Effect of dynamical‐photochemical coupling on oxygen airglow emission and implications for daytime ozone retrieved from 1.27 μm emission

Abstract

A one‐dimensional photochemical‐diffusive‐advective model is used to quantitatively investigate the effects of dynamical‐photochemical coupling on the O2(a1Δg) concentration and the derived O3 concentration based on the 1.27‐μm airglow emission in the upper mesosphere and lower thermosphere. We compare the fractional differences of O2(a1Δg) and O3 concentrations between those derived from the coupled model and from a photochemical steady state model that is often used for retrievals by airglow emissions. It is found that the fractional differences resulting from the use of a steady state model have a strong local time dependence when the chemical/radiative lifetime of O2(a1Δg) is comparable to that of diurnal variations and the transport timescale of tidal waves. In the upper mesosphere and lower thermosphere, especially near the mesopause region, the fractional difference may range from more than 100% in early morning immediately after sunrise to about 10% or less in the later afternoon.