Lunar perturbations in geomagnetic field and in the characteristics of F-region over huancayo

Abstract

The lunar daily (L) and lunar monthly (M) variations in horizontal magnetic field (H), maximum electron density (N_max), height of peak ionisation (h_max ), semi-thickness (y_m ) of the F₂ layer and total electron content (N_t ) at Huancayo for the period January 1960 to December 1961 are described. The lunar tidal variations in h_max follow sympathetically the variations inH such that an increase of magnetic field causes the raising of height of peak ionisation. Lunar tides in N_max are opposite in phase to that of h_max with a delay of about 1-2 hours, suggesting that an increase of height causes a decrease in maximum electron density. The lunar tides in semi-thickness are very similar in phase to that in h_max . The lunar tidal effects in any of the parameters are largest in D-months and least in J-months. The amplitude of lunar tides in maximum electron density seems to increase with increasing height whereas the phase seems to be constant with height. It is concluded that lunar tides in the ionospheric parameters at magnetic equator are greatly controlled by the corresponding geomagnetic variations.