Coordinated thermospheric day‐night airglow and ionospheric measurements from low latitudes—First results

The Dayglow photometer which monitors the O(¹D) 630.0 nm thermospheric airglow emission, has been converted into a day-night photometer and was operated from Waltair (17.7°N, 83.3°E dip. Lat. 10.09°N) during March 1998 as a part of the Indian Solar Terrestrial Energy Programme (ISTEP) campaign. The first results on the day-night airglow measurements together with ionosonde data from the same location are scrutinized in the present exercise. The base height of the F-layer (h'F) showed a strong negative correlation with dayglow intensity similar to nighttime conditions and a new empirical relation (Barbier type) linking the F-region electron densities and the h'F with the dayglow intensity has been worked out highlighting the importance of chemical processes in OI 630.0 nm dayglow and its variabilities.