Forecasting the ocean state using NEMO:The new FOAM system

The Forecasting Ocean Assimilation Model (FOAM) deep ocean analysis and forecasting system has been running operationally at the Met Office for over 10 years. The system has recently been transitioned to use the Nucleus for European Modelling of the Ocean (NEMO) community model as its core ocean component. This paper gives an end-to-end description of the FOAM-NEMO operational system and presents some preliminary assessment of operational and hindcast integrations including verification statistics against observations and forecast verification against model best guess fields. Validation of the sea surface height fields is presented, which suggests that the system captures and tracks the major mesoscale features of the ocean circulation reasonably well, with some evidence of improvement in higher-resolution configurations.