Arctic ozone loss due to denitrification

Measurements from the winter of 1994-95 indicating removal of total reactiv e nitrogen from the Arctic stratosphere by particle sedimentation were used to constrain a microphysical model. The model suggests that denitrificatio n is caused predominantly by nitric acid trihydrate particles in small numb er densities. The denitrification is shown to increase Arctic ozone Loss su bstantially. Sensitivity studies indicate that the Arctic stratosphere is c urrently at a threshold of denitrification. This implies that future strato spheric cooling, induced by an increase in the anthropogenic carbon dioxide burden, is likely to enhance denitrification and to delay until late in th e next century the return of Arctic stratospheric ozone to preindustrial va lues.