CCM3 is normally run with prescribed sea surface temperatures (the Data Ocean Model option or DOM). It may also be run with the Slab Ocean Model (SOM), a thermodynamic model of the ocean mixed layer. A user familiar with running CCM3 with prescribed SST's can easily use SOM.
There are three basic changes needed to run CCM3 with SOM: (1) enabling SOM in the build script (2) using a special SOM initial dataset; and (3) using a special SOM SST dataset, in place of the prescribed SST dataset.
To enable SOM when building the executable, the token COUP_SOM in the misc.h file must be #defined (if using one of the CCM build scripts, this is done by setting the environment variable OCEAN to "som"). This will also include the "som" directory in the "Filepath" which will link the SOM subroutines into the executable.
To run the CCM3 executable with SOM, a special initial conditions dataset must be used. This dataset contains all the standard initial fields, with the addition of SNOWH (snow liquid water equivalent depth, in meters), and SICTHK (sea ice thickness, in meters). Also, a special SST dataset is required, containing twelve monthly-mean fields of ocean mixed-layer depth (MLD, in meters), and ocean heat flux (QO, in W/m2). Refer to "Running with the Slab Ocean Model Component" for a description of the SOM input dataset.
The output of CCM3 with SOM enabled is the same as a run with prescribed sea surface temperatures, except that the field SICTHK is added to the output history files. In addition, the field TS1 over ocean now represents the computed ocean mixed-layer temperature, or the top level sea ice temperature (when sea ice is present), with TS2, TS3, TS4 the lower layer sea ice temperatures, SNOWH the snow cover on sea ice, and SICTHK the sea ice thickness.
Apart from the changes just mentioned, the running of CCM3 with SOM is exactly like that with prescribed SST's. Thus, the discussion on building and running CCM3 in Sec. 2.1 is applicable to using SOM also.
Note: Currently we don't have the necissary input datasets to run CCM3.6.6. with SOM. These datasets
will be provided at a later date. You can use the SOM datasets provided with CCM3.2 and convert
them to netCDF (using ccm2nc), making sure you also put the SGH
field on the initial condition dataset.
However, you should be aware of the fact that the CCM3.2 datasets will be in slight imbalance with
CCM3.6.6, and as such we can not recommend using these datasets for long simulations.
Questions on these pages can be sent to... erik@ucar.edu .
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