Nightglow Measurements of 630.0 nm Line from Kolhapur, India and Their Association with TEC Enhancements

Abstract

Nightglow measurements of 630.0 nm emission line by high resolution tilting photometer have been compared with simultaneous Faraday rotation measurements of the ionosphere's total electron content (TEC) from ETS-II satellite (-130°E) at a low latitude station, KOLHAPUR (Geog. lat. 16.8°N, long. 74.2°E, dip lat. 10.6°N) in India. The preliminary observational data are presented and discussed for seven nights during March, 1989 and April, 1990. The comparative study shows that in general the airglow enhancements are associated with the night time enhancement in TEC. The airglow enhancement due to downward motion of the F layer during pre-dawn hours does not correlate with TEC fluctuations. Further, the time rate of change of content has been used to obtain rough estimate of the nightglow intensity level at the station. On comparisons 630 nm emission intensities computed from TEC values and those predicted by MSIS-86 (Hedin, 1987) and FAIM (Anderson et al., 1989) models show an accepted level of agreement. Results focus the coupling between airglow producing irregularities and TEC at low latitude ionosphere.