Deep Ocean Modelling - NCOF - The National Centre for Ocean Forecasting


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Deep Ocean Modellingfoam image

Click here for the sample daily updated North Atlantic FOAM Forecast

A global configuration of the Forecasting Ocean Assimilation Model (FOAM) has run daily since October 1997, forecasting 3-dimensional ocean currents, temperature, salinity and sea ice concentration, thickness and velocity. A key feature of FOAM is the assimilation of observational data into physically-based ocean and sea-ice models to ensure an accurate representation of the current ocean state. The model is then forced by 3-hourly forecast winds form the Met Office numerical weather prediction (NWP) system, to forecast how the ocean and ice will evolve over the following seven days.

The FOAM system has recently been transitioned to use a new core ocean model: the Nucleus for European Modelling of the Ocean or NEMO system. The NEMO system has been developed at LOCEAN-IPSL, Paris and has now been adopted as a community model at a number of research and operational centres.

At the same time the operational configurations of the model were upgraded to provide higher horizontal and vertical resolution globally. The following table details the current operational configurations. All configurations have 50 levels in the vertical with a 1m resolution near the surface. The regional versions of FOAM are nested within the global model to provide conditions at their boundaries. The model is relocateable, so new configurations can be nested within the system where required. The Global ORCA025 model has been adapted from the system developed at Mercator Océan, Toulouse.


(Click for example model grid field)
latitude x longitude degrees
Global 1/4 x 1/4, Tripolar, curvilinear grid ("ORCA025")
North Atlantic 1/12 x 1/12 (9 km), Rotated grid, approx 20N - 80N, 90W - 20E
Mediterranean 1/12 x 1/12 (9 km), Standard grid, 30N - 47.5N, 05.5W - 42E
Indian Ocean 1/12 x 1/12 (9 km), Standard grid, 25S - 31N, 33E - 106E

Observations from the previous 2 days are assimilated including:

  • temperature and salinity profiles including data from Argo profiling floats, the TAO/TRITON, PIRATA and RAMA moored arrays as well as XBTs and CTDs
  • sea-surface height data from satellite altimeters Jason-1, Jason-2 and Envisat
  • ship, buoy and satellite sea-surface temperature observations.
  • the EUMETSAT OSI-SAF sea-ice concentration fields

At higher resolutions, the models are able to resolve dynamic features like ocean eddies, fronts and jets.

Further details of model description and validation are presented in the following pages:


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(Last Updated: 17-11-2011)