Near Real-Time Global Plasma Irregularity Monitoring by FORMOSAT-7/COSMIC-2

Abstract:

This study presents initial results of the ionospheric scintillation in the F layer using the S4 index from the radio occultation experiment (RO-S4) of the FORMOSAT-7/COSMIC-2 (F7/C2). With sufficiently dense RO-S4 observations at low latitudes, it is possible to construct hourly global scintillation maps to monitor equatorial plasma bubbles (EPBs). The F7/C2 RO-S4 during August 2019 to April 2020 show that scintillations are mostly distributed around American and the Atlantic Ocean sectors. The RO-S4 near Jicamarca are compared with range-time-intensity (RTI) images of the 50 MHz radar, showing that RO-S4 intensity and the occurrence of S4 equal to 0.125-0.5 are collocated with the bottomside of the spread-F patterns. The occurrence of RO-S4 increases at the upward phase of oscillations is consistent with the theory of the large scale wave seeding of the EPBs. The locations and occurrences of the RO-S4 greater than 0.5 also agree with the airglows taken from the NASA GOLD mission. Climatology analyses show that monthly occurrences of RO-S4 > 0.5 well agrees with the monthly EPB occurrences detected by the GOLD 135.6nm image, and show similar longitudinal distribution pattern with the DMSP and C/NOFS in-situ measurements, suggesting the designated RO-S4 intensities can be utilized to identify the EPBs of specific scales.