The Contribution of Reaction HO2+0 → OH+O2 to OH Nightglow

Abstract

AbstractThe photochemical model for the OH Meinel bands nightglow emission is discussed. Both the expression for the number densities of OH(v ≤ 9) and the expression for the OH vibrational bands nightglow emission rates are derived from the photochemical model. The impact of chemical reaction, HO2+O → OH(v ≤ 6)+O2, on the number densities of OH(v ≤ 6) and on the OH(v'—v'')(v' ≤ 6) (v' represents the higher vibrational levels and v'' represents the lower vibrational levels) vibrational bands emission are studied detailedly. The results indicate that the contribution of the reaction to the number densities increases with decreasing v and the contribution to the OH(v'—v'') bands emission increases with decreasing v'. The calculations for vernal equinox, local midnight at (0°E, 45°N) show that the reaction makes the peak density at level v = 1 and the peak emission rate of the OH(1—0) vibrational band increase by about 33%, the peak density at level v = 6 and the peak emission rates of the OH(6—v'') vibrational bands increase by about 7%, the OH(1—0) band intensity increase by about 30%, and the OH(6—v'') bands intensities increase by about 11%. Furthermore, the reaction can make the widths of the altitude profiles of both the number densities and the vibrational bands emission rates increase, and the peak altitudes of these profiles lower by about 1 km. The contribution of the reaction is sensitive to the atomic oxygen density and temperature. It increases almost linearly with decreasing atomic oxygen density, and with increasing temperature. And it is the strongest at the summer solstice and the weakest at the winter solstice.