High-altitude responses to tsunami forcing: 2. Response of the ionosphere to gravity waves

Abstract:

The NRL first-principles ionosphere model SAMI3/ESF is used to study the ionospheric effects associated with tsunami-driven gravity waves. We consider two gravity wave models: spectral and nonlinear. It is shown that gravity-wave induced variations in the neutral wind lead to plasma variations both perpendicular and parallel to the geomagnetic field, and that these variations are a function of gravity wave propagation direction relative to the geomagnetic field. In addition we find that the ionosphere response is affected by altitude range of the gravity waves; specifically whether or not the gravity waves penetrate above the F peak. It is found that the TEC exhibits variations +/- 0.15 TECU and the 6300A airglow emission variation is up to +/- 2.5% relative to the unperturbed background airglow, consistent with observations.