Ruiyu Sun1,2, Jack Kain2, and Jongil Han2,3
1:IMSG/EMC/NCEP,2: EMC/NCEP; 3: SRG/EMC/NCEP
Cloud cover significantly influences the radiation budget of earth‐atmosphere system through regulating both longwave (LW) and shortwave (SW) radiative transfer. It is an important field in both weather and climate forecasts. Many methods including both diagnostic and prognostic methods have been developed to determine the cloud cover. Among the diagnostic methods, some are statistically based, others are empirical. Prognostic cloud cover has advantages over the diagnostic methods in connecting the cloud cover generation and dissipation with physical processes, such as planetary boundary layer turbulence, cumulus convection, and the large‐scale stratiform clouds. In the current operational GFS, the cloud cover is calculated by using a simple statistical cloud cover scheme based on an assumption of uniform distribution of total water. In this study, a prognostic cloud scheme is implemented in the in the GFS. Forecast experiments will be performed. The impacts of the prognostic cloud cover will be examined and analyzed.
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