Secondary gravity waves generated after the Tonga volcano explosion and its effect on the ionosphere

This work reports on the ionospheric effects observed in New Zealand, Australia, and South America due to the Tonga volcano (20° S; 175° W) explosion on January 15, 2022, which first occurred around 04:00-4:15 UT. To observe the ionospheric effects at these locations, approximately 1000 GNSS receivers were used to calculate the detrended total electronic content (dTEC) and the TEC rate index (ROTI). After 1.0 - 1.5 hour after the explosion, traveling ionospheric disturbances (TIDs) were observed over New Zealand with a horizontal wavelength (λ_H) of 1300 km, horizontal phase velocity (C_H) of 551 m/s, period (τ) of 39 min, and propagation direction (α) of 210° (clockwise from north). In addition, we observed ionospheric scintillations through ROTI of the order of 0.6-0.7 TECU/min at the same time as TIDs. On the other hand, in Australia, TIDs were observed 3 hours after the explosion with λ_H, C_H, τ, and α of 861 km, 478 m/s, 30 min., and 266°, respectively. Finally, in South America, 8 hours after the explosion, we observed TIDs with the following characteristics: λ_H between 348 and 1174 km, C_H of 294 - 515 m/s, τ of 19 - 36 min., and α of 32°. Between 18:00 UT and 19:00 UT, we also observed TIDs over South America with λ_H of 330-505 km, C_H of 275 - 350 m/s, τ of 20 - 24 min., and α of 32-139°. Also, we observed ionospheric scintillations over Chile and Argentina of the order of 0.5 TECU/min during the TIDs passage. Regarding the TIDs, we will also discuss using ray tracing and The High Altitude Mechanistic general Circulation Model (HIAMCM) to model the primary GWs created from the explosion, how they break and generate body forces which then create secondary gravity waves that propagate in the ionosphere.