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Abstract

Accurate and precise specification and characterization of the ionospheric electron density (Ne) irregularities are important to radio sky-wave communications and satellite navigation. In this scenario, multi-instruction and multi-station systems are proposed to be organized for ionospheric F-layer irregularity and scintillation observations in the low-latitude regions. We first indicate the existence of an equatorial plasma bubble (EPB) using the FS7/COSMIC2 GPS/GLONASS radio occultation (RO) observations. We verify the latitudinal extent of the tracked plasma bubble using the recorded ionograms from the Vertical Incidence Pulsed Ionospheric Radar (VIPIR) network located in the east-Asia area. We further discuss the spatial and temporal variabilities of two-dimensional vertical scintillation index VS4 maps based on the simultaneous GPS L1-band signal measurements from more than 130 ground-based receivers located in Taiwan. We also operate more than four high-sampling software-defined GPS&SBAS receivers in Taiwan and characterize the targeted plasma irregularities by carrying out spectrum analyses of the received signal. Furthermore, we suggest that a post sunset decrement on the virtual heights of fixed-frequency ionospheric echoes could be a good precursor for post sunset scintillation and equatorial spread-F events. Such features can be used for correlation analysis and comparisons with plasma drifts retrieved by the International Reference Ionosphere (IRI) model.