Volume 4, Issue 1


Aghogho Ogwala1, Emmanuel Somoye2, Oluwole Oyedokun3, Rasaq Adeniji-adele4, Eugene Onori5, Oluwafunmilayo Ometan6, Abiola Ogungbe7, Cornelius Ogabi8, Olujimi Adejo9, Kayode Oluyo10, and Adesina Sode11
1Lagos State University, Ojo, Nigeria, 2Lagos State University, Ojo, Nigeria, 3University Of Lagos, Nigeria, 4Lagos State University, Ojo, Nigeria, 5Lagos State University, Ojo, Nigeria, 6Lagos State University, Ojo, Nigeria, 7Lagos State University, Ojo, Nigeria, 8Lagos State University, Ojo, Nigeria, 9Lagos State University, Ojo, Nigeria, 10Lagos State University, Ojo, Nigeria, and 11Lagos State University, Ojo, Nigeria


Total electron content (TEC) is a parameter of the ionosphere that produces great effect on radio signals. We present the diurnal and seasonal variations of vertical total electron content (vTEC) during the ascending phase of solar cycle 24. A moderate solar activity year (2011) with sunspot number, Rz = 55.7 is used in this study. Total electron content (TEC) deduced from the dual frequency GPS measurements obtained at two ground stations namely: ABUZ (Zaria) with longitude 7.39oE in the north and UNEC (Enugu) with longitude 7.30oE in the south are considered. Both stations are located within the same longitude and has a latitudinal difference of 4.74o in the Nigerian equatorial ionosphere (NEI). Comparison of diurnal and seasonal variations of TEC is carried out for both stations. The diurnal variation of TEC shows a steep increase starting from sunrise, reaching daytime maximum between 13 – 15 LT at UNEC and 14 – 16 LT at ABUZ, then falls to a minimum at sunset. Dawn depression occurred at the same local time of 04 LT at both stations. On a seasonal scale, Pre- and post-midnight values were highest during the Equinoxes, followed by December solstice and least in June Solstice season at ABUZ. Pre- and post-midnight values were also higher during the Equinoxes than the Solstice season at UNEC, although they are about the same range. Also, TEC values are observed to be slightly higher for all hours and seasons at Enugu in the south than Zaria in the north except during March equinox at Zaria where TEC values were higher during the daytime. This implies that there could be little variations in TEC even within the same latitudinal zone.

Keywords: TEC, Diurnal, Seasonal, and Variability

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