LUNAR VARIATIONS IN F2-REGION OF IONOSPHERE AT LOW LATITUDES

The suggestion by Martyn that the lunar tidal variations of the electron concentration in the F-region near the magnetic equator are due to the superposition of a small (lunar) vertical velocity on a large (solar) velocity is exterrded to examine the lunar variations in the F2-region over the range of latitudes within 25° of the magnetic equator. Because the form of the equatorial anomaly is modified by the lunar component, the lunar variations in electron density show a large latitudinal dependence. The variations of various F-region parameters have been calculated assuming equilibrium conditions and a comparison with experimental data shows that most of the observed features can be explained satisfactorily. © 1969.