setup.rst

Setting up a new configuration

• Starting from an existing configuration
  • Option 1: Duplicate an existing configuration
  • Option 2: Duplicate with differences
  • Option 3: Use the SIREN tools to subset an existing model
  • Option 4: Use the nesting tools to create embedded zooms or regional configurations from an existing grid
• Creating a completely new configuration
  • Option 1: Create and use a domain configuration file
  • Option 2: Adapt the usr_def configuration module of NEMO for you own purposes

Starting from an existing configuration

There are three options to build a new configuration from an existing one.

Option 1: Duplicate an existing configuration

The NEMO so-called Reference Configurations cover a number of major features for NEMO setup (global, regional, 1D, using embedded zoom with AGRIF...)

One can create a new configuration by duplicating one of the reference configurations (ORCA2_ICE_PISCES in the following example)

$ ./makenemo –n 'ORCA2_ICE_PISCES_MINE' -r 'ORCA2_ICE_PISCES' -m 'my_arch'

Option 2: Duplicate with differences

Create and compile a new configuration based on a reference configuration (ORCA2_ICE_PISCES in the following example) but with different pre-processor options. For this either add add_key or del_key keys as required; e.g.

$ ./makenemo –n 'ORCA2_ICE_PISCES_MINE' -r 'ORCA2_ICE_PISCES' -m 'my_arch' del_key 'key_xios' add_key 'key_diahth'

Option 3: Use the SIREN tools to subset an existing model

Define a regional configuration which is a {sub,super}-set of an existing configuration.

This last option employs the SIREN software tools that are included in the standard distribution. The software is written in Fortran 95 and available in the :file:`./tools/SIREN` directory. SIREN allows you to create your own regional configuration embedded in a wider one.

SIREN is a set of programs to create all the input files you need to run a NEMO regional configuration.

Demo:	Set of GLORYS files (GLObal ReanalYSis on the ORCA025 grid), as well as examples of namelists are available here.
Doc:	:forge:`chrome/site/doc/SIREN/html/index.html`
Support:	Any questions or comments regarding the use of SIREN should be posted in :forge:`the corresponding forum <discussion/forum/2>`.

Option 4: Use the nesting tools to create embedded zooms or regional configurations from an existing grid

(see :coderepo:`NESTING README </tools/NESTING/README>`).

Creating a completely new configuration

From NEMO version 4.0 there are two ways to build configurations from scratch. The appropriate method to use depends largely on the target configuration. Method 1 is for more complex/realistic global or regional configurations and method 2 is intended for simpler, idealised configurations whose domains and characteristics can be described in simple geometries and formulae.

Option 1: Create and use a domain configuration file

This method is used by each of the reference configurations, so that downloading their input files linked to their description can help. Although starting from scratch, it is advisable to create the directory structure to house your new configuration by duplicating the closest reference configuration to your target application. For example, if your application requires both ocean ice and passive tracers, then use the ORCA2_ICE_PISCES as template, and execute following command to build your MY_NEW_CONFIG configuration:

$ ./makenemo –n 'MY_NEW_CONFIG' -r 'ORCA2_ICE_PISCES' -m 'my_arch'