Asian Journal of Scientific Research1992-14542077-2076Asian Network for Scientific Information10.3923/ajsr.2009.155.160SomoyeE.O. 3200923NmF2 variability, VR, at Ibadan (7.4°N, 3.9°E, 6°S dip) is investigated for diurnal and seasonal changes during low, moderate and high solar activity. It is also compared with those of Singapore (1.3°N, 103.8°E, 17.6°S dip) and Slough (51.5°N, 359.4°E, 66.5°S dip). NmF2 absolute VR (and not only relative VR) is greater during the night and slightly greater around noon than during other daytime hours. While, daytime NmF2 shows no seasonal variation, night time NmF2 is greater during the equinoxes at low and moderate solar activity and during the equinox and June solstice at high solar activity. Daytime VR found not to show latitudinal difference during moderate solar activity is observed to increase with latitude during high solar activity. Nighttime VR is found to decrease with latitude during high solar activity. While, NmF2 VR at Ibadan and Singapore are found to decrease alternately with sunspot number, R, that of Slough is observed to increase with R during about the first half of the day and to decrease with R during the other part.]]>Amarante, G.M., M.C. Santamaria, M.M. de Gonzalez, S.M. Radicella and R. Ezquer,20043418781886Bilitza, D., O.K. Obrou, J.O. Adeniyi and O. Oladipo,2004foF2 in the equatorial ionosphere.]]>3419011906ITU-R,1997Kouris, S.S. and D.N. Fotiadis,200229977985Rishbeth, H. and O.K. Garriot,1969Rishbeth, H. and M. Mendillo,20016316611680Somoye, E.O.,2009foF2 at Ibadan.]]>4111114