Ground-based Measurements of Ionospheric Phenomena Associated with the Equatorial Electrojet

Abstract

The paper first describes the morphology of the equatorial electrojet current at different latitudes. The effects of geophysical disturbances like solar flares and geomagnetic storms as well as the regular changes like lunar tidal effects on the electrojet currents are then reviewed. The effects of equatorial electrojet on the horizontal and vertical drifts in the ionosphere near the magnetic equator and on the occurrence of sporadic E reflections near the magnetic equator are discussed. The origin of equatorial anomaly in the F₂-region and the diurnal variation of <i>f</i>_oF₂ at low latitudes are shown to be directly related to the electrojet. The storm time and the lunar diurnal variation in the F₂-region at low latitudes are found to be sympathetic to the corresponding variations in the electrojet. It is concluded that the F₂-region between ±30° dip as well as the E-region between ±7° dip is very closely connected with the equatorial electrojet currents.