Multi-instrument detection in Europe of ionospheric disturbances caused by the 15 January 2022 eruption of the Hunga volcano

Abstract

The 15 January 2022 eruption of the Hunga volcano provides a unique opportunity to study the reaction of the ionosphere to large explosive events. In particular, this event allows us to study the global propagation of travelling ionospheric disturbances using various instruments. We focus on the detection of the ionospheric disturbances caused by this eruption over Europe, where dense networks of both ionosondes and GNSS receivers are available. This event took place on the day of a geomagnetic storm. We show how data from different instruments and from different observatories can be combined to clearly distinguish the TIDs produced by the eruption from those caused by concurrent geomagnetic activity. The Lamb wave front was detected as the strongest disturbance in the ionosphere, travelling at between 300 and 340 m/s, consistent with the disturbances in the lower atmosphere. By comparing observations obtained from multiple types of instruments, we also show that TIDs produced by various mechanisms are present simultaneously, with different types of waves affecting different physical quantities. This illustrates the importance of analysing data from multiple independent instruments in order to obtain a full picture of an event like this one, as relying on only a single data source might result in some effects going unobserved.

Large‐Scale Disturbances in the Upper Thermosphere Induced by the 2022 Tonga Volcanic Eruption

“…Significant equatorial plasma bubbles (EPBs) and irregularity activities were observed (Aa, Zhang, Erickson, et al., 2022; Hong et al., 2022; Sun et al., 2022), and the ionospheric disturbances in the conjugate hemisphere were also suggested (Lin et al., 2022). These and other studies (Astafyeva et al., 2022; Maletckii & Astafyeva, 2022; Ghent & Crowell, 2022; K. Zhang et al., 2022; Verhulst et al., 2022) represent some significant progress in understanding the connection between volcanic activities, earthquakes and atmospheric disturbances that has been well explored historically (e.g., Astafyeva, 2019 and references therein; Cheng & Huang, 1992; Dautermann et al., 2009; Garcia et al., 2013; Hao et al., 2006; Heki, 2006; Liu et al., 1982; Nakashima et al., 2016; Roberts et al., 1982; Yang et al., 2014).…”

Multi‐Instrument Observations of Various Ionospheric Disturbances Caused by the 6 February 2023 Turkey Earthquake

“…Normally, sTEC is vertically mapped to better compare TEC time‐series for different stations and satellites. However, filtering and detrending such an uncalibrated observable would prevent the estimation of the wave amplitude since the calibration bias would be multiplied by the mapping function, causing an amplification of the wave amplitude, especially for low‐elevation angles (Verhulst et al., 2022). To prevent or somewhat limit such amplification effect, we employed NeQuick 2 (Nava et al., 2008), a climatological model that provides a TEC estimate between two given points (in our scenario, the initial GNSS station and satellite position).…”

“…To investigate the spatial behavior of the co‐seismic TID, we rely on the widely used thin‐layer ionospheric approximation (Mannucci et al., 1998), with the shell height set to 250 km. To extract the TID signature from the vTEC, we use a bandpass filter based on the novel Fast Iterative Filtering (FIF) technique (Cicone & Zhou, 2021), with the passband set from 10 to 240 s. Since the data analyzed have a time resolution of 1 and 30 s, in the latter case the filter was a highpass, with the threshold set to 240 s. FIF, can decompose non‐stationary, non‐linear signals into simple oscillatory components (Madonia et al., 2023; Verhulst et al., 2022) called Intrinsic mode functions, each defined by its quasi‐stationary frequency. By summing those modes that fall into the frequency band of interest for each time step, we extracted the detrended TEC (dTEC).…”

Multiwave Structure of Traveling Ionospheric Disturbances Excited by the Tonga Volcanic Eruptions Observed by a Dense GNSS Network in China

“…We used TEC data from a dense GNSS network in China to monitor the TIDs after the Tonga volcanic eruption. The main objectives and significance of our study can be summarized as follows: (a) After the event, the community investigated the global ionospheric response using multiple instruments in New Zealand, Australia, Japan, North America, and Western Europe (e.g., Aa et al., 2022; Harding et al., 2022; Hong et al., 2022; Lin et al., 2022; Matoza et al., 2022; Themens et al., 2022; Verhulst et al., 2022; Wright et al., 2022; Zhang et al., 2022). However, the dense Chinese GNSS data have not yet been analyzed.…”