Study of the (4–1) and (5–2) Hydroxyl Bands in the Night Airglow

Abstract

A 1 year study of the (4–1) and (5–2) hydroxyl bands in the night airglow near 1 μ has revealed a non-uniform rotational temperature across the P branch of each band. The temperature increases with K′ value. There is a pronounced seasonal variation of temperature showing a summer minimum and winter maximum. The average measured brightness for the (4–1) band is 4.6 kR (winter) and 3.5 kR (summer), and for the (5–2) band is 5.8 kR (winter) and 4.3 kR (summer). It is shown that the time-averaged total band intensity fluctuations during a single night are quite large, sometimes a factor of 2, and are not definitely correlated with the rotational temperature during the same period.