A Feasibility Assessment of MOM6-CICE6 in the Unified Forecast System as a Future Operational System at NOAA/NWS/NCEP/EMC

NOAA’s National Centers for Environmental Prediction (NCEP) has been implementing the Unified Forecast System (UFS) in an effort to develop the Next Generation Global Prediction System (NGGPS) with extended coupled modeling capabilities for the next generation weather, subseasonal and seasonal prediction. At the Environmental Modeling Center (EMC), the UFS weather model has been configured for a wide variety of applications with Finite-Volume Cubed-Sphere Dynamical Core (FV3), Modular Ocean Model version 6 (MOM6) and the Los Alamos sea ice model version 6 (CICE6) as its atmospheric, oceanic and ice modeling components, respectively. In the present study, authors assess feasibility of the ocean-ice coupled systems (DATM-MOM6-CICE6) of the UFS Weather Model as a future operational system that can replace ocean-ice modeling components (HYCOM-CICE4) of NCEP’s current global operational Real Time Ocean Forecast System (RTOFS). To meet the requirements of weather scale applications, both ocean and ice modeling components are optimized for high resolution (1/12th degree) with a series of parameter tuning experiments in collaboration with EMC’s external partners. Results focus on comparisons of the two systems (UFS-Weather-Model vs. RTOFS-HYCOM) with respect to features and separation locations of boundary currents (e.g., Gulf Stream, Kuroshio Extension); surface eddy shedding intensities of the Loop Current in the Gulf of Mexico; depths of the Atlantic Meridional Ocean Circulation (AMOC); and ice extent and thickness in both polar systems.