It is the product of a mathematical ocean model governed by equations from fluid dynamics, known as “primitive equations” (e.g. NEMO-OPA). These numerical equations are resolved by millions of calculations on super-computers. Observation data are then assimilated in the model, i.e. the results of the mathematical model are combined with observation data (e.g. from satellites or *in-situ* buoys) in order to generate the most realistic possible final representation of the ocean state. This also makes it possible to provide 7-day forecasts of the ocean state. A numerical model therefore enables forecasters to provide a three-dimensional representation, current, past or future, of the ocean’s physical or biogeochemical state.

Both the Mercator Ocean Service and the Copernicus Marine Service offer products generated by numerical models:

Mercator Ocean Service’s reference products are described in the following table.

The products of the Copernicus Marine Service are available here.