The Copernicus Marine Service global ocean analysis and forecasting 1/12° high-resolution system. Recent changes and future evolution.

Since November 2022, and within the framework of the Copernicus Marine Service, Mercator Ocean International has been delivering real-time daily services (weekly analyses and daily 10-day forecasts) with a major release of the global 1/12° high-resolution (eddy-resolving) GLO12 analysis and forecasting system. Ocean observations are assimilated into the model using a reduced-order Kalman filter method (SEEK). Along-track altimeter sea level anomaly, satellite sea surface temperature and sea ice concentration, as well as in situ temperature and salinity vertical profiles, are jointly assimilated to estimate the initial conditions for numerical ocean forecasting. A 3D-VAR scheme is also used to better control slowly evolving large-scale biases in temperature and salinity.

Some interactions with the Hydrography and Oceanography Service of the French Navy have helped to identify several issues, and actions have therefore been taken to resolve the identified problems and further improve the system’s behaviour.

Moreover, the GLO12 system will benefit from several developments throughout 2026, such as the introduction of wave forcing to improve dynamics and system behaviour in the mixed layer depth, daily analyses to improve forecast quality, and the assimilation of SWOT wide-swath observations to improve, in particular, ocean currents and fronts. All these activities have already started in R&D mode and have already produced promising results.

This presentation will describe the components of the system that have been revisited and will show how some identified weaknesses in the system have been, or will be, improved.