Tropospheric Propagation Mechanisms Influencing Multipath Fading Based on Local Measurements

Knowledge of the refractivity index in the lower atmosphere is very important in the design, transmission and performance analysis of line-of-sight (LOS) terrestrial links. In oceanic environments, radio wave propagation is affected by the high variability with space and time of the meteorological parameters. Radiosonde data have been used in the analysis of the effect of climatic conditions in the coastal regions of South Africa and there influence in estimating the occurrence of multipath fading in LOS links. The values of temperature, pressure and relative humidity in the lower atmosphere have been used to compute refractivity and refractivity gradients. The percentage of occurrences of super refractivity and ducting conditions which influence the occurrence of multipath fading are determined from the estimated refractivity gradients. Index Terms Tropospheric propagation, refractivity gradient, multipath fading, radiosonde, coastal regions.