Seasonal Variability of Ionospheric Scintillation over Lautech, Ogbomoso, Nigeria.

Abstract

This study investigates the seasonal and diurnal variability of ionospheric scintillation over Ladoke 
Akintola University of Technology (Lautech), Ogbomoso, Nigeria (8.17054400°N, 4.26892783°E, 403.411 
m), located within the low-latitude region of the Equatorial Ionization Anomaly (EIA). The analysis was 
based on high-rate (4 Hz) dual-frequency Global Positioning System (GPS) data recorded at the Lautech 
GNSS Laboratory (LGL) between 2024 and 2025, corresponding to the peak phase of Solar Cycle 25. 
Amplitude scintillation indices (S4) were derived from C/N₀ observations of GPS L1 signals using a 
customized MATLAB framework and Tec-suite software. Data were grouped into dry and rainy seasons to 
evaluate the spatial distribution, elevation dependence, and temporal occurrence of moderate (S4 ≥ 0.4) 
and strong (S4 ≥ 0.6) scintillation events. Results indicate that scintillation occurrence is strongly 
influenced by season, local time, and satellite elevation. The equinox months and their surrounding months 
experienced the highest activity. Rainy-season months showed more intense and frequent scintillation than 
dry-season months. A rare and significant finding was the detection of strong midday scintillation on August 
2 and 3, 2024, outside the typical post-sunset hours. These events happened at the same time as the accuracy 
of Precise Point Positioning (PPP) dropped, reaching 5 × 11 × 34 mm and 4 × 8 × 31 mm in latitude, 
longitude, and altitude, respectively. The study confirms that Nigeria’s equatorial region is among the most 
scintillation-active globally and that amplitude fluctuations directly influence Global Navigation Satellite 
Systems (GNSS) positioning performance. It provides the first documented evidence of concentrated strong 
midday scintillation in the Nigerian sector, establishes a quantitative link between S4 intensity and PPP 
accuracy, and delivers a locally validated GPS 4 Hz logged dataset in Nigeria, West Africa. These results 
offer valuable support for GNSS performance assessments, ionospheric modeling, and the development of 
regional mitigation strategies for low-latitude positioning applications.