Differences in multi-sensor and rain-gauge precipitation amounts

Abstract

A comparison of multi-sensor (radar and gauge) and gauge precipitation estimates at a monthly temporal resolution and a county spatial resolution was undertaken for the midwestern USA. Precipitation data were collected from February 2002 to October 2006 from two sources: (a) multi-sensor precipitation estimates (MPE) based on the stage III/IV algorithm developed by the US National Oceanic and Atmospheric Administration (NOAA), national weather service (NWS) office of hydrology and NWS river forecast centres; and (b) quality-controlled NWS cooperative rain-gauge (QC_Coop) data from the NOAA national climatic data centre (NCDC). The gauge data were employed as the reference standard. The monthly median of the percentage differences in county-averaged monthly precipitation estimated by MPE and QC_Coop in the midwestern USA, for around 750 counties, was mainly within ±12·5%, with a median percentage difference of +6%. The positive difference indicates that, overall, the MPE values tend to be smaller than the QC_Coop values. ME values more closely correspond with QC_Coop values at all latitudes in the summer months when convective precipitation is dominant, and in the winter months for latitudes where non-frozen precipitation is most prevalent.