Analytical formulation of the vertical refractivity profiles associated to evaporation ducts

Ducting is a major phenomenon that affects the radar systems operating above the sea surface. The refractivity profiles derived from bulk models can be approximated by analytical expressions whose precision must be analyzed. We examine here a quite new published expression and show that, in terms of radar propagation, it gives very similar results to those obtained with the complete bulk profiles (The computed propagation factors generally differs by only a few tenths of dB).