Use of radar observation in hydrological and NWP models : radar techniques for identifying precipitation type and estimating quantity of precipitation

Weather radars provide a prompt overview of falling precipitation over large areas and are therefore of great interest to the hydrological community. The COST Action 717 "Use of radar observation in hydrological and NWP models" considerably facilitated communication among experts of radar meteorology, numerical weather prediction (NWP) and hydrology. The working Group 1 (WG1) of COST Action 717 dealt with the use of weather radar in hydrological modelling and one of its tasks was to set up a summary of the current methods for radar-based quantitative precipitation estimation (QPE). This review, compiled by the WG1 members, provides a summary of radar-based QPE methods along with a modern view on the drop size distribution (DSD) issue and its role in the conversion of radar reflectivity into rain rate.