Variability of Microwave Radio Refractivity and Field Strength over Some Selected Locations in Nigeria

In this study, results of the variation of radio field strength derived from the computation of surface refractivity through measurements of temperature, relative humidity and pressure across seven locations ((Akure (7.15°N, 5.12°E), Lagos (6.30°N, 3.20°E), Abuja (7.10°N, 9.25°E), Jos (9.50°N, 8.50°E), Makurdi (7.30°N, 8.53°E), Port-Harcourt (4.20°N, 7.00°E), and Nsukka (6.90°N, 7.67°E)) in Nigeria are presented. Two years (Jan., 2011–Dec., 2012) archived data as provided by Tropospheric Data Acquisition Network (TRODAN) of the Centre for Atmospheric Research, Anyigba, Kogi State were utilized for the study. Results showed that the values of surface refractivity (Ns) were low during the dry season months and high during the wet season months and also there was high values of NS at the coastal areas compared with the inland areas. It was also deduced that the average value of NS for Abuja, Akure, Jos, Lagos, Markurdi, Nsukka and Port-Harcourt is 355, 362, 303, 391, 375, 361 and 399 N-units respectively. Also the average values of Field Strength Variability (FSV) are 30.38, 20.16, 21.39, 24.21, 24.31, 21.49, and 21.48 dB in the respective locations and that the FSV values were high during the dry season months and low during the wet season months. This may be attributed to the prevalence of high temperature during dry season and low temperature during the wet season.