Dynamical downscaling precipitation over Southwest Asia: Impacts of radiance data assimilation on the forecasts of the WRF-ARW model

Based on the dynamical downscaling with the Advanced Research Weather (WRF-ARW) mesoscale model, the accuracy of the precipitation forecasts in Southwest Asia has been assessed. Results show that the accuracy of the 24-h and 48-h forecasts for precipitation is closely related to the complex topography of the mountain areas. erstand the impacts of the initial condition uncertainties on accuracy of the dynamical downscaling, a series of data assimilation experiments has been performed. The Advanced Television and Infrared Observation Satellite Operational Vertical Sounder (ATOVS) radiance observations and a data assimilation system named the Gridpoint Statistical Interpolation (GSI), developed by the National Centers for Environmental Prediction (NCEP), were used in this study. The results show that the satellite data provides beneficial information for improving the initial conditions for the dynamical model system and the “forecast” errors are reduced for most locations within the 24-h hindcasts.