CHARACTERIZATION OF REFRACTIVE INDEX STRUCTURE CONSTANT ( 2nC ) PROFILE IN SOME SELECTED STATIONS IN NIGERIA.

Abstract

This work describes the analysis of the characterization of refractive index structure constant ( 2 n C ) in some selected stations in Nigeria. The study utilizes 5 years (January 2010-December 2014) meteorological data of air temperature, relative humidity at 1000 hPa, 900 hPa, 800 hPa and 700 hPa atmospheric pressure level retrieved from Era-Interim Reanalysis Platform. The data were obtained daily at 0.750 grid resolution to compute the refractive index structure constant using Tatarskii equation from the potential refractive index gradient for each of the locations: Kano (13°N, 4.4°E), Minna (9.62°N, 6.53°E), Port-Harcourt (4.8°N, 6.98°E), Lagos (6.58°N, 3.33°E) and Akure (7.15°N, 5.12°E). The computed refractive index structure constant was then characterized over all the locations on seasonal and annual basis and its profile was obtained for all the locations over the same periods. The results indicate that refractive index structure constant, 2 n C values are generally high during the wet seasons as compared with the dry season. The result also shows that refractive index structure constant 2 n C decreases with increasing altitudes and increases with increase in atmospheric pressure indicating that turbulence effect is very strong at higher pressures, ground surface and relatively weak at high altitudes. On the average, the refractive index structure constant 2 n C value obtained for the 5 year period of this study for Akure, Lagos, Port-Harcourt, Minna and Kano are: 1.6130 321510m , 3215105513.1m , 3215107256.1m , 3215102929.1m and 3216109823.8m respectively. These results can be classified under neutral and stable atmosphere indicating a stable airflow thereby enhancing radio signal performance when transmitted or received since there will be no scintillation of optical intensity, enlargement and wandering of optical beam, wave front distortion and scattering which often occur when signal are propagated through a turbulent atmosphere.