On the estimation of scintillation severity using background F-region peak densities: description and example results using GOLD observations

Abstract

Amplitude scintillations in Global Navigation Satellite System (GNSS) signals are commonly observed at low latitudes and are frequently associated with equatorial plasma bubbles. The scintillation severity is enhanced around the equatorial ionization anomaly, being controlled, in great part, by the ionospheric F-region background density. This work proposes the use of collocated observations from space-based and distributed ground-based monitors to quantify the relationship between the background F-region peak electron density (NmF2) and scintillation severity. To test the proposed approach and its feasibility, NmF2 observations from the Global-scale Observations of the Limb and Disk (GOLD) instrument and L-band scintillation measurements made by a network of GNSS-based scintillation monitors were used. The observations were made at low latitudes in October 2022, during the ascending phase of solar cycle 25. Results show the influence of background NmF2 on scintillation severity. The results also quantify the control of the latitudinal distribution of maximum S 4 values [S 4 (max)] by the latitudinal variation of NmF2. An empirical relationship between NmF2 and S 4 (max) for a given local time was also derived for the time of GOLD observations. An application of the empirical relationship between NmF2 and maximum S 4 is illustrated with regional (Brazilian) maps of potential maximum scintillation severity using GOLD-like data. Encouraging results include showing that S 4 (max) can be estimated from independent observations for a distinct longitude sector, but similar solar flux and season. Future studies will address to what extent the relationship between NmF2 and S 4 (max) varies for different geophysical conditions.