2 Coupling restart files

At the beginning of a coupled run, some coupling fields may have to be initially read from their coupling restart file on their source grid (see the LAG concept in section 2.5.3). When needed, these files are also automatically updated by the last active oasis_put or prism_put_proto call of the run (see section 2.2.7) . Warning: the date is not written or read to/from the restart file; therefore, the user has to make sure that the appropriate coupling restart file is present in the working directory. The coupling restart files must follow the NetCDF format.

The name of the coupling restart file is given by the 6th character string on the first configuring line for each field in the namcouple (see section 3.3). Coupling fields coming from different models cannot be in the same coupling restart files, but for each model, there can be an arbitrary number of fields written in one coupling restart file. One exception is when a coupling field sent by a source component model is associated with more than one target field and model; in that case, if coupling restart files are required, it is mandatory to specify different files for the different fields.

The coupling restart files are also used automatically by OASIS3-MCT to allow partial LOCTRANS time transformation to be saved at the end of a run for exact restart at the start of the next run. When LOCTRANS transformations are specified, the initial coupling restart file should not contain any LOCTRANS restart fields. For the following runs, it is mandatory that the coupling restart file contains LOCTRANS restart fields coherent with the current namcouple entries. For example, it will not be possible to restart a run with a multiple field entry in the namcouple with a coupling restart file created by a run not activating this multiple file option.

In the coupling restart files, the fields must be provided on the source grid in single or double precision REAL arrays and, as the grid data files, must be dimensioned (nx, ny), where nx and ny are the grid first and second dimension (see section 5.1 above). The shape and orientation of each restart field (and of the corresponding coupling fields exchanged during the simulation) must be coherent with the shape of its grid data arrays.