The data ocean model requires two input netCDF datasets: a domain dataset specifying the model grid domain and an SST dataset. The SST dataset contains either yearly climatological or multiyear SST data along with the SST domain grid.
To obtain input datasets, the data ocean model first checks in the current working directory for the required file. If the file is not there, the directory specified by the namelist variable DATA_DIR (see below) is examined. If that search is also unsuccessful, the full pathname on disk is finally checked.
On startup, docn reads in model domain data from a netCDF file. Data exchanged with the coupler will be on this model domain. The model domain dataset contains values for the longitude grid cell centers, latitude grid cell centers, longitude grid cell vertices, latitude grid cell vertices, grid cell areas and domain mask. Memory is dynamically allocated at startup for variables dependent on the model domain grid.
The 2d domain mask identifies land points. A mask value of 0 indicates land points (i.e. not in the model's domain) and negative values indicate land-locked regions (e.g. the Caspian Sea).
Two domain datasets are currently provided with the distribution:
Both of these datasets correspond to non-rectilinear grids.
On startup, the data ocean model reads in SST data from a netCDF file specified by the namelist variable DATA_FILE (see section 3). This file contains either annual or multiyear SST data (in degrees Celsius) along with corresponding SST domain grid information.
An annual SST dataset contains 12 months of climatological SST data (presumably monthly mean fields). A multiyear dataset may contain monthly data spanning more than one year. Annual SST data is cycled, whereas multiyear SST data is not. If the requested model date lies outside the time range for the multiyear SST data, the model will exit with an error statement.
If the SST domain grid is in rectilinear coordinates, docn will interpolate the input SST data from the SST domain grid to the model domain grid. SST grids that are in rectilinear coordinates will contain one dimensional x and y coordinate arrays.
If the SST domain grid is in non-rectilinear coordinates, the SST domain grid MUST be identical to the model domain grid since docn currently does not perform interpolations from one non-rectilinear coordinate grid to another. Non-rectilinear SST domain grids will contain two dimensional x and y coordinate arrays.
An annual SST climatological dataset, sst.str_970911.nc, is provided with the distribution. This dataset is in rectilinear coordinates and therefore can be used with any domain dataset provided. If using this dataset, the namelist variable DATA_FORM, specifying whether the input dataset contains annual or multiyear data, must be set to 'annual'. Furthermore, the namelist variable, DATA_SSTNAME, which specifies the netCDF variable name for the SST data, must be set to 'T'.
Two multiyear SST datasets are also provided with the distribution:
It is important to note that these datasets can only be used only with the corresponding domain datasets, domain.gx1v3_010723.nc and domain.gx3_010202.nc. If these multiyear SST datasets are used, then DATA_FORM must be set to 'multiyear' and DATA_SSTNAME must be set to 'SST_cpl'. Furthermore, the namelist variables DATA_LONNAME and DATA_LATNAME must be set to 'xc' and ''yc', respectfully. They SHOULD NOT be set to nlat and nlon.
On startup, the data ocean model reads an input namelist parameter file from stdin.ocn.