An analysis of global ionospheric disturbances and scintillations during the strong magnetic storm in September 2017

Abstract

Severe space weather events, e.g., solar flares and magnetic storm, can cause significant disturbances to the global ionosphere. The radio frequency signals, such as wireless communications and global satellite navigation system (GNSS) signals, often experience strong scintillations when traveling through the disturbed ionosphere layer. On 6 September 2017, the sun emitted the largest solar flare classified X9.3 since the 24th solar activity week. It triggered the geomagnetic storm and ionospheric storm on September 8, causing severe disturbances and scintillations of ionospheric. In this work, we take this event as the objective to investigate the characteristics of the ionosphere disturbance. First, the temporal and spatial distributions of ionospheric total electron content (TEC) are analyzed using the ground-based IGS data. The change of TEC is highly correlated with that of the geomagnetic indices and the magnetic storm has the greatest impact on low latitudes. Then, a five-point moving average method is adopted to extract the spatial fluctuations based on post-processed electron density and TEC data from COSMIC and GRACE missions. We find they show different disturbance characteristics in spatial distribution. In addition, the GNSS amplitude scintillation index S4 which is available from the COSMIC satellite mission is used to characterize ionospheric scintillation during this event. Weak scintillation occurred in most parts of the world on September 8 2017, while moderate scintillation is mainly concentrated around 120° W and 100° E. Our study can provide a basis for better evaluating the impact of ionosphere disturbance changes on satellite communication and navigation in space weather events.