CoAuthors

Mathieu Hamon (Mercator Ocean International, France); Mounir Benkiran (Mercator Ocean International, France)

Ocean analysis and forecasts produced in real time by Mercator Ocean serve a wide range of applications, from marine safety to seasonal forecasts. The global 1/12° ocean forecasting system is operated in the framework of the Copernicus Marine Environment and Monitoring Service. The forecast accuracy is highly dependent on the availability and quality of in situ and satellite observations that are assimilated to constrain the ocean forecast. Along track altimetry data are key observations for those systems as they provide integrated information on the water column, with a regular and global coverage.
Dedicated experiments highlight the sensitivity of the global ocean analysis and forecasts to changes in the altimetry constellation and to the MDT used as a reference to assimilate SLA. Those impact experiments also give an insight on the data assimilation efficiency to ensure the best use of those observations.
The concept of wide swath altimetry is now emerging. Efforts are ongoing on adapting the system to ingest such data and estimate their ability to better constrain the ocean circulation than today with a nadir altimeter constellation. Next challenges, from the assimilation point of view, are now to take into account complex correlated errors within the swath, and control physical processes that are unconstrained today.