On the Propagation of Traveling Ionospheric Disturbances From the Hunga Tonga-Hunga Ha'apai Volcano Eruption and Their Possible Connection With Tsunami Waves

We report our analysis of ionospheric disturbances from the 15 January 2022 Tonga volcano eruption, using GPS data from the International GNSS Service network and ionosonde data in the Australian sector. Wave fluctuations with amplitudes of similar to 1 TECU and altitude variations of similar to 100 km were observed in the GPS and ionosonde data, respectively. In near-field region around Tonga shortly after the eruption, our analysis reveals that the ionospheric disturbances had an azimuthally anisotropic velocity profile, with a peculiar minimum in southwestward direction. Close resemblance is identified between the velocity profile of near-field ionospheric disturbances and the Tonga tsunami, suggesting a coupling between water and atmospheric waves. In far-field, the disturbances propagated at similar to 300 m/s, circling the globe for at least three days and possibly until 21 January 2022, in agreement with several previous reports of the event. Arrival times of ionospheric disturbances observed by GPS receivers and ionosondes provide consistent picture.