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The massive explosive eruption of the Hunga volcano on 15 January 2022 generated atmospheric waves that were recorded around the globe and affected the ionosphere. The paper focuses on observations of atmospheric waves in the troposphere and ionosphere in Europe, however, a comparison with observations in East Asia, South Africa and South America is also provided. Unlike most recent studies of waves in the ionosphere based on the detection of changes in the total electron content, this study builds on detection of ionospheric motions at specific altitudes using continuous Doppler sounding. In addition, much attention is paid to long-period infrasound (periods longer than ∼50 s), which in Europe is observed simultaneously in the troposphere and ionosphere about an hour after the arrival of the first horizontally propagating pressure pulse (Lamb wave). It is shown that the long-period infrasound propagated approximately along the shorter great circle path, similar to the previously detected pressure pulse in the troposphere. It is suggested that the infrasound propagated in 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 pulse from the Hunga eruption is also discussed. Doppler sounders in East Asia, South Africa and South America did not record such a significant TID. However, TIDs were observed in East Asia around times when Lamb waves passed the magnetically conjugate points. A probable observation of wave in the mesopause region in Europe approximately 25 min after the arrival of pressure pulse in the troposphere using a 23.4 kHz signal from a transmitter 557 km away and a coincident pulse in electric field data are also discussed. [ABSTRACT FROM AUTHOR]

The synchronous response of the lower and upper ionosphere to the propagation of the atmospheric Lamb wave and tsunami that were generated by the mega-eruption of the Hunga submarine volcano on January 15, 2022, has been studied for the first time using data from very low frequency radio sounding in the Far East area of Russia and the Japanese–Australian network of receivers of global navigation satellite system signals. It has been found that wave-like variations of very low frequency and global navigation satellite system signals not only appear at the intersection of radio paths by Lamb waves and tsunamis but also demonstrate nonlocal effects owing to the geomagnetic field. Such variations are caused by the action of internal gravity waves generated by these sources and the dust component of eruption on the ionosphere. The energy of the main eruption has been estimated and detected ionospheric perturbations have been interpreted. [ABSTRACT FROM AUTHOR]