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

Via the Fourier spectral diagnostics and least squares fittings, the [21h, W2] and [13h, 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 similar to 50% in the NmF2) 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 [11h, W3] child wave is explicit as well. Although the [29h, 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 [29h, W0] child wave shows up in the NmF2.