An upper tropospheric high pressure system resulting in large scale ascent even in the stratosphere, is investigated by means of simulations using the coupled dynamic-chemical general circulation model ECHAM3/CHEM. 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 stratospheric clouds caused by adiabatic cooling leads to a chlorine activation at the location of the ozone mini-hole. The resulting chemical ozone depletion occurs downstream of the ozone mini-hole, due to the stratospheric calculation.¿ 1997 American Geophysical Union