Solar eclipses provide a distinctive opportunity to study the interactions between solar radiation and the Earth’s ionosphere. This study focuses on the ionospheric response, particularly Total Electron Content (TEC) variations, during the annular solar eclipse on December 26, 2019.
TEC from four GNSS stations, YIBL (22.186 °N, 56.112 °E), IISC (13.021 °N, 77.570 °E), HYDE (17.417 °N, 78.551 °E), and GUUG (13.433 °N, 144.803 °E) was analyzed using dual-frequency GPS receiver data. During the solar eclipse, TEC decreased at all four stations; the maximum
reductions were observed at IISC (33.12%), HYDE (32.01%), GUUG (29.73%), and YIBL (26.33%). To observe the influence of the geomagnetic storm on TEC during the eclipse, the study analyses the Dst index, Kp index, interplanetary magnetic field (Bz), and electric field (Ey). The study
showed that storm activity did not influence TEC during the solar eclipse and that the observed change in TEC was due solely to the eclipse on December 26, 2019. The study compares IRI-2020 model TEC data and observed TEC data during storm days. The results also showed a good correlation between them at IISC, HYDE, and GUUG, whereas there was a moderate correlation at YIBL. The findings provide essential understanding of ionospheric behaviour during eclipses and elucidate the need to improve ionospheric models with real events to improve space
weather forecasting and reliability of satellite communications.