OPTICAL SIGNATURES OF LIGHTNING-INDUCED HEATING OF THE D-REGION

Lightning-induced heating of the nighttime D region leads to the excitation of a number of lines of O, O2, N2, O2+ and N2+ at intensities of 10-10(9) Rayleighs (R) for vertical observations. For example, the 5577 angstrom emission from O has intensity approximately 60 R lasting for approximately 350 ms while the 1st and 2nd positive bands of N2 are at approximately 10(9) R but last only approximately 50mus.