Assimilation of All-sky Microwave Radiances in the NCEP's Global Forecast System

Currently only clear-sky radiances are assimilated operationally in the NCEP's hybrid 3DVAR/Ensemble Global Forecast System (GFS), and development efforts have been actively engaged in the all-sky radiance data assimilation. This study is focused on non-precipitating cloudy AMSU-A radiances. With the recently upgraded GFS, the issues of using different cloud control variables, bias correction, cloud generation and elimination, and background error covariance obtained through static covariance and the ensemble as well as multi-variable balance are discussed and tested in this study. Future plans will also be presented at the conference.