Deduction of the Radio Wave Propagation Condition at Low Altitude from Self-measured Meteorological Data for Ekpoma Area, Nigeria

Abstract

Refractivity indices (RI) such as the surface refractivity (SR), the refractivity gradient (RG), and the effective earth radius factor (k-factor) are valuable components for predicting the local radio wave propagation (LRWP) conditions in the troposphere. Hence, in this study, the estimation and analysis of the RI (SR, the RG, and k-factor) from the measured m weather/meteorological variables (WV); air temperature (T) , relative humidity (RH), and atmospheric pressure which was reduced to mean sea level pressure (MSLP) in the Ekpoma area of Edo State, Nigeria, which is located within Latitude 6.74° N and Longitude 6.14° E for a period of twelve months (January to December, 2022), so as to infer the radio propagation conditions using a self-designed weather/meteorological monitoring device (WMD), were investigated. The WMD was positioned at a low altitude (height level) of 50 m above sea level at a low-rise building located within the area so as to measure the needed WV. The results show that the SR and the k-factor values were generally higher during the months with high RH (rainy periods) compared to those of the months with lower relative humidity (dry periods), while the RG, values were higher in the dry periods compared to the rainy periods. The average values of the RI for the period under consideration are 355.58 N-units, -61.58 N-units/km, and 1.51 for the SR, the RG, and k-factor respectively. Thus, it is inferentially concluded that the LRWP condition for the Ekpoma is mostly super-refractive.