The Effect of Solar Activity on Total Electron Content (TEC) in Low-Latitude Regions: A Case Study of African Stations

Abstract

The vertical Total Electron Content (TEC) derived from Global Positioning System (GPS) observations for six African stations—Mbarara in western Uganda (30°S, 73°E), Malinda in central Mozambique (40°S, 19.41°E), La Misere in Seychelles (5°S, 48°E), Windhoek in Namibia (17°S, 09°E), Lusaka in Zambia (28°S, 31°E), and Hartebeest Hoek in South Africa (27°S, 04°E)—was used to study the effects of solar activity on TEC for ten solar quiet days in each month during the period 2010–2012. The seasonal effects of solar activity were analysed by grouping each month into four seasons: March Equinox, September Equinox, June Solstice, and December Solstice. The results show that equinoctial TEC values are higher than the solstice values for stations in the Southern Hemisphere. During the equinoctial months, the Sun is directly overhead in the equatorial region, resulting in higher ionization over these regions. Notable differences were observed in the dependence of TEC on F10.7 solar flux, varying with local time and latitude. In the early morning hours, TEC shows a notable divergence from F10.7, with a root mean square error of r (0.007). In contrast, from noon to the early afternoon, TEC aligns closely with F10.7, demonstrating a strong correlation of r (0.650), especially at lower latitudes.