Characteristics of Equatorial F-region Irregularities along the 90°E Meridian during High Solar Activity Phase

Abstract

This study investigated the characteristics of the Equatorial ionospheric F-region Irregularities (EFIs) along the 90°E meridian using the phase fluctuations of Global Navigational Satellite System (GNSS) signals during the maximum phase of solar activity in the solar cycle 24. Results indicate that the occurrence of EFIs is related to the local time, season and magnetic latitude. The EFIs are usually observed during the post-sunset hours and are more pronounced before midnight. In the equinox seasons, EFIs are more common and intense around the magnetic equator and low latitude regions. The disappearance time of EFIs is late during the spring equinox season than the autumn equinox. The occurrence probability of severe EFIs is high in the equinox seasons than in the solstice seasons, especially in spring equinox. Moderate EFIs are observed more in the spring equinox season over the pole-ward edge of the Equatorial Ionization Anomaly (EIA) region in both the hemispheres. This study helps in understanding the spatio-temporal characteristics of EFIs and thereby mitigating the scintillation effects in highly precise and dynamic applications of satellite-based navigation systems over the equatorial and low latitude Indian sector.