Assessment of Simulated Ocean and Sea Ice Characteristics in the Arctic Ocean from a UFS-Based Coupled Ocean-Ice Modeling System

Within the Unified Forecast System – Research to Operations (UFS-R2O) project, UFS-based applications have been developed for transitioning into the National Ocean and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP)’s operational modeling suite. As part of the UFS-R2O project, a new application of the UFS for global ocean-ice predictions is developed. The system is based on the Geophysical Fluid Dynamics Laboratory (GFDL)’s Modular Ocean Model version 6 (MOM6) coupled via NUOPC coupler with the Los Alamos sea ice model version 6 (CICE6). The modeling system uses a tri-polar computational grid with a nominal resolution of 0.08-degree. The long-term objective is to use this modeling system for the real-time operational forecasts superseding the Real-Time Operational Forecast System (RTOFS) presently employed by the NOAA Central Operations for the ocean and sea ice operational forecasts. The MOM6-CICE6 system undergoes performance testing both with data assimilation and in a free running mode. As part of these test simulations, a suit of free-running hindcasts have been performed for the period 2020–2021 to evaluate performance of the MOM6-CICE6. The experiments are initialized from the Navy Global Ocean Forecast System (GOFS3.1). Results from the hindcast simulations of the MOM6-CICE6 are presented to demonstrate how the modeling system represents mesoscale ocean and ice dynamics in the Arctic Ocean and subpolar basins. The model performance is assessed by evaluating ocean and sea ice circulation, representation of the water masses and sea ice characteristics, and oceanic fluxes through Arctic Ocean gateways. The hindcast solutions are compared against RTOFS and other models (global and regional) of similar resolution as well as observations.