Use of the vertical reflectivity profile for identification of anomalous propagation

Anomalous propagation (anaprop), analogous to the upper mirage in the visua l wavelengths, is still a major problem in radar meteorology. This phenomen on assumes particular importance in automatic recognition and estimation of rainfall. Anaprop echoes from terrain features such as hills and coasts Of ten give echoes up to 50-60 dBZ equivalent to heavy rain or hail in severe thunderstorms. Anaprop echoes from sea waves may be comparable in strength to those from moderate precipitation and also form similar patterns. Based on the evidence that the vertical reflectivity profile of precipitation is quite different from the anaprop profile, two methods for anaprop identific ation are presented. The method proposed by the Servizio Meteorologico Regi onale (SMR, Italy) simply uses the operational scan procedure to discrimina te between precipitation and anaprop. At the Swedish Meteorological and Hyd rological Institute an 'ad hoc' scan strategy has been developed in order t o obtain much more detail of the lowest reflectivity profile. A number of s tatistical parameters have been used to achieve a better discrimination bet ween precipitation, land and sea clutter. A number of case studies, represe nting different echo intensities and patterns, and including a case of anap rop with embedded precipitation, are presented to assess the impact of thes e methods.