Seasonal and Diurnal Variations of Ionospheric TEC across Latitudes: An IRI-2016 Model Study for Solar Minimum Conditions

Abstract

IRI-2016 simulated results are used to examine the daily and seasonal variations of Total Electron Content (TEC) in three different latitudinal belts including Berlin, Germany (52.471°N, 13.384°E) in the Northern Mid-Latitudes; Gabon (0.458°N, 4.12°E) in the Equatorial latitudes; and Pretoria, South Africa (-25.74°S, 28.22°E) in the Southern Mid-Latitudes. Predicted results from IRI-2016 for 2020, a solar minimum year when there was a transition from Solar Cycle 24 to 25, depict latitudinal dependence of the variations. Results from IRI-2016 reveal the presence of the Equatorial Ionization Anomaly (EIA) phenomenon in the equatorial belt (Gabon) with high TEC magnitude. In addition, IRI shows TEC maxima around post-noon time and higher TEC magnitude on equinoxes than on solstices. Moreover, enhanced night-time TEC in the Southern Hemisphere (Pretoria) is noted during winter solstices. This paper presents the examination of the ability of IRI-2016 in modelling climatological ionospheric phenomena during solar minima.