Assimilation of Doppler Radar Radial Wind For High Resolution Forecast initialization at NCEP

Real-time access to WSR-88D level-II radar data has been available at National Centers for Environmental Prediction (NCEP) since May 2005. The NCEP/Environmental Modeling Center (EMC) has developed the capability of assimilating radar radial wind in the NCEP grid-point statistic interpolation (GSI) analysis system. WSR-88D radar radial winds will be analyzed using GSI to initialize NCEP's high resolution forecast with the NMMB model. This experimental NMMB model is run over a CONUS-sized domain with 4-km horizontal grid spacing. All available WSR-88D radar radial winds in the CONUS domain after quality control will be used in the GSI analysis. The bias between observed radial wind and model background will be examined first. The impact of radar wind on the analysis and NMMB forecast will be examined also.