Geophysical Research Letters: As one of the most powerful volcano eruptions on record, the Hunga Tonga-Hunga Ha'apai Volcano produces waves that ripple through the atmosphere and near space environment. These wave signals have been recorded by observations from instruments on the ground and from satellites, and they propagate around the Earth multiple times. This event provides a rare opportunity to study the strong and direct connection of the whole atmosphere system. The challenge is for a model to be able to represent the key processes in the whole atmosphere system and to have sufficient spatial and temporal fidelity to gain a realistic global picture of the event. This is achieved in study by using the high-resolution Whole Atmosphere Community Climate Model with thermosphere/ionosphere extension (WACCM-X). The model is able to simulate the global propagation of the waves, and the model results compare favorably with observations from the surface to the thermosphere and ionosphere.