Spatial-temporal analysis of inter tropical discontinuity influence on radio signal behavior in Nigeria

This study investigates the influence of the inter tropical discontinuity (ITD) on radio signal behavior over Nigeria using ERA5 data from the Copernicus Climate Change Services (C3S). Monthly variations of refractivity gradient values and ITD movements were analyzed through spatial distribution and wavelet coherence. Results indicate that the ITD position significantly affects refractivity gradient values. Below the ITD, values range from − 5 to −110 N-units/km, while above the ITD, values are less than −110 N-units/km, indicating predominant ducting conditions. The ITD shifts latitudinally from a peak at 20° in August to a low at 5° in December. Correlation coefficients between ITD position and refractivity gradient values in different climatic regions (Am, Aw, BSh, BWh) range from −0.920 to 0.844, emphasizing the significant influence of ITD on atmospheric conditions in these regions. Statistical analysis using the wavelet coherence method demonstrates a strong connection between ITD and refractivity gradient, with coherence values indicating synchronization at specific frequency-time pairs.