Tonga eruption triggered waves propagating globally from surface to edge of space
Corwin J. Wright, Neil P. Hindley, M. Joan Alexander, Mathew Barlow, Lars Hoffmann, Cathryn N. Mitchell, Fred Prata, Marie Bouillon, J. N. Carstens, Cathy Clerbaux, Scott Osprey, Nick Powell, C. E. Randall, Jia Yue
Abstract
The January 2022 Hunga Tonga–Hunga Haʻapai eruption was one of the most explosive volcanic events observed in the modern era, producing a vertical plume which peaked more than 50km above the Earth. The initial explosion and subsequent plume triggered atmospheric waves which propagated around the world multiple times. Here, we combine a comprehensive set of satellite and ground-based observations to analyse and quantify this wave response, from surface to ionosphere. A broad spectrum of waves was triggered by the initial explosion, including Lamb waves propagating at 318.2±6 ms-1 at surface level and between 308±5 to 319±4 ms-1 in the stratosphere, and fast gravity waves propagating at 238±3 to 269±3 ms-1 in the stratosphere. Atmospheric gravity waves at sub-ionospheric heights have not previously been observed propagating either at this speed or over the whole Earth from a single identifiable source. Latent heat release from water and hot ash in the plume remained the most significant individual gravity wave source at any location for the next 12 hours, producing circular wavefronts visible across the Pacific basin in satellite gravity wave observations. A single source dominating such a large region is also unique in the observational record. The Hunga Tonga eruption represents a key natural experiment in how the atmosphere responds to a sudden point-source-driven state change, which will be of significant use for improving atmospheric weather and climate models.