Sprite spectra; N₂ 1 PG band identification

Imagery and spectra of high altitude luminous flashes, otherwise known as sprites, occurring in the stratosphere/mesosphere above electrically active cumulonimbus clouds were acquired on July 16, 1995 from an observation site near Ft. Collins, Colorado. The spectra, resolved from ∼4500–8000 Å included four spectral features in the 6000–7600 Å region which have been identified as N 2 1PG system with Δv=2,3, and 4 from the v=2,4,5,6 vibrational levels of the B³π g state. The spectra were lacking in other features such as the N 2 + Meinel or the N 2 + 1st neg system indicating that the electron energy causing the excitation is quite low.