ИСТИНА

With the development of GNSS systems, the coherent multifrequency L band transmissions are now available from a number of geostationary satellites. These signals can be used for ionospheric TEC estimations in the same way as widely used GPS/GLONASS signals, taking the advantage of almost motionless ionospheric pierce points [1]. Among these geostationary satellites, Chinese BDS-GEO are of the peculiar interest, providing the best noise pattern in TEC estimations, which corresponds to those of GPS/GLONASS systems [2]. In this work we discuss the capabilities of BDS-GEO data for studying ionospheric variability driven by space weather and meteorological sources at different time scales. Analyzing data from a number of IGS receivers we present seasonal variations of geostationary TEC in near equatorial ionosphere and its relation to Solar activity, as well as day-to-day TEC variability driven by Solar flares, geomagnetic storms, SSWs and typhoon activity. We also discuss seasonal and diurnal variations of ROTI index constructed from geostationary TEC estimations and its relation to the EPB occurrence. Our results show large potential of geostationary TEC estimations with BDS-GEO signals for continuous monitoring of low-latitude and equatorial ionosphere. [1] Kunitsyn V.E., Kurbatov G.A., Yasyukevich Yu.V. and Padokhin A.M. Investigation of SBAS L1/L5 signals and their application to the ionospheric TEC studies. IEEE Geoscience and Remote Sensing Letters (2015) 12, №3, p. 547-551. [2] Kunitsyn V.E., Padokhin A.M., Kurbatov G.A., Yasyukevich Y.V., Morozov Y.V. Ionospheric TEC estimation with the signals of various geostationary navigational satellites. GPS Solutions (2016), 20 № 4, p. 877-884.