Chemistry of vibrationally excited ozone in the upper atmosphere

Recent atmospheric and laboratory experiments have shown that significant nonthermal vibrational excitation of O 3 can occur near the mesopause. These results can be interpreted in terms of a steady state model in which O 3 (υ) is formed by radiative and chemical excitation and is destroyed by radiative and collisional deactivation. The only atmospheric chemical source of O 3 (υ) which can be clearly identified is the three‐body recombination of O with O 2 . Little is known about the detailed, level‐dependent kinetics of O 3 (υ), and several key assumptions are required for kinetic interpretation of the data. Predicted vibrational distributions, infrared band radiances, and diurnal effects are compared to in situ data in various assumed limits, and critical processes are discussed. Possible auroral sources of O 3 (υ) are also examined.