• Onujagbe, I. P.
  Physics Unit, School of Preliminary Studies, Kogi State Polytechnic, Lokoja, Nigeria
  




• Ahmed-Ade, F.
  Department of Physics, Federal University Lokoja, Nigeria
  




• Mopah, M.
  Science Laboratory Department, Kogi State Polytechnic, Lokoja, Nigeria
  




• David, A. J.
  Physics Unit, School of Preliminary Studies, Kogi State Polytechnic, Lokoja, Nigeria
  

The surface radio refractivity, refractivity gradient at 1km above ground surface and the effective earth radius factor, K over Akure and Ondo town of South west Nigeria has been investigated using Ten (10) years daily data of the meteorological parameters of Pressure, air temperature and humidity. The result showed that the mean monthly value of the surface refractivity at the Ondo station is generally slightly higher than that of Akure. The monthly mean value of refractivity at the two stations was found to be strongly correlated with a value of 0.915. The most negative refractive gradient value observed at Ondo and Akure are of -46.48N-units/km and -45.64N-units/km respectively and the least effective earth radius factor, k value of 1.421 and 1.410 were observed at the station respectively. These results showed that the Ondo and Akure station were generally super-refractive. The Ondo station was however found to be slightly more super-refractive than the Akure station.