Statistical study of the dependence of tropospheric refractive index on different weather vagaries

The ITU-R semi-empirical model for the determination of tropospheric refractivity showed that Pressure, Temperature and Humidity are the major determinant of the tropospheric refractive index. This is because research has shown that the contribution of dipole moment to refractive index variation in the troposphere is negligible. The contribution of any of these three weather vagaries to tropospheric refractivity variation depend on location and season. In this study, the actual dependence of the refractive index on each of these vagaries was studied using four years meteorological data (2007-2011) obtained over Nsukka, latitude 6°51´ N, longitude 7°21´ E and 100m above sea level. Statistical analysis of the diurnal variation over rainy and dry season showed that tropospheric refractive index has a distinct dependence on each of the weather vagaries in dry season than the rainy season.