Synergic analysis of radio ducting anomalies and atmospheric aerosols' concentration over Nigeria

Abstract

The study investigates the influence of the three atmospheric aerosols viz dust particles (DST), ammonium nitrate (NH4NO3), and sulphate (SO4) on the radio ducting anomalous propagation over thirteen selected locations and their respective regions in Nigeria. Radio duct was computed from temperature, relative humidity, and pressure datasets obtained from the ERA5 database of the European Centre for Medium-Range Weather Forecasts (ECMWF). Also, dust, ammonium nitrate (NH4NO3), and sulphate (SO4) aerosol emissions were obtained from the Representative Concentration Pathway (RCP) 8.5 scenario database of the Integrated Assessment and Climate Modelling community. The data covered a period of seven years (2010 - 2016) across sixteen locations in Nigeria. The seasonal analysis of the ducting frequency of occurrence and that of mass concentration of the aerosols were performed. Beta weight analysis was carried out between atmospheric duct and aerosols. Analyses showed that ducting occurrences were relatively higher when the concentration of dust and SO4 aerosols were very low. Whereas there was no or low occurrence of ducting in the months with a high concentration of dust, SO4, and NH4NO3 aerosols across studied locations. It can be concluded based on correlation analysis that aerosols have a greater influence on the atmospheric duct in the Coastal regions, followed by the Sahel region and then the Savannah region.