Radar Reflectivity and Attenuation of Radio Waves in the Melting Layer of Precipitation

摘要

The melting layer in precipitation is physically modeled and compared with high resolution Doppler radar data. The model includes a new formulation of the dielectric properties and can handle all ice particles with densities ranging between pure snow and hail. The air temperature is calculated from the vertical air velocity. The model can handle aggregation, breakup and collapse of the melting particles. The results of the model are in good agreement with the Doppler radar observations. The model shows that the reflectivity and attenuation are very sensitive to the dielectric properties and density of the melting particles, and that the influence of aggregation and collapse is restricted. Simple relations between the attenuation and the rain intensity and maximum reflectivity are derived from a statistical analysis.