Mean solar quiet daily variations in the earth’s magnetic field along East African longitudes

Solar quiet daily (Sq) variation in the earth’s magnetic field along the East African meridian was studied using data of the H, D and Z components recorded with Magnetic Data Acquisition System of SERC. One year data recorded at ten African geomagnetic observatories was used in the analysis of worldwide solar quiet daily variation (Wsq). The study revealed that the focus of Sq (H) in the southern hemisphere lies at the boundary of low and middle latitude region. Noon-time enhancement of Sq (H) was generally noticed at all stations along the meridian, though it is latitudinal dependent in terms of magnitude as it reduces with distance from dip equator. In addition, night-time variations also occur in small magnitude along African meridian in Sq (H) and Sq (Z) which could be attributed to non-ionospheric sources. Semi-diurnal variation was noticed in Sq (D) at all stations except in AAB that is under the influence of electrojet current. Dusk sector calm condition of Sq (D) current was notice in some stations and the same condition was also noticed at dawn sector in some other stations. The usual sunrise maximum and sunset minimum for D component at stations north of dip equator as well as sunrise minimum and sunset maximum was found to increase with distance away from dip equator. Day-time perturbation of Sq current was noticed to be more pronounced in all the three field elements. Mass plots of annual mean hourly value show contrasting phase pattern about the focus in H element and the results of the variations at each region with the associated standard error. It was concluded from the result of correlation coefficients computed that different currents system flowing in opposite directions could be responsible for contrasting patterns.