The multi-year and global data base of ionospheric measurements from the CHAMP satellite contains an enormous potential to investigate the climatological behaviour of the electron temperature at an altitude of ~400 km. This height range has been sparsely covered by observations so far. In our paper we focus on the equatorial and low-latitude ionosphere, and we have investigated characteristic features such as the morning overshoot and the post sunset temperature anomaly showing similar features as the ionization anomaly. The electron temperatures at all local times show a positive correlation with the solar flux level, except for the morning overshoot where the dependence on the proxy F10.7 is very low. Instead, a distinct seasonal variation has been found in the morning hours, which hints to a dependence on solar zenith angle. Together with the electron density readings the data base enables to verify the Ne/Te (anti-) correlation for different solar flux levels at low latitudes.

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Stolle, C.; Liu, H.; Förster, M.; Truhlik, V.; Lühr, H. (2010): Ionospheric electron temperature from CHAMP observations. 38th COSPAR Scientific Assembly (Bremen 2010).