Multi-Watershed Evaluation of WSR-88D (NEXRAD) Radar-Precipitation Products for Hydrologic and Natural Resources Modeling Applications

The National Weather Service (NWS) operates a network of Doppler-radar stations (NEXRAD, WSR-88D) that produce hourly-rainfall estimates, at approximately 4-km² resolution, with nominal coverage of 96% of the conterminous US. Utilization of these data by the NWS are primarily for the detection and modeling of extreme-weather events. Radar-precipitation estimates were compared with gauge estimates at 6 ARS watershed-research locations in Idaho, Arizona, Oklahoma, Georgia and Mississippi, to evaluate the utility of these data for hydrologic and natural resources modeling applications. Radar precipitation estimates underestimated gauge readings for all locations except Tucson. In all cases, the total number of hours with measured-radar precipitation was much less than hours containing gauge-precipitation estimates. Additional modification of NWS precipitation processing procedures will be necessary to improve accessibility and utility of these data for hydrologic and natural resource modeling applications.