Variation of Surface Refractivity with Soil Permittivity and Leaf Wetness in a Tropical Location

Abstract

Radio signal transmitting above the ground surface experiences attenuation as a result of absorption by vegetation and hydrometeors, refraction due to turbulence in weather parameters; and reflection from ground surface. In this study, attempt was made to compute surface refractivity from its constituent parameters, and investigate its variation with leaf wetness and soil permittivity, in seven (7) different stations across Ondo state, Nigeria. Data for the research were obtained by in-situ measurement using Davis weather station Vantage Pro 3125 having sensors for measuring temperature, pressure and relative humidity; 2 leaf wetness sensors and 3 soil moisture content sensors. The soil moisture content was obtained at 30cm soil depth while leaf wetness was measured directly. Correlation of surface refractivity with soil permittivity and leaf wetness ranges between 0.13 and 0.84 across the different stations and seasons. Abstract Radio signal transmitting above the ground surface experiences attenuation as a result of absorption by vegetation and hydrometeors, refraction due to turbu-lence in weather parameters; and reflection from ground surface. In this study, attempt was made to compute surface refractivity from its constituent param-eters, and investigate its variation with leaf wetness and soil permittivity, in seven (7) different stations across Ondo state, Nigeria. Data for the research were obtained by in-situ measurement using Davis weather station Vantage Pro 3125 having sensors for measuring temperature, pressure and relative humidity; 2 leaf wetness sensors and 3 soil moisture content sensors. The soil moisture content was obtained at 30cm soil depth while leaf wetness was measured di-rectly. Correlation of surface refractivity with soil permittivity and leaf wetness ranges between 0.13 and 0.84 across the different stations and seasons.