Abstract. 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 nighttime (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.

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