Modeling of atmospheric primary radioclimatic variables in Nigeria for microwave radio propagation applications

Abstract

As modern technology advances, more of the radio communication systems are adopting microwave and millimeter waves’ spectral. However, the effects of meteorological parameters over the radio communication signal operating at microwave and millimeter waves have been the concern of radio engineers. Determination of radio refractivity requires as input meteorological parameters such as temperature, humidity, and atmospheric pressure. To assess the level of degradation due to atmospheric parameters, the ability to easily measure these meteorological parameters is important in planning a good quality radio communication networks. In this study, five (5) years (2013–2017) satellite-based meteorological parameters comprising air temperature, relative humidity, and pressure were obtained from the European Center for Medium-Range Weather Forecast (ECMWF) at four synopsis hours of the day (00:00 LT, 00:06 LT, 12 noon LT, and 18:00 LT) on daily basis to model the required radio climatic variables in Nigeria. The data were obtained for 26 locations based on the four climatic regions in Nigeria. Multiple regression analysis of the data was performed and coefficients (bo, b1, …, b6) were obtained to effectively predict the monthly temperature, pressure, and relative humidity at the surface level. Eight stations were used for validation; two each from the four climatic regions of Nigeria based on the coefficient of determination (R2), mean absolute error (MAE), and root mean square error (RMSE). The meteorological parameters were compared based on the multiple regression analysis (MRA) and the modified interpolation techniques (Kriging and Inverse Distance-IDW). The three methods show nearly good accuracy in the prediction, however, the MRA was found to have a better prediction for the meteorological parameter in Nigeria. Hence, in predicting the refractive index parameters using MRA, the allowed RMSEs for temperature, pressure, and relative humidity are 0.559, 4.693, and 0.267, respectively. Likewise, the allowed MAEs for temperature pressure and relative humidity are 0.492, 0.229, and 3.837, respectively.