OASIS3 can be used in an interpolator-only mode, in which case it transforms fields without running any model. It is recommended to use first OASIS3 in this mode to test different transformations and interpolations without having to run the whole coupled system. In the interpolator-only mode, all transformations, except the time transformations, are available.
To run OASIS3 in an interpolator-only mode, the user has to prepare the namcouple as indicated in sections 5.2 and 5.3. In particular, NONE has to be chosen below the keyword $CHANNEL; ``0'' (without any model name and Fortran unit number) must be given below the keyword $NBMODEL; $RUNTIME has to be the number of time occurrences of the field to interpolate from the NetCDF input file; finally, the ``coupling'' period of the field (4th entry on the field first line) must be always ``1''. Note that if $RUNTIME is smaller than the total number of time ocurrences in the input file, the first $RUNTIME occurrences will be interpolated.
The name of the input file which contains the fields to interpolate is given by the 6th entry on the field first line (see 5.3). After their transformation, OASIS3 writes them to their output file which name is the 7th entry on the first line. Note that all fields have to be present in the same restart file.
The time variable in the input file, if any, is recognized by the its attribute "units". The acceptable units for time are listed in the udunits.dat file (3). This follows the CF convention. A practical example on how to use OASIS3 in a interpolator-only mode is given in prism/util/running/toymodel/testinterp (from CERFACS CVS only).
The configuring parameters that have to be defined in the namcouple for each transformation in the interpolator-only mode or in the coupling mode are described here after.