Reactive nitrogen, ozone, and nitrate aerosols observed in the Arctic stratosphere in January 1990

Abstract

On January 18, Kiruna was located inside the polar vortex, while it was outside the vortex on January 31. The NOy mixing ratio inside the vortex was 5 ± 1 parts per billion by volume (ppbv) at the altitudes between 20 and 22 km. This value is considerably smaller than the value of about 13 ppbv that is expected from gas phase chemistry, indicating that a degree of denitrification had occurred by mid-January in 1990. On the other hand, the NOy mixing ratio outside the vortex in the same altitude region ranged between 6 and 13 ppbv, suggesting less denitrification outside the vortex. The cause of the denitrification is interpreted in terms of the very cold stratospheric temperature that prevailed from December 1989 to January 1990. -from Authors