Retrieving evaporation duct heights from measured propagation factors

The knowledge of refractivity is very important for coverage prediction. This problem is common above sea, where the particular atmospheric conditions lead to atmospheric ducts which strongly modify the range of the radar compared to the standard atmosphere coverage. The most common duct which is almost always present is the evaporation duct. The aim of this paper is to present two inversion methods to retrieve the evaporation duct height from the propagation factor measured along the propagation path during the Vampira campaign 2004. The two inversion methods considered are the simple quadratic regression and the least-squares support vector machine.