The Venus OH Nightglow Distribution

The study shows that the OH emission is highly variable, ranging from less than 20 kR to about 2 MR. The peak brightness appears to decrease away from the antisolar point even if the variability at a given location is very strong. By contrast, although the OH peak altitude also appears to be variable, it shows no dependence with the location on the nightside of Venus. Some correlation between simultaneous observations of the intensity of the OH and the O2(a1Δ) emissions has also been detected, presumably because atomic oxygen is a common precursor to the formation of O2(a1Δ) and O3, whose reaction with H produces excited OH. Anyway, it is important to keep in mind that horizontal transport plays an important role in the redistribution of photochemically produced species such as O, O3 and minor long-lived species and possibly explains some of the variability of the OH emission and its brightness relative to O2(a1 )