An Intercomparison between Mean Areal Precipitation from Gauges and a Multi-Sensor Procedure

This study examines differences between rain gauge precipitation estimates and those from the National Weather Service's (NWS's) Multi-sensor Precipitation Estimator (MPE) which blends hourly gauge data with radar estimates onto a 4 x 4 km grid. Comparisons are made between 1996–2003 on five Florida watersheds. Comparison statistics are found to improve during the period. Differences between MPE- and gauge-derived precipitation depend greatly on gauge density within the basin which generally increases during the study period. Differences between MPE and gauge-derived precipitation are related to the seasons because of the different types of precipitation generally associated with each. Several factors are thought to explain the tendency for smaller MPE than gauge totals with increasing gauge amounts. Differences between MPE and gauge totals are compared for hourly, 6-hourly, and daily accumulations. The agreements improve with increasing periods of accumulation.