This study investigates the possible occurrence of counter equatorial electrojet (CEJ) and a quicker method for identification of CEJ. Data from a chain of magnetic observatories of World Data Center for Geomagnetism in Tokyo, Japan, was employed. It is strikingly interesting to observe that most CEJ occurred from morning through new dusk, with almost the same pattern of dHin depression. In Ascension Island (ASC), Huancayo (HUA) and Pondicherry (PND), most ∆H were found to be less than zero, which reveals an indication of full CEJ. Partial CEJ occurrences were observed during some hours at these stations where ∆Hin >0. It is suggested that IMF turning north indicates CEJ, hence storm effects could also be attributed to CEJ existence. Some of our new findings are at variance with results of some previous workers; hence further work is suggested for further clarification. A quick method of easy identification of CEJ is suggested.

A comprehensive study of Solar Flare Effects (SFE) across latitudes has been carried out using an extensive data set of two geomagnetic elements H and Z selected from 1997 to 2005. The X (intense) and M (medium) solar flares were examined under quiet conditions. Nine stations extending from equatorial to high latitudes were used in the study. Data employed in this work include minute data of geomagnetic field, solar flare and hourly data of geomagnetic field. On the whole, about one hundred and fifty four (154) solar flares were selected. Each of these flares was critically studied and analyzed to see its response on the geomagnetic H and Z components. Only fifteen to thirty four flares showed the signature in the different stations. The study revealed that pre-solar flare and solar flare amplitude variations are least in the mid latitude stations, followed by the equatorial and low latitude stations and the highest in the high latitude stations. The pre-solar flare amplitude variations and solar flare amplitude variations of Z failed to show any clear pattern. Correlation existed between the solar flare amplitude variations of H and the pre-solar flare amplitude variations. The ratios of ∆H SFE /∆Ho and ∆Z SFE /∆Zo were greater than zero for all the stations used in the study. This implies that the solar flare effects enhance geomagnetic field across latitudes.

Predicting the arrival time of Coronal Mass Ejections (CMEs) with a lower value of average error of the difference between the predicted and the observed transit time is very crucial in space weather forecast. A modified Empirical Coronal Mass Ejection Arrival (ECA) model was proposed, namely, OjihOkeke modified ECA model to predict the transit time of twenty eight fast CMEs from the sun to the earth. This is the first time the Ojih-Okeke modified ECA model is being applied in prediction of transit time of CMEs from the sun to the earth. The proposed modified model was tested using data obtained from coronagraph observations of large angle spectrometric aboard, the Solar and Heliospheric Observatory (SOHO/LASCO) CME catalogue from the period of 1997 to 2015. To ascertain the accuracy of the modified model, the three ECA model of Gopalswamy (G2000, G2001, and VG2002) were applied to our data points. Linear regression analyses were carried out on the data points and scatter plots were generated using excel software package. The average error of the difference between the CMEs transit time and models predicted transit time with their fractional errors were 4.27 h and 0.10 for the Ojih-Okeke modified model; 10.36 h and 0.23 for the VG2002 model; 12.93 h and 0.29 for G2001 model; and 14.42 h and 0.32 for the G2000 model. The proposed modified model has proved very effective in prediction of arrival time of CMEs. It is our recommendation that future work on prediction of the arrival time of CMEs be carried out employing our modified ECA model.

It has been established that Coronal Mass Ejections (CMEs

Solar quiet (Sq) daily currents variation obtained in the Hermanus (34.34 o S, 19.22 o E), Tsumeb (19.24 o S, 17.72 o E), Hartebeesthoek (25.68 o S, 28.09 o E) and Maputo (25.97 o S, 32.57 o E), were employed in determining the mantle electrical conductivity depth profile of the Southern African region. The external and internal contributions in the solar quiet field were separated using the spherical harmonic analysis (SHA), after which, the transfer functions were used to compute the electrical conductivity depth profiles of the region. A downward increase was observed in electrical conductivities and deep depth of penetration within the Earth regions. In Hartebeesthoek, Hermanus, Maputo and Tsumeb, the evaluated average electrical conductivity values are 0.028 Sm -1 , 0.039 Sm -1 , 0.057 Sm -1 and 0.0.025 Sm -1 at depths of 76.4 km, 84.1 km,141.0 km and 111.5 km at the respective maximum depths of penetration of 1052.8 km, 1467.0 km, 1160.8 km and 1289.5 km in Hartebeesthoek, Hermanus, Maputo and Tsumeb, the calculated electrical conductivity reached the maximum values of 0.498 Sm -1 , 0.323 Sm -1 , 0.387 Sm -1 and 0.187 Sm -1 respectively. Discontinuities were observed in all the profiles but are more prominent in Tsumeb region near 390.0 -750.0 km, 820.0 -980.0 km and 200.0 -300.0 km. From these results, we are stating that the effects from the deeper 3-D structures (such as gold, copper etc), the hydrated transition zone and effect from the ocean contribute to the greater depth of Sq penetration.