Ionospheric Disturbances generated by 2022 Hunga Tonga-Hunga Ha'api Volcano: Comparison of GITM simulations with GNSS observations

Volcanic eruptions provide broad spectral forcing to the atmosphere and can create disturbances in the ionosphere-thermosphere (IT) system by propagation of the developed acoustic-gravity waves (AGWs). These disturbances can be observed by Global Navigation Satellite Systems (GNSS) and used to analyze various properties of the initial perturbation such as localization [1] and total energy content [2]. The focus of this study is to simulate ionospheric Total Electron Content (TEC) variations induced by 2022 Hunga Tonga-Hunga Ha’apai (HTHH) event for comparison to GNSS data. Simulations are preformed using the Global Ionosphere-Thermosphere Model (GITM) driven by inputs providing different aspects of the atmosphere’s AGW response. Simulation results from the High Altitude Mechanistic General Circulation Model (HIAMCM) are used to excite Traveling Ionospheric Disturbances (TIDs) related to secondary waves generated by the breaking of primary waves [3]. Meanwhile, simulation results from the Whole Atmosphere Community Climate Model with IT extension (WACCM-X) are used to represent TIDs generated by Lamb waves [4]. The different specifications of GITM’s lower boundary forcing are performed to compare IT disturbances induced by different primary AGW propagation mechanisms. Additionally, preliminary results include the NCAR 3DDynamo are compared.