On the Relationship between Low Latitude Scintillation Onset and Sunset Terminator over Africa

The solar terminator is a moving boundary between day-side and night-side regions on the Earth, which substantial source of perturbations in ionosphere. In vicinity terminator, essential parameters like S4 index measurements are widely analyzed order to monitor predict utilization scintillation well-accepted approach describe amplitude/intensity fluctuation received signal, predominantly caused by small-scale irregularities ionospheric plasma. We report longitudinal daily seasonal occurrence GNSS signal scintillations, using data derived from stations Bahir Dar, Ethiopia, Lomé, Togo Dakar, Senegal. observed climatology scintillations equatorial Africa adequately explained alignment local geomagnetic declination line. It should be pointed out that strongest most frequently during time when best aligned with At all three stations, comparison computational observational results indicated activity culminated around equinoxes years 2014, 2015 2016. Comparatively, western sector has intense, longest-lasting, highest rate equinoctial seasons years. For first time, we show variation peaks changes systematically west east at over Africa. A detailed analysis day–night azimuth heights including equation shows intensity maximum if coincides line field. Due remarkable change about 10° considered distance increases 46 days westward Dar Dakar station. observations agree quite well results, thus confirming Tsunoda’s theory.