Features of the Ionospheric Total Electronic Content Response to the Annular Solar Eclipse of June 21, 2020

The features of the annular solar eclipse of June 21, 2020, in variations of the ionospheric total electron content (TEC) were analyzed using GPS observations of the IGS network of China. It is noted that the ionospheric effects of annular eclipses have been much less studied than the effects of total or partial solar eclipses. Based on the analysis of diurnal TEC variations for the selected GPS stations, it was found that the effect of this eclipse had the form of a TEC depression with a minimum close to the maximum phase of the eclipse at the observation station. The eclipse effect was found to be more clear in TEC variations along individual satellites passes, which had the form of a trough-like depression. It is shown that the major component in the magnitude decrease and delay of the TEC minimum relative to the maximum eclipse phase is the magnitude of the eclipse for a particular station. This follows from the high correlation between these parameters and the magnitude of the eclipse. The delay varies from several minutes to tens of minutes, depending on the magnitude of the eclipse. The maximum value of the TEC decrease reached ~4–6 TECU. To analyze the spatiotemporal behavior of the TEC, the IONEX files with a 15-min resolution were used. It was found that the maximum TEC depression was consistent with the trajectory and position of the eclipse shadow on the Earth’s surface.