OZONE VARIATIONS IN THE SCANDINAVIAN SECTOR OF THE ARCTIC DURING THE AASE CAMPAIGN AND 1989

The Airborne Arctic Stratospheric Expedition (AASE) carried out measur ements from January 3 to February 15, 1989. Enhanced levels of chlorin e compounds were found in the Arctic stratosphere, and on two single f lights ozone decrease of 17% were measured, interpreted as essential f eatures of the Arctic stratosphere, caused by a combined effect of enh anced amounts of chlorine compounds and presence of polar stratospheri c clouds. Related model calculations also indicate extended ozone depl etion maximizing in late March 1989 and amount to 5-8% in column at 70 -degrees-N. Ground-based ozone measurements, however, show that the mo st characteristic features during this period are temporal variations and a strong enhancement of ozone, probably due to an extended stratos pheric warming. From these measurements it is hard to see any effect o f an eventual enhanced burden of stratospheric chlorine, which might s how up as an extended and long-lasting decrease of stratospheric ozone , but its eventual existence is masked by the temporal variations.