A comparative research on the effects of cosmic ray flux on tropospheric refractivity variations and its implication on radio communication in Nigeria wasinvestigated. The atmospheric data (Temperature, Pressure and Relative Humidity) for five locations across Nigeria, Akure (6°57'50.85"N, 4°36'17.19"E), Anyigba,(7⁰45'N, 6⁰45' E),) Nsukka (6°51'28.14"N, 7°24'28.15"E), Port - Harcourt (4⁰ 48'N, 7⁰E) and Yola (9⁰11' N, 12⁰30' E) was acquired from Centre for Atmospheric Research Kogi State while Cosmic rays data was downloaded from Mexico Cosmic ray Observatory. Five years’ data were employed in each case while atmospheric data were used for the computation of tropospheric refractivity. The integration time for the data is in two minutes. Diurnal and seasonal variations of tropospheric refractivity across the five stations were determined to identify zones that have more impact of cosmic rays on radio communication. It was observed that diurnal variations of refractivity in the rainy season was caused by changes in the dry component refractivity while the diurnal changes in dry season was as a result of wet component of refractivity in all the stations except Yola which is in Northern part of Nigeria. There were series of signal fluctuations experienced between the average atmospheric parameters and cosmic ray fluxes. Careful application of correlation test was carried out between the variations of cosmic ray and tropospheric refractivity. The degree of correlation between cosmic ray fluxes and the variation of the average Earth’s atmospheric parameters in each of the stations was found to differ according to the season and zone. The impacts of cosmic rays on radio communication were found in all the stations, although the pattern of its effect differs from one station to the other. The results show that the impact of cosmic rays on radio communication during rainy season is greater than the results in dry season. This is as a result of refractivity variation pattern in both seasons which is driven by variations in meteorological parameters.
