摘要：EE-index (EDst, EUEL), has been used to study the longitudinal dependence and seasonal variation of the equatorial electrojet (EEJ). The EUEL data eliminates many sources of disturbances by subtracting the median value of horizontal component (H) and the E Dst from H component data. EUEL data at a chain of stations along the dip equator have been analyzed to provide a detailed study on the equatorial electrojet. Data from eight stations (ANC, ILR, AAB, TIR, LKW, BCL, DAV and YAP stations) have been used for a period of three years (2009, 2010 and 2011). The longitudinal dependence has been studied for each year, a very good agreement between each year results has been found. This study shows that the magnetic signature of the EEJ is stronger in South America with a maximum at about longitude 77°W; and weaker in Asia, with a minimum in India, between longitudes 70°E and 90°E. The seasonal variations of the equatorial electrojet have been studied by both the whole data set (disturbed and quiet days) and quiet days’ data. It has been proved that there is a semiannual variation in the equatorial electrojet with equinoctial maxima.
