Integration of radar with analysis fields - Bringing distant radar observations "down to Earth"

Normal refraction of radar waves through the atmosphere prevents radar data at distant ranges from being quantitatively representative for the Earth's surface unless precipitation-related processes taking place between the ra dar echo and the surface are taken into account. A one-dimensional model is presented which uses a physical description of the processes involved in o btaining surface precipitation rate from a radar echo aloft, comprising loc al production, coalescence and evaporation. One or two cloud layers are ass umed depending on the cloud base height. Input data are operationally analy sed cloud base height, temperature, and humidity along with radar observati ons and their altitudes. At the moment, only precipitation as liquid water is assumed in the model. The method and results using it will be presented and discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.