Ozone destruction and production rates between spring and autumn in the Arctic stratosphere

Abstract

In situ measurements of radical and long-lived species were made in the lower Arctic stratosphere (18 to 20 km) between spring and early autumn in 1997. The measurements include O 3, ClO, OH, HO 2, NO, NO 2, N 2 O, CO, and overhead O 3. A photochemical box model constrained by these and other observations is used to compute the diurnally averaged destruction and production rates of O 3 in this region. The rates show a strong dependence on solar exposure and ambient O 3. Total destruction rates, which reach 19%/month in summer, reveal the predominant role of NO(x) and HO(x) catalytic cycles throughout the period. Production of O 3 is significant only in midsummer air parcels. A comparison of observed O 3 changes with destruction rates and transport effects indicates the predominant role of destruction in spring and an increased role of transport by early autumn.