RADAR RAIN FIELD-EVALUATION AND POSSIBLE USE OF ITS HIGH TEMPORAL ANDSPATIAL-RESOLUTION FOR HYDROLOGICAL PURPOSES

The purpose of this paper is to show how accurate radar-estimated rain fall, with good temporal and spatial resolution, can be used for hydro logical purposes. A recent methodological advance in rainfall measurem ent using conventional weather radars has made it possible to account for much of the variation between the precipitation radar echo intensi ty and rain intensity. A method known as the window probability matchi ng method (WPMM) was applied to radar measurements over several catchm ent areas in central Israel. Comparison of daily raingauge measurement s with radar rainfall estimates demonstrated good agreement. The stand ard error of radar-estimated rainfall was only 7% for a storm with a t otal average accumulation of 328 mm. Several case studies are provided which demonstrate the advantage of having an accurate rain field for calculating excess rainfall for each of the area grid squares in the w atershed. Storm excess rainfall for different time durations depends s trongly not only on the area size, but also on the differences in the rainfall intensity sequences. Accurate radar rain fields can permit dy namic calculations to be made along the storm path.