Study of average seasonal variations of surface radio refractivity across some selected cities in Nigeria
The average seasonal variations of surface radio refractivity based on measurement of atmospheric pressure, temperature and relative humidity made across Yola (9o11' N, 12o30' E), Anyigba (7o 45' N, 6o45' E), Lagos (6o 27' N, 5o12' E), and Port-Harcourt (4o 48'N, 7oE) Nigeria, is reported. The measurement was made using wireless automatic weather station installed at the surface of each station under study. The study utilized three years of meteorological data measured from January 2010 to December 2013 to calculate the surface radio refractivity using empirical formula recommended by the International Telecommunication Union (ITU-R 453, 2012). The result shows that the average value of surface radio refractivity showed seasonal variations with high values during the rainy season and low values during the dry season with an increase in the value of surface radio refractivity of 242N units at Anyigba station to a maximum value of 384-N units at Lagos station. The result also shows that climatic condition is the force behind the seasonal variations of surface radio refractivity in all study stations.
Keywords: Refractivity, Temperature, Atmospheric pressure, Relative Humidity