13.4. Grids

13.4.1. OASIS grid files

OASIS manage grids and interpolations by using dedicated grid files:

  • grids.nc

  • masks.nc

  • areas.nc (requested only for some of the interpolation types)

These files can be automatically created by OASIS functions called in each model, or can be created by the user in advance if specificities are requested. Some facilities are provided in croco_tools/Coupling_tools to create such grids.

If grids.nc, masks.nc, areas.nc exist in the working directory, they won’t be overwritten by OASIS functions. So, be sure to have the good files or remove them before running the coupled model.

13.4.2. Multiple model grids (nesting case)

Multiple nested grids in the different models can be used in coupled mode.

The variables are therefore exchanged from/to the different grids. To do so, each coupled variable is identified in the coupler with its grid number:

  • For CROCO the last character of the OASIS variable name defines the domain

    • 0 being the parent domain

    • 1 the first child domain, etc.

  • For WRF the domains are defined by d01, d02, etc, and the target domain (CROCO for instance), by EXT_d01, EXT_d02, etc.

For example if you are coupling 2 CROCO domains to one atmospheric domain, you will specify 2 types of exchanges in the namcouple:

# exchange between CROCO parent domain to WRF domain

# exchange between CROCO child domain to WRF domain

If you are coupling 2 WRF domains to one CROCO domain:

# exchange between WRF d01 domain to CROCO domain

# exchange between WRF d02 domain to CROCO domain