Near-Real-Time Analysis of the Ionospheric Response to the 15 January 2022 Hunga Tonga-Hunga Ha'apai Volcanic Eruption

摘要

We present a near-real-time (NRT) scenario of analysis of ionospheric response to the 15 January 2022 Hunga Tonga-Hunga Ha'apai eruption by using Global Navigation Satellite Systems data in the near-field (in the vicinity of the volcano), and in the far-field (Japan, North America, and South America). We introduce a new method to determine instantaneous velocities using an interferometric approach and using the time derivative of the total electron content (TEC). Moreover, for the first time, we propose a novel method that automatically estimates the apparent propagation velocity of ionospheric disturbances from NRT travel-time diagrams. By using our new methods, we analyzed the dynamics of co-volcanic ionospheric disturbances generated by the Hunga-Tonga eruption, and we estimated the first propagation velocity in the near-field to be ~800–950 m/s, subsequently decreasing to ~600 m/s. Based on these values, we conclude that in the near-field, we detect ionospheric signatures of acoustic waves. In the far field, the apparent velocity of ionospheric disturbances was estimated to be between 277 and 365 m/s, which corresponds to the propagation of the Lamb wave. It is important to note that our new methods can successfully perform at low spatial resolution networks and with 30-s cadence data. Also, they enable NRT spatio-temporal analysis of ionospheric TEC response to smaller-amplitude events.