Electron and ion temperature and electron density at ±10° magnetic latitudes from SROSS C2 measurements over India and comparison with the IRI Original Research Article

Diurnal and seasonal variation of electron and ion temperature and electron density at ∼500 km altitude measured by the Indian SROSS C2 satellite during 1995–96 are investigated. Two representative magnetic latitudes ±10° are considered. Electron temperature (Te) varies between 800°K and 900°K during nighttime, rises sharply at sunrise to 3000°K and then falls to a daytime average of 1500°K. A secondary enhancement of Te within 1500–1800 LT was observed in summer and equinox. Ion temperature (Ti) was found to be less than Te at both the locations and in all seasons. Electron density (Ne) shows a minimum before sunrise and a maximum in the afternoon. Seasonal as well as spatial differences in the diurnal behaviour were observed in case of all three parameters. Comparison of density and temperature measured by SROSS C2 with the IRI reveals that IRI underestimates Te during daytime and overestimates Ne at about all local times. Predicted and observed Ti also differ.