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NEMO Reference Configuration

This section details the reference configuration of the NEMO model as integrated within the SURF-NEMO package. It covers both predefined model parameters and specific customizations made to the NEMO source code.

Reference Configuration for NEMO

Although users can customize many aspects of their ocean simulation (as detailed in Section User Configuration), several NEMO input parameters are fixed in SURF-NEMO. These predefined settings are stored in the setParFix.ncl file, located at /surf_nemo/scripts/preproc/setVarFileName/setParFix.ncl within the SURF-NEMO package.

Below is an overview of the most relevant fixed model parameters:

  • Tracer Advection Scheme:
    The Monotonic Upstream Scheme for Conservation Laws (MUSCL) was used for tracer advection. This scheme provides high accuracy while maintaining monotonicity in the numerical solutions, preventing spurious oscillations.
  • Momentum Advection Scheme:
    The Energy and Enstrophy Conservative (EEN) scheme was applied for momentum advection. This method, as described by Arakawa and Lamb (1981) and Barnier et al. (2006), conserves both energy and enstrophy, ensuring a physically realistic representation of momentum transport.
  • Lateral Boundary Conditions:
    No-slip conditions were implemented on all closed lateral boundaries, ensuring that there is no unrealistic velocity at the boundaries of the computational domain.
  • Bottom Friction:
    A quadratic friction formulation is used to parameterize bottom friction, accurately simulates frictional forces at the ocean floor.

For a comprehensive list of all predefined parameters, please consult the setParFix.ncl file directly.

NEMO Source Code Customization

The NEMO model version integrated into SURF-NEMO is v3.6 (stable release).

SURF-NEMO includes specific modifications to the NEMO source code to support flexible model initialization. The following source files have been modified:

  • istate.F90, tdasshd.F90, and dtauvd.F90: Enable initialization of all key prognostic variables (temperature, salinity, zonal/meridional velocities, and sea surface height) via user-defined fields. This functionality is controlled using two custom namelist sections: &namuvd and &namsshd.

These customizations are particularly beneficial for short-term simulations, as they can reduce the model's spin-up period.