A theory of ionospheric response to upward‐propagating tides: Electrodynamic effects and tidal mixing effects

摘要: [1] The atmospheric tide at ionospheric heights is composed of those locally generated and propagated from below. The role the latter in producing variability daytime ionosphere examined using National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model. impact upward-propagating tides evaluated by running simulations with without tidal forcing lower boundary (approximately 96 km), which imitates effect When migrating diurnal semidiurnal switched on, intensity E region currents upward velocity equatorial F vertical plasma drift rapidly increase. low-latitude total electron content (TEC) first increases, then gradually decreases to below initial level. increase TEC caused an enhanced fountain while subsequent decrease due changes neutral composition, are characterized a global-scale reduction mass mixing ratio atomic oxygen O1. results further numerical experiments indicate that mean meridional circulation induced dissipating thermosphere mainly responsible O1 reduction; it acts like additional turbulent eddy produces “mixing effect” enhances net downward transport loss It stressed both electrodynamic effects can be important density. Since two mechanisms act different ways on time scales, response actual highly variable expected complex.