Spatiotemporal trends and seasonal variations in meteorological parameters and radio refractivity across Nigeria’s eco-climatic zones

Abstract

The propagation of radio waves/signals is strongly influenced by atmospheric parameters, leading to signal degradation, unpredictable communication ranges, and link blackouts; however, this understanding has not been fully explored across diverse eco-climatic zones. Using meteorological data from selected locations across Nigeria’s eco-climatic zones from 1981 to 2022, this study assesses the impact of temperature, relative humidity, atmospheric pressure, and precipitation on radio refractivity at annual and seasonal timescales (dry, onset, wet, and cessation periods). For the annual trend analysis, the Mann-Kendall trend test showed a noticeable increase in variability in both temperature and relative humidity. These trends were further supported by innovative trend analysis, which revealed a steady increase in refractivity, especially in humid climates like Yenagoa and Ibadan. For the analysis across seasons, positive refractivity deviations were largest and most consistent in both the wet and cessation periods, which mainly occurred over the humid and coastal areas (0.13 to 0.15 N-units/year), but weaker or negative trends were observed in the dry and onset periods in the Sahel and Sudan savannah (northern) locations (-0.236 to 0.224 N-units/year). Correlation analysis revealed strong relationships between refractivity and humidity, especially at Sahel and Sudan savannah sites ( r > 0.90). The multilinear regression-based sensitivity framework indicated that relative humidity exerted a greater influence on the refractivity in these climates than in the Mangrove and Freshwater zones; the reverse was identified for temperature. These findings have significant implications for Nigeria’s telecommunications industry and other tropical regions with comparable climatic characteristics, particularly for optimizing network planning and mitigating signal degradation caused by weather fluctuations.