Atmospheric and ionospheric disturbances in Europe induced by Hunga eruption on 15 January 2022

The massive explosive eruption of the Hunga Tonga volcano on 15 January generated atmospheric waves that were comparable with those generated by the Krakatoa 1883 eruption. The waves were recorded around the globe and affected also the ionosphere. We focus on observation of atmospheric waves in the troposphere and ionosphere in Europe. The tropospheric waves are studied using a large aperture array of microbarometers and the ionospheric disturbances are detected using continuous Doppler sounding. It is shown that long-period infrasound (periods longer than ~50 s) is observed simultaneously in the troposphere and ionosphere about an hour after the arrival of the first pressure pulse (Lamb wave) in the troposphere. Data analysis confirms propagation approximately along the shorter great circle path both for the infrasound and the Lamb wave. It is suggested that the infrasound propagated into the ionosphere probably due to imperfect refraction in the lower thermosphere. The observation of infrasound in the ionosphere at such large distances from the source (over 16 000 km) is rare and differs from ionospheric infrasound detected at large distances from the epicenters of strong earthquakes, because in the latter case the infrasound is generated locally by seismic waves. An unusually large traveling ionospheric disturbance (TID) observed in Europe and associated with the pressure wave from the Hunga Tonga eruption is also discussed. In addition, a probable observation of wave in the mesopause region approximately 25 min after the arrival of pressure pulse in the troposphere using a 23.4 kHz signal from a transmitter 557 km away is shown.