title: Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere
abstract: The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.
authors.affiliation: P. O. Wennberg, T. F. Hanisco, E. J. Hintsa, E. J. Lanzendorf, J. G. Anderson, Department of Chemistry and Chemical Biology and Department of Earth and Planetary Sciences, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA. L. Ja.
authors.initials: PO
authors.lastname: Wennberg
authors.initials: TF
authors.lastname: Hanisco
authors.initials: L
authors.lastname: Jaegle
authors.initials: DJ
authors.lastname: Jacob
authors.initials: EJ
authors.lastname: Hintsa
authors.initials: EJ
authors.lastname: Lanzendorf
authors.initials: JG
authors.lastname: Anderson
authors.initials: R
authors.lastname: Gao
authors.initials: ER
authors.lastname: Keim
authors.initials: SG
authors.lastname: Donnelly
authors.initials: LAD
authors.lastname: Negro
authors.initials: DW
authors.lastname: Fahey
authors.initials: SA
authors.lastname: McKeen
authors.initials: RJ
authors.lastname: Salawitch
authors.initials: CR
authors.lastname: Webster
authors.initials: RD
authors.lastname: May
authors.initials: RL
authors.lastname: Herman
authors.initials: MH
authors.lastname: Proffitt
authors.initials: JJ
authors.lastname: Margitan
authors.initials: EL
authors.lastname: Atlas
authors.initials: SM
authors.lastname: Schauffler
authors.initials: F
authors.lastname: Flocke
authors.initials: CT
authors.lastname: McElroy
authors.initials: TP
authors.lastname: Bui