Microwave anomalous propagation (AP) measurement over Akure South-Western Nigeria

Anomalous propagation (Anaprop) of microwave radiation is known to be caused by several meteorological conditions. In this study, radio refractive index and modified refractivity gradient were computed using the results of measurements of atmospheric pressure, temperature and relative humidity made in Akure (7.15°N, 5.12°E), South Western Nigeria using Davis 6162 Wireless Vantage Pro2 weather stations (Integrated Sensor Suite, ISS) positioned at five different height levels beginning from the ground surface and at intervals of 50 m from the ground to a height of 200 m on a tower/mast owned by the Nigeria Television Authority (NTA) located at Iju in Akure north local government area of Ondo state but which is no longer being used. The study utilized one year of data measured between January and December 2008. From the results, the modified refractivity was calculated and found to increase with increasing altitude. The values were observed to be generally high during the rainy periods and generally low during the dry periods. The study also revealed that for microwave propagation in this geographic zone, the propagation condition is mostly super-refractive.