Source regions of irregularities causing GNSS radio scintillation: An investigation using EISCAT

Scintillation causing irregularities can occur in the E region or the F region ionosphere or even in both. This is due to the stochastic nature of the ionosphere that varies with the time of day, latitudes, seasons, solar and geomagnetic effects, etc. The relative importance of the different regions in hosting irregularities that can cause scintillation at GNSS frequencies in the dayside high latitude ionosphere is yet to be established. This study makes use of the 32-m European Incoherent SCATer (EISCAT) radar on Svalbard (ESR) to identify the ionospheric signatures during scintillation events. In particular, it takes advantage of the fast-scanning capability of ESR allowing it to image large areas of the ionosphere. This allows to capture ionospheric phenomena over a wide range of geographic latitudes in a short span of time. The scintillation measurements are obtained from the receiver installed at the nearby Kjell Henriksen Observatory (KHO) which can track signals from multiple GNSS constellations simultaneously. By combining the radar observations with scintillation measurements, the source regions responsible for GNSS scintillation at the dayside auroral/cusp regions are identified and characterized. The results are discussed in the context of nighttime statistics when patches and auroral dynamics are responsible for strong scintillation in GNSS signals. The results shown help better understand the impact of ionospheric irregularities on radio wave propagation in the high latitude ionosphere. Furthermore, the capability of extending the analysis to the upcoming EISCAT 3D using a simultaneous multi-beam multi-direction pattern is emphasized.