Time dependent studies of the aurora—II. Spectroscopic morphology

The temporal morphology of auroral spectral emission features is investigated. For a given energy distribution of bombarding electrons but a time varying flux magnitude, the emission rates of various auroral radiations exhibit a nonlinear time response due to the variety of reactions that contribute to excitation. Absolute intensities and intensity ratios of various spectroscopic features, therefore, can vary solely with atmospheric interaction effects, indicating the importance of considering the time history of a precipitation event when attempting to infer the characteristics of auroral electrons from optical measurements.