Estimation of Tropospheric Radio Refractivity and Its Variation with Meteorological Parameters over Ikeja, Nigeria

Abstract

Estimation of radio refractivity is critical in the planning and design of radio links/systems for the purpose of achieving optimal performance. This present work investigates the tropospheric radio refractivity over Ikeja, Lagos State, South Western, Nigeria (Latitude 6.58°N, Longitude 3.33°E and altitude 40 m above sea level) and the sensitivity of radio refractivity due to meteorological parameters of monthly average daily atmospheric pressure, relative humidity and temperature for a period of 12-years. The statistical estimation of tropospheric radio refractivity has been evaluated using the method recommended by the International Telecommunication Union (ITU). The result indicated that the radio refractivity during the rainy season is greater than the dry season. It         was observed that the maximum average value of radio refractivity of 389.45 N-units and    minimum average value of 373.04 N-units occurred during the rainy and dry seasons in the   months of April and January respectively. The dry term contributes 67.98% to the total value of the radio refractivity while the wet term contributes to the major variation. The average refractivity gradient computed for the study area under investigation was N-units/km and the     average effective earth radius (k – factor) was 1.39 which corresponds to the conditions of super-refraction.