Studying the global propagation of gravity waves generated by the Hunga Tonga-Hunga Ha‘apai volcanic eruption from meteor radar observations and the High-Altitude General Mechanistic Circulation Model

The Hunga Tonga-Hunga Ha‘apai (HTHH) volcanic eruption on 15th January 2022 was an unprecedented event and a unique opportunity to investigate volcanic-caused gravity waves (GW) and their global propagation. In this study, we have combined all the available meteor radar observations and data analysis to identify the HTHH GW in the observations. Our results are compared to model-based wind perturbations from HIAMCM of secondary waves that are forced by the GW model MESORAC using GOES-17 observations. Furthermore, we leverage the GW polarization relations to identify different wave features in the observations and perturbation runs with HIAMCM. There is a remarkable agreement in the observed phase speeds for the eastward and westward GW propagation between the observations and HIAMCM wind perturbations indicating that the mesospheric HTHH GW are explainable by secondary waves generated by breaking of the primary GWs from the eruption. We also shed some light on the importance of the quasi-2-day wave on the HTHH GW propagation.