High Resolution Radar Precipitation Evaluation

A series of experiments were undertaken to determine if any operational benefit might be realized from an upgrade of WSR-88D hourly precipitation products to the highest spatial resolution now possible, namely 0.5° x 250 m. The precipitation products are currently disseminated in arrays of 1.0° x 1000 m spacing. Reflectivity from the NCAR S-Pol S-band radar (a radar with similar characteristics to the WSR-88D) in east-central Florida during the summer of 1998 were converted into precipitation estimates and collated with 1-hour gauge accumulations collected from several high-density rain gauge networks that were deployed simultaneously in the region. Radar-gauge correlations were calculated for several degrees of spatial aggregation, ranging from 1.0° x 150 m to 1.0° x 900 m. Correlations were estimated from over 8000 radar-gauge pairs, for both single points and areal averages. It appears that the degree of spatial aggregation of the radar estimates has little effect on radar-gauge correlations.