The temperature dependence of airglow emissions from the upper mesosphere and lower thermosphere

An analysis of a long time-series of measurements of the airglow emissions, OH(9, 4) 775.0 nm, NaD 589 nm, OI 557.7 nm and O 2 (0, 1) 864.5 nm atmospheric band, shows that the nocturnal mean intensities of all these emissions are highly correlated with the nocturnal temperature means, as determined from the rotational structure of the OH(9, 4) emission. After removing seasonal and long-term variations, the closest correlation is observed between the OH (9, 4) emission intensity and the corresponding rotational temperature, followed by the NaD, and the OI 557.7 nm and O 2 A emissions. The regression coefficients, ( d I I ) ( d T T ) , where I is intensity and T is temperature, are between 8 and 9 for the NaD and oxygen emissions, and about 5.5 for the OH band. It is clear that these regression coefficients do not reflect the temperature dependences of the various reactions involved. It seems probable that the observed correlations are the result of correlated temperature and density changes in the upper atmosphere.