The Mesoscale Gravity Wave Response to the 2022 Tonga Volcanic Eruption: AIRS and MLS Satellite Observations and Source Backtracing

On 15 January 2022, the Hunga Tonga-Hunga Ha'apai volcano erupted violently. This exceptional event excited a manifold of atmospheric waves. Here, we focus on the mesoscale part of the wave spectrum. About 8.5 hr after the eruption a strong atmospheric gravity wave (GW) was observed in the stratosphere by the satellite instruments Atmospheric Infrared Sounder (AIRS) and Microwave Limb Sounder (MLS) in the vicinity of Tonga. By ray-tracing, we confirm the eruption as the source of this GW event. We determine the wave characteristics of the GW in terms of horizontal and vertical wavelengths and GW momentum flux. The strength of the GW is compared to the usual Southern Hemisphere flux values during this week. The event is comparable to the strongest convective events considering MLS, and exceptionally strong considering AIRS, which observes faster waves only.