Abstract

The hourly and seasonal variation of radio refractivity was studied using NECOP (Nigeria Environmental Climate Observing Program) data in Anyigba station north central Nigeria. Also, a harmonic analysis model was used to predict hour-to-hour radio refractivity in the station considered. This study uses the 5 minutes data obtained from campbell Automatic Weather Stations located in Kogi State University, Anyigba at latitude 7°17ˈ55.90ˈˈN, longitude 6°49ˈ47.02ˈˈE and altitude of about 420 m above sea level. The results of the investigation showed that the value of surface refractivity varies from 325.27 N-units in dry season to 359.59 N-units in wet season; which indicates that the wet season refractivity is greater than the dry season refractivity. This could be attributed to the amount of water vapour or relative humidity being high during the wet season in the atmosphere. Furthermore, the result of the harmonic analysis showed that the model estimate is a good fit to the surface refractivity as it produces very close value of average mean and standard deviation of the actual value of refractivity in Anyigba. Therefore, knowledge of refractivity trend in wet season and dry season is very significant in designing efficient and effective radio communication links in regions with similar climatic characteristics.