Assessing the performance of IRI-PLAS-MAP in the frame of hmF2 COSMIC observations over the African sector during the ascending phase of solar cycle 25

Continuous evaluation of ionospheric models is essential for enhancing their accuracy, thereby improving the capability to exhibit different features of the ionosphere. The present study utilizes the intensive and quiet time electron density peak height (hmF2) retrieved by the COSMIC-2 satellite during the first five years of solar cycle 25 (2020–2024) over the African sector (35°S:35°N latitudes, −20°W:55°E longitudes) in order to investigate the performance of the hmF2 maps provided by the International Reference Ionosphere extended to the Plasmasphere (IRI-PLAS-MAP). The African sector was selected due to the lack of ionosonde ground stations, which are the basis of the IRI-PLAS model. The results have shown that both the observed (COSMIC-2) and modeled (IRI-PLAS-MAP) data are consistent near solar minimum, where smoothed monthly values of the solar flux (10.7F = 70 sfu) were recorded during mid-2020. However, the differences between the observed and modeled datasets become increasingly divergent as we approach higher levels of solar activity, with smoothed monthly values of the solar flux (10.7F = 175 sfu) recorded during mid-2024. Moreover, the modelled data was found to underestimate the observed data by a percentage error up to 30 % during 2024. The regression analysis indicates that the degree of estimation decreases as solar maximum approaches, and the R²-values reflect this trend. Furthermore, the small p-values indicate that the discrepancy between the model and the observed data is statistically significant. Accordingly, this study recommends further refinement of the hmF2 maps derived from IRI-PLAS estimates over the African sector, particularly during periods of high solar activity and quiet geomagnetic conditions.