SOME EFFECTS OF NEUTRAL AIR WINDS ON IONOSPHERIC F-LAYER

The ionospheric continuity equation for the F2-layer and the equation of motion of the neutral atmosphere have been solved simultaneously to calculate diurnal variations of F2-layer critical frequency and height at different latitudes for summer, equinox and winter conditions. The agreement between the calculated and observed f{hook}0F2 variations is reasonable for daytime conditions, but the night-time calculated values are generally too small. The anomalous F2-layer behaviour observed at high latitudes in summer, and also the variation of the height of the layer peak at middle latitudes, appear to be satisfactorily explained by neutral air winds. These winds are also shown to be responsible for the evening enhancements observed at middle latitudes in summer. Relatively slight changes in the atmospheric model used in the calculations can result in very different diurnal variations of calculated critical frequency. © 1968.