COMPARISON OF GAGE VS MULTI-SENSOR (RADAR plus GAGE)PRECIPITATION ESTIMATES FOR MIDWESTERN UNITED STATESCOUNTIES

摘要

An intercomparison of gage and radar-based precipitation estimates wasundertaken for the Midwestern United States. Multi-sensor precipitation estimates(MPE) based on the Stage III/IV algorithm developed by the Office of Hydrology / NWSRiver Forecast Centers, National Weather Service quality-controlled cooperative gage(QC_Coop) data, and gage data from three high density networks in Illinois fromFebruary 2002 through August 2005 were examined.Most differences in county-averaged monthly precipitation estimated byQC_Coop and MPE in nine Midwestern states were within +/- 25%, averaging 6%. Thedifference between gage and MPE monthly values decreased somewhat through the 41-month period of study. Data from three regional gage networks indicated that on a dailybasis, averaged MPE and gage network data agreed to within about +/- 25%. Daily MPEvalues were often lower than the gage values for large precipitation amounts. Whenexamining multiple gages within single MPE grid points, it was found that for very lowdaily precipitation amounts, MPE grid amounts were generally greater than gage, and forhigh daily precipitation amounts, MPE amounts were lower than gage amounts.