N2(B3 Πg) and N+2(A2 Πu) vibrational distributions observed 2 in sprites

A pair of spectra taken simultaneously by two different ground-based instruments has been analyzed by our group. As with previous observations, the spectra are composed primarily of the N-2 first positive group (1PG) (B(3)Pi(g) - A(3)Sigma(u)(+)). In a previous study, we compared the N-2(B) vibrational distributions from the spectral analysis with those resulting from a time-dependent kinetic model of N-2 triplet excited state populations. Both spectra reflect emission between 50 and 60 km. The higher-attitude spectrum is primarily 1PG but also shows the presence of features which appear to be N-2(+) Meinel (A(2) Pi(u) - X(2)Sigma(g)(+)). The lower-attitude spectrum shows little or none of the apparent Meinel emission but has an N-2(B) vibrational distribution similar to ones observed in laboratory afterglows. In this paper we discuss the apparent presence of the Meinel emission and present the observed N-2(B) vibrational distributions. (C) 2003 Elsevier Science Ltd. All rights reserved.