An ocean mixed layer model has been incorporated into the ice model since the CCSM data ocean component does not allow frazil ice growth to occur. This is due to the minimum ocean mixed layer temperature being fixed at the freezing point. It is a simple slab ocean mixed layer model that is forced using output from a POP ocean simulation. More details on the physics of the ocean mixed layer model can be found in the Physics Documentation. This option can be run with the gx3v5 or the gx1v3 grid.
The namelist variables for the ocean mixed layer model within the ice model are shown in Table 8. To use the slab ocean model, $OCEANMIXED_ICE must be set to .true. in the namelist. There are commands in the scripts that will copy the grid dependent forcing file from the input data directory to the executable directory and rename it oceanmixed_ice.nc. This is generally not the best ocean forcing, but can be used as a template for creating an ocean forcing file appropriate for the application.
The variable $OML_ICE_SST_INIT determines the initial sea surface temperature. For an initial or startup run, this variable should be set to true, and the January 1 value of the sea surface temperature will be read from the POP forcing file. For continuation runs, the value of $OML_ICE_SST_INIT should be set to false, and sea surface temperature and the freeze/melt potential will be read from a restart file. This variable will be automatically set in the scripts depending on the run type. When the slab ocean mixed layer within the ice model is used, the data that is received from the coupler from the ocean component (docn or POP) is overwritten by the values calculated by the ocean mixed layer. Therefore, it is not appropriate to use the ocean mixed layer option coupled to an active ocean model. Also, using the ice model with the slab ocean mixed layer turned on, coupled to an active atmosphere and a data ocean model will require changes to the coupler, since the ocean values calculated in the ice model will not be sent to the coupler and received by the atmosphere component.