Relative intensities of the O2+ 1NG and N2 1PG band systems in normal and type-B aurora

Abstract

A wavelength scanning spectrometer has been used to study the intensities of selected O2+ 1NG and N2 1PG bands in the visible spectra of normal and type-B aurora. Peak differential brightnesses are considered. It has been found that I (O2+ 1NG)/I(N2 1PG) is constant to within 70% in both normal and type-B aurora of intensities IBC I through IBC III. The relevance of these observations, in view of previously published results on the subject of type-B aurora, is discussed.