Aircraft Borne Measurements of Infrared Enhancements during ICECAP 1975 and 1976,

Abstract

Abstract : Significant infrared emission enhancements in the 2.75-3.04 micrometer region have been measured from the NKC-135A aircraft while viewing an aurorally excited atmosphere with a radiometer. The measured enhancements occurred while viewing all types of auroral forms, and they became significant with respect to the night sky background emissions whenever the N2(+) emissions at 3914A exceeded about 20 kiloRayleighs. Within the angular resolution capabilities of the instrumentation, the measured 2.8 micrometers enhancements appeared to co-vary spatially and temporally with enhancements in the ionization-prompt fluorescence of the N2(+). The enhancements did not correlate with emissions of the (5,3) band of the hydroxyl (OH) DeltaV=2 sequence at 1.7 micrometers. It appears that the most probable source creating the enhancements is the first overtone of nitric oxide (NO). Using the measured 2.8 micrometers and 3914A data and a synthetic NO model, the percentage of the total auroral electron energy which is radiated as first overtone NO photons was calculated for seven enhancement periods. The calculated percentage, photo-energy efficiencies, ranged from .4% to 1.0%.