Abstract. In this paper, an empirical total electron content (TEC) model and trends in
the TEC over the African low-latitude region are presented.
GPS-derived TEC data from Malindi, Kenya (geographic coordinates
40.194∘ E, 2.996∘ S), and global ionospheric maps (GIMs)
were used. We employed an empirical orthogonal function (EOF) analysis method
together with least-squares regression to model the TEC. The EOF-based TEC
model was validated through comparisons with GIMs, the GPS-derived TEC and
the TEC derived from the International Reference Ionosphere 2016 (IRI-2016)
model for selected quiet and storm conditions. The single-station EOF-based
TEC model over Malindi satisfactorily reproduced the known diurnal,
semiannual and annual variations in the TEC. Comparison of the EOF-based TEC
model results with the TEC derived from the IRI-2016 model showed that the
EOF-based model predicted the TEC over Malindi with fewer errors than the
IRI-2016. For the selected storms, the EOF-based TEC model simulated the
storm time TEC response over Malindi better than the IRI-2016. In the case of
the regional model, the EOF-based TEC model was able to reproduce the TEC
characteristics in the equatorial ionization anomaly region. The EOF-based
TEC model was then used as a background for estimating TEC trends. A
latitudinal dependence in the trends was observed over the African
low-latitude region.
A study on the variability of ionospheric total electron content over the East African low-latitude region and storm time ionospheric variations
