Identification of potential precursors for the occurrence of Large-Scale Traveling Ionospheric Disturbances in a case study during September 2017

Abstract

Traveling Ionospheric Disturbances (TIDs) reflect changes in the ionospheric electron density which are caused by atmospheric gravity waves. These changes in the electron density impact the functionality of different applications such as precise navigation and high-frequency geolocation. The Horizon 2020 project TechTIDE establishes a warning system for the occurrence of TIDs with the motivation to mitigate their impact on communication and navigation applications. This requires the identification of appropriate indicators for the generation of TIDs and for this purpose we investigate potential precursors for the TID occurrence. This paper presents a case study of the double main phase geomagnetic storm, starting from the night of 7th September and lasting until the end of 8th September 2017. Detrended Total Electron Content (TEC) derived from Global Navigation Satellite System (GNSS) measurements from more than 880 ground stations in Europe was used to identify the occurrence of different types of large scale traveling ionospheric disturbances (LSTIDs) propagating over the European sector. In this case study, LSTIDs were observed more frequently and with higher amplitude during periods of enhanced auroral activity, as indicated by increased electrojet index (IE) from the International Monitor for Auroral Geomagnetic Effects (IMAGE). Our investigation suggests that Joule heating due to the dissipation of Pedersen currents is the main contributor to the excitation of the observed LSTIDs. We observe that the LSTIDs are excited predominantly after strong ionospheric perturbations at high-latitudes. Ionospheric parameters including TEC gradients, the Along Arc TEC Rate (AATR) index and the Rate Of change of TEC index (ROTI) have been analysed for their suitability to serve as a precursor for LSTID occurrence in mid-latitude Europe, aiming for near real-time indication and warning of LSTID activity. The results of the presented case study suggest that the AATR index and TEC gradients are promising candidates for near real-time indication and warning of the LSTIDs occurrence in mid-latitude Europe since they have a close relation to the source mechanisms of LSTIDs during periods of increased auroral activity.

Ionosonde Observations of Spread F and Spread Es at Low and Middle Latitudes during the Recovery Phase of the 7–9 September 2017 Geomagnetic Storm

“…The passage of LSTIDs in low and middle latitudes generates radio waves scattering, shown as spread F and spread Es in Figures 3-5. However, it should be noted that TIDs/AGWs during the recovery phase of the storm might mix multiple scales of TIDs/AGWs in low and middle latitudes, including the residual largescale TIDs generated in the main phase period [31,59,60], medium-scale and small-scale TIDs originated from the local lower atmosphere, especially at the ZHY station where gravity waves are abundant [61]. During the storm, atmosphere disturbances are violent and often accompanied by atmospheric convection.…”

Large‐Scale Traveling Ionospheric Disturbances Over the European Sector During the Geomagnetic Storm on March 23–24, 2023: Energy Deposition in the Source Regions and the Propagation Characteristics

“…To derive oscillational features of TIDs, high‐pass or band‐pass filtering of VTEC can be used. Previous studies used moving average (Borries et al., 2023; Ferreira et al., 2020; Zakharenkova et al., 2016), polynomial fits (Ding et al., 2007; Habarulema et al., 2015; Nykiel et al., 2017), or other estimations of background TEC or trends (Hernández‐Pajares et al., 2006). All these methods give similar results without any significant differences.…”

Hybrid Model for Time Series of Complex Structure with ARIMA Components

“…Ionospheric anomalies occur during extreme solar events (solar flares and particle ejections) and magnetic storms. They cause serious malfunctions in the operation of modern ground and space technical equipment [42]. An important parameter characterizing the state of the ionosphere is the critical frequency of the ionospheric F2-layer (foF2).…”