstream of the ozone mini-hole, due to the strato spheric circulation.