OZONE PRODUCTION AND LOSS RATE MEASUREMENTS IN THE MIDDLE STRATOSPHERE

We present the first simultaneous measurements of HOx, NOx, and Cl-x r adicals in the middle stratosphere obtained during a balloon flight at 34 degrees N in September 1989, along with calculations from a photoc hemical model, to show that NO, catalytic cycles dominate loss of ozon e (O-3) for altitudes between 24 and 38 km; the observed abundance of ClO is lower than that expected for altitudes above 30 km on the basis of models using recommended rates and cross sections, reducing the re lative importance of the Cl-x catalytic cycles for loss of O-3; and re moval rates of O-3 derived from observed concentrations of rate limiti ng HOx, NOx, and Cl-x radicals balance computed production rates for a ltitudes between 32 and 38 km, a region where ozone is expected to be regulated primarily by photochemical processes.