Last decade, satellite radiance assimilation has been operationally implemented at most leading NWP centers and has proved to be a main factor for the improvement of global weather prediction. However, satellite radiance assimilation applications on regional and mesoscale model has been under-explored. Partial reason for this is that radiance assimilation is mostly implemented in operational centers, and there is no available radiance assimilation system for general research community to stimulate radiance assimilation in mesoscale applications.

Weather and Research Forecast (WRF) model as well as it variational assimilation sytstem (WRF-Var) is widely used by both research community and the operational NWP centers in US (the US Air Force Weather Agency) as well as a number of international WRF partners in Asia, the Middle East, and Europe. A satellite radiance assimilation capability has been developed in the WRF-Var sysem. The WRF-Var radiance assimilation capability was designed for meeting requirements of both basic research and operational applications, which will be available to research community with the next WRF release.

This presentation will begin with a brief overview of radiance assimilation capabilities in WRF-Var, including the core component -- Fast Radiative Transfer Model (RTM), BUFRF radiance data interface, air-mass dependent bias correction algorithm, quality control and observation error tuning and so on. Mention that two widely used RTMs, RTTOV developed by EUMETSAT in Europe and CRTM developed by JCSDA in USA, are incorporated into WRF-Var system. Ability to choose different RTM and other flexibilities will be preferred for diverse applications. Recent results on assimilating microwave radiance data to improve Hurricanes track will be also presented with focus on a few cases from 2005 Hurricane season.