Ionospheric time-delay over akure using global positioning system observations

Abstract

Ionospheric time delay (VΔt) variability using Global Positioning System (GPS) data over Akure (7.15°N, 5.12°E), Nigeria, has been studied. The observed variability of VΔt in comparison to older results of vertical total electron content (TEC) across similar regions has shown equivalent signatures. Higher monthly mean values of VΔt (MVΔt) were observed during daytime as compared to nighttime (pre- and post- midnight) hours in all months. The highest MVΔt observed in September during daytime hours range between ∼6 and ∼21 ns (∼1.80 and ∼6.30 m) and at post-midnight, they are in the range of ∼1 to ∼6 ns (∼0.3 to ∼1.80 m). The possible mechanisms responsible for this variability were discussed. Seasonal VΔt were investigated as well.