NEMSfv3gfs: Adopting FV3 to NCEP NEMS System

The GFDL finite volume cubed-sphere dynamical core (FV3) was selected as the dynamic core of the the Next Generation Global Prediction System (NGGPS). The GFDL NGGPS FV3 forecast system with GFS physics package was adopted and implemented into the NOAA Environmental Modeling System (NEMS) infrastructure. The new system was built as a foundation of the Unified Forecast System (UFS).

In this presentation, the implementation work of standalone forecast system NEMSFV3gfs using FV3 dynamic core is presented. The capability of FV3 CAP as the atmosphere grid component interface to the NUOPC model framework is shown in both standalone model and several FV3 based coupled systems. The FV3 atmospheric forecast grid component with FV3 dynamics, IPD and GFS physics is set up. The model outputs and downstream related processes are implemented as write grid component. The performance of this asynchronous IO method is compared to the IO system in original GFDL FV3. The write grid component enables new capabilities such as regridding output fields from native cubed sphere grid to other grids such as Gaussian grid and lat/lon grid on both global and regional domain. The results are presented from those new features too. Besides this, a different compile and build system is set up, a regression test system is developed for continuous integration of internal and external development and the code has been ported to several operational and NOAA research development computers.