Ionospheric Response to Infrasonic-Acoustic Waves Generated By Natural Hazard Events

摘要: Recent measurements of GPS-derived total electron content (TEC) reveal acoustic wave periods ∼1–4 min in the F region ionosphere following natural hazard events, such as earthquakes, severe weather, and volcanoes. Here we simulate ionospheric responses to infrasonic-acoustic waves, generated by vertical accelerations at Earth's surface or within lower atmosphere, using a compressible atmospheric dynamics model perturb multifluid model. Response dependencies on source geometry spectrum are investigated middle, low, equatorial latitudes. Results suggest constraints amplitudes that consistent with observations provide insight geographical variability TEC signatures their dependence velocity field perturbations relative ambient geomagnetic field. Asymmetries poleward equatorward from sources indicate enhanced side while aligned currents driven principally side, due alignments velocities parallel perpendicular lines, respectively. Acoustic-wave-driven shown have ∼3–4 min, which fraction remains strong dissipation throughout thermosphere. Furthermore, thermospheric waves couple ion sound topside ionosphere, driving plasma disturbances similar faster phase speeds. The associated magnetic simulated calculated be observable may new observational addition provided GPS measurements.