Evaluation of Retrospective and Real-time NGGPS FV3GFS Experiments for Q3FY18 Beta Implementation

NOAA selected the GFDL finite­ volume cubed-sphere dynamical core (FV3) as the Next Generation Global Prediction System (NGGPS) dynamical core. NCEP has implemented the dycore into the NOAA environmental modeling system infrastructure, updated its global data assimilation system to exchange information between the forecast model on cubic-sphere grids and data assimilation on Gaussian lat-lon grids, and developed a new workflow system for both research and operation. A beta version of the FV3 Global Forecast System (GFS) will be set up in Q3FY18 to run semi-operationally alongside with the current operational GFS which has a spectral dynamical core. A final version of the FV3GFS is scheduled to be implemented into operation to replace the global spectral model in Q2FY19. The FV3GFS beta version uses the same physics package as the current operational GFS except for 1) the replacement of Zhao-Carr microphysics with the more advanced GFDL microphysics, 2) an updated parameterization of ozone photochemistry with additional production and loss terms, 3) a newly introduced parameterization of middle atmospheric water vapor photochemistry and, 4) a revised bare soil evaporation scheme. In this presentation we assess the performance of the FV3GFS Beta version based on a one-year retrospective experiment and a real-time forecast experiment. These experiments are fully cycled with data assimilation. Results will be compared with operational numerical prediction models and various observations.