Characteristics of the midlatitude maximum in the O I 5577 Å airglow emission rate

Abstract

An analysis of O I 5577 Å airglow limbs observed on the night side of the earth by a scanning photometer on board the ISIS 2 satellite has provided sufficient data to establish the existence of a prominent midlatitude maximum in the airglow emission rate. The maximum occurs near 40° latitude in the winter and near 30° in the summer, with the winter hemisphere maximum a factor of 1.6 larger than the summer hemisphere maximum. The emission rate varies by a factor of about 4 during the year with the maximum occurring several weeks after the autumn equinox. It is suggested that these spatial and temporal variations are due to the distribution of atomic oxygen which, in turn, is influenced by large scale dynamical processes in the lower thermosphere.