Verification and error analysis of quantitative precipitation estimation and forecast products in SWAN

Based on the precipitation data from intensive regional automatic weather stations and data from 6 new generation weather radars in Henan from May to September during 2010-2011, error distribution of the Quantitative Precipitation Estimation (QPE) and Quantitative Precipitation Forecast (QPF) from SWAN in severe short-range precipitation in Henan are analyzed by point to point statistical test methods, and then the differences between QPE and QPF in the regional and local precipitation processes and direct cause to produce error are discussed. The results show the following. (1) Both QPE and QPF perform well for rainfall less than 10 mm·h-1. QPE performs best in south-western and northern Henan, while QPF performs best in central Henan. The estimation of QPE is typically greater than the observation. QPF is slightly larger than the observation when the hourly rainfall is less than 20 mm, but it is less than the observation for heavier precipitation,especially in western and southern Henan. (2) Both QPE and QPF perform better in regional precipitation than in local precipitation. (3) In regional precipitation, QPE performs well in estimation of both the range and location of the precipitation center, and the estimation of QPE is slightly greater than the observation. QPF shows a slight deviation to predict the position of precipitation center and shows a smaller central intensity than observation.