Statistics of lower atmosphere refractivity in Czechia

Atmospheric refractivity influences significantly the propagation of electromagnetic waves in atmosphere. ITU-R recommends using statistics of a refractivity vertical gradient in the lowest 65 meters above the ground for estimation of multipath fading incidence on the terrestrial fixed wireless links. In this paper, results of the measurement of atmospheric refractivity in a lower 80 m layer of atmosphere are presented. Daily and monthly variability of refractivity and of its vertical gradient is shown. Refractivity statistics are compared with the quantiles obtained from the ITU-R world map.