Short‐term variability in the ionosphere due to the nonlinear interaction between the 6 day wave and migrating tides

Abstract

Abstract Using the thermosphere‐ionosphere‐mesosphere electrodynamics general circulation model simulations, we investigate the short‐term ionospheric variability due to the child waves and altered tides produced by the nonlinear interaction between the 6 day wave and migrating tides. Via the Fourier spectral diagnostics and least squares fittings, the [21 h, W2] and [13 h, W1] child waves, generated by the interaction of the 6 day wave with the DW1 and SW2, respectively, are found to play the leading roles on the subdiurnal variability (e.g., ±10 m/s in the ion drift and ~50% in the N m F 2 ) in the F region vertical ion drift changes through the dynamo modulation induced by the low‐latitude zonal wind and the meridional wind at higher latitudes. The relatively minor contribution of the [11 h, W3] child wave is explicit as well. Although the [29 h, W0] child wave has the largest magnitude in the E region, its effect is totally absent in the vertical ion drift due to the zonally uniform structure. But the [29 h, W0] child wave shows up in the N m F 2. It is found that the N m F 2 short‐term variability is attributed to the wave modulations on both E region dynamo and in situ F region composition. Also, the altered migrating tides due to the interaction will not contribute to the ionospheric changes significantly.