On the interaction between gravity waves and the OH Meinel (6‐2) and the O2 atmospheric (0‐1) bands in the polar night airglow

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Abstract
The effect of gravity waves on the OH (6–2) and O2 (0–1) airglow emissions was examined using spectroscopic airglow data from Longyearbyen, Svalbard (78°N), and Fairbanks, Alaska (64°N). The analysis was done by fitting a synthetic spectrum to the data to infer the rotational temperature as well as the band intensity of each of the emissions. Quasi‐periodic fluctuations in the band intensity and rotational temperature are assumed to be a result of modifications of a stable airglow layer by gravity waves. The relationship of the fluctuations in band intensity to rotational temperature may be expressed in terms of the parameters η, which is defined as the ratio of the amplitudes of the fluctuations in intensity and temperature, and θ, which is the phase angle between the fluctuations in intensity and temperature. These parameters were observed to vary with wave period for both the OH and O2 emissions. The variations in η(OH) and θ(OH) agreed fairly well with the most recent models for waves with periods of about 1 hour or longer. None of the models agree with the observed values of η(OH) and θ(OH) for short‐period waves. For the O2 emissions, the observed values of η(O2) range between 1 and 8 and do not agree with the model calculations, but θ(O2) is generally 180° which is expected from first‐order linear gravity wave theory.