Diurnal, seasonal and latitudinal variations of electron temperature measured by the SROSS C2 satellite at 500 km altitude and comparison with the IRI

P. K. Bhuyan (1) , M. Chamua (2) , P. Subrahmanyam (2) , S. C. Garg (2)

1 Department of Physics
2 Radio and Atmospheric Sciences Division

The diurnal, seasonal and latitudinal variations of electron temperature T_e, measured by the SROSS C2 satellite at equatorial and the low-latitudes during the low solar activity period of 1995?1997 are investigated. The average height of the satellite was ~ 500 km and it covered the latitude belt of ?31° to 34° and the longitude range of 40°?100°. T_e varies between 700?800 K during night-time (20:00?04:00 LT), rises sharply during sunrise (04:00?06:00 LT) to reach a level of ~ 3500 K within a couple of hours and then falls between 07:00?10:00 LT to a daytime average value of ~ 1600 K. A secondary maximum is observed around 16:00?18:00 LT in summer. Latitudinal gradients in T_e have been observed during the morning enhancement and daytime hours. Comparison of measured and International Reference Ionosphere (IRI) predicted electron temperature reveals that the IRI predicts nighttime T_e well within ~ 100 K of observation, but at other local times, the predicted T_e is less than that measured in all seasons.

Domaines: Océan, Atmosphère; Sciences de la Terre

P. K. Bhuyan, M. Chamua, P. Subrahmanyam, S. C. Garg. Diurnal, seasonal and latitudinal variations of electron temperature measured by the SROSS C2 satellite at 500 km altitude and comparison with the IRI. Annales Geophysicae, 2002, 20 (6), pp.807-815. ⟨hal-00317034⟩