Non-migrating tides in the ionosphere-thermosphere: In situ versus tropospheric sources

The National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM) is utilized to quantify these tides, and to assess their importance relative to those that propagate upward from lower atmospheric regions.

The primary diurnal tides excited in situ by the above mechanism include DE1, D0 and DW2, with zonal wind amplitudes on the order of 20 m s⁻¹ (5–10 m s⁻¹) at ∼500 km (∼350 km) under solar maximum (minimum) conditions. Smaller amplitude semidiurnal non-migrating tides, mainly SE1, S0, SW1, and SW3, are also generated under solar maximum conditions. The aggregate effect of these tidal components is to produce extrema ranging from −110 to +140 m s⁻¹ in a typical illustration of latitude versus longitude at a constant local time.