This physical and biological system of the Bay of Biscay and Western channel is developed at IFREMER (Brest, France) and can provides hourly forecasts. Modeling was performed using the MARS-3D (3D hydrodynamical Model for Applications at Regional Scale) code developed at IFREMER (Lazure et Dumas, 2008). Primitive equations are solved applying the Boussinesq approximation, hydrostatic equilibrium and incompressibility.

Bay of Biscay (8°W) , English Channel and South North Sea (52.7°N)

MARS3D (Lazure and Dumas , 2008)

Hourly

Spherical coordinate (4km at mid latitude)

30 sigma levels

Interpolated from SHOM and Ifremer data basis

- Bulk formula : Luyten(1992)

- 73 rivers from Spain, France, England and Belgium. Daily run off for Adour, Gironde, Loire ,Vilaine, Seine Rhin rivers and some small French rivers when available., otherwise climatological.

- Sea level calculated by a barotropic 2D model of the Western european shelf forced by tides, atmospheric pressure and surface wind stress.

- Baroclinic open boundary condition from Mercator regional model (Fall 2008).

Quadratic bottom friction (Z0 formulation)

Laplacian diffusion

Iso-sigma laplacian diffusion (1m2/s)

TKE vertical mixing model (Gaspar,90)

Schwidersky tidal constituants at the boundaries of the barotropic model

Primary production

The domain has been extended and considers now the entire English Channel and the South North Sea.

The surface atmospheric forcings follows another formulation and a lot of runoffs has been taken into account.

Now this subregional system use the regional PSY2V3 system outputs as baroclinic open boundary conditions and thus the downscaling scheme of the integrated IBIROOS is improved.

The tidal barotropic component at the open boundary has been changed too.