Introduction of a Finite-Volume Cubed-Sphere Global Forecast System (FV3GFS) in the NOAA Global OSSE System—Result Comparisons to 3DEnVar GFS

Both Observing System Experiments (OSEs) and Observing System Simulation Experiments (OSSEs) face questions as to whether the impacts shown using the forecast system in the experiments can be recreated in future operational systems. As the National Oceanic and Atmospheric Administration (NOAA) has transitioned to the Finite-Volume Cubed Sphere Global Forecast System (FV3GFS), some of these questions can be addressed in both OSE and OSSE settings. Initial comparisons of OSE/OSSE predictability using the NOAA global OSSE system found that the predictability of real-world and simulated observations in FV3GFS was comparable, whereas simulated observations yielded higher forecast skill than real-world observations in the previous 3DEnVar system. An experiment recreating previously-discussed projects assimilating a constellation of geostationary hyperspectral infrared sounders (GeoHSS) in the global FV3GFS OSSE system will be compared to previous runs using 3DEnVar GFS. Lessons learned from this comparison will be used as part of future OSSE work involving new simulated satellite radiance observation sources.