Assimilation of Doppler Radar Observations 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 data. The radial wind is directly analyzed by the NCEP grid-point statistic interpolation (GSI) analysis system. The cloud analysis package developed by Global Systems Division (GSD) is modified and used to analyze reflectivity with NCEP's forecast model background. WSR-88D radar radial winds together with reflectivity are used to initialize NCEP's high resolution forecast with the Nonhydrostatic Multiscale Model on B-grid (NMMB). This experimental NMMB model is run over a CONUS-sized domain with 4-km horizontal grid spacing. Radar data are assimilated for 6 hours with hourly time interval. The impact of radar wind and reflectivity on the analysis and NMMB forecast will be examined.