Analysis of Secular Variations of Earth's Magnetic due to Equatorial Electrojet Field Measured at Ecuadorian Geomagnetic Station.

In this study, we have used the Earth magnetic field (MG) data provided by the ground-based MAGDAS instrument at Jerusalem (JRS) station, located in Ecuador, above the geographic equatorial line. To study the variation of the declination angle, the variation the magnitude of Earth's magnetic field and the secular variation of the horizontal component of MG. The variation of the declination of the magnetic field presents a linear tendency as function of time at JRS station with a variation of -0.1647 ° per year. The total Earth's magnetic field, from 06-2014 to 12-2016, shows a linear tendency as function of time weakening with a rate of 91 (nT) per year. We found that the principal frequencies of the variation of horizontal field are f1=1,16*10(-5) [Hz], f2=2,31*10(-5) [Hz], f3=3,4722*10(-5) [Hz] and f4=4,6296*10(-5) [Hz]. Those frequencies are equivalent to periods of 24, 12, 8 and 6 hours respectively. We found also the presence of a semiannual variation of Sq that is maximized during the months of the equinoxes and minimized during solstice months.