Physics-based Modeling of Ionospheric Signatures Induced by Surface Disturbances

Natural hazards like tsunamis, earthquakes, and volcanic eruptions can disturb the surface of the solid Earth or ocean, generating acoustic-gravity waves propagating upward through the atmosphere and inducing total electron content (TEC) disturbances in the ionosphere. To capture this process, we have developed a three-dimensional, time-dependent, and physics-based model WP-GITM (Wave Perturbation - Global Ionosphere-Thermosphere Model). WP-GITM consists of two dynamically coupled components: 1) an analytical model that solves for atmospheric acoustic-gravity waves at 100 km altitude given ground or ocean displacements; and 2) the first-principles model GITM that describes the responses of the upper atmosphere between 100 km and 600 km altitudes. We report recent WP-GITM developments and simulations of actual earthquake and tsunami events. We validate the simulated TEC perturbations through Global Positioning System (GPS) observations and have found reasonable agreement. As an advanced modeling tool, WP-GITM can provide many insights of ionospheric signatures generated by a variety of natural hazards.