Analysis of Radio Refractivity Variations Across Geographical Coordinates of Nigeria

Radio refractivity variations across geographical coordinates of Nigeria has been studied using relative humidity, air pressure and air temperature data from 2012 to 2013 obtained from archives of Nigeria Air Space Development Research Agency, Department of meteorological Service, Oshodi, Lagos and Department of Pure and Applied Physics, Ladoke Akintola University of Technology, Ogbomoso, automated weather station. Using regression analysis technique on the data obtained, a model was developed which established the relation between average annual surface radio refractivity and latitude across geographical coordinates of Nigeria. The results from the model have shown that average annual radio refractivity decreases with increase in latitude across Nigeria from the Tropical wet climate via Savanna North to the Semi-arid climate. The computed values of the refractivity gradient for the period of years under study showed that both Tropical wet and Savanna North climates were super-refractive in the first 1km above the sea surface while the Semi-arid was sub-refractive except Yola which is exceedingly close to the Savanna North. Keywords: Radio refractivity, Geographical coordinate, Regression technique, Mode