Variation of meteorological parameters and its effect on refractive index of air over Lagos Nigeria
Variations of meteorological parameters affect the refractive index in the lower atmosphere. In this study, three years (2011-2013) results of measurements of Atmospheric pressure, Temperature, and Relative humidity from Davis Vantage pro2 automatic weather station installed at the ground surface at Lagos (6o 27' N, 5 12' E) Lagos State, were used to examine the effects of meteorological parameters on refractive index using International Telecommunication Union (ITU-R) model. The results show that average hourly variations of refractivity in the dry season is largely as a result of the variations of the wet component (humidity) while the average daily variations of surface radio refractivity in the rainy season is as a result of the variations of the dry (pressure) component of surface radio refractivity. Refractivity reveals seasonal variations with high values in the rainy season and low values in the dry season over the location. The seasonal variation of refractivity of the troposphere is a function of climatic condition while the hourly or diurnal variation of refractivity depends on local meteorology as observed from the results obtained from study location.
Keywords: Refractivity, Temperature, Atmospheric pressure, Relative Humidity