In Situ Measurements of OH and H02 in the Upper Troposphere and Stratosphere

Abstract

Recent aircraft and balloon borne measurements of OH and H02 are reviewed. The authors demonstrate the ability of the laser-induced fluorescence technique to provide accurate, high signal to noise ratio measurements of OH throughout the upper troposphere and stratosphere. HO2 is measured as OH after gas phase chemical titration with nitric oxide. The addition of the HOx measurement capability to the suite of instruments aboard the NASA ER-2 aircraft has provided a wealth of new information about the processes that determine the concentration of ozone in the lower stratosphere. These simultaneous, in situ measurements provide a unique test of our understanding of the mechanisms that control the odd-hydrogen chemistry of the lower atmosphere.