The Slab Ocean Model (SOM) configuration enables a simple but tightly
coupled ocean modeling component combined with a thermodynamic sea ice
component based on the CCSM3 sea ice model. This configuration of the
atmospheric model allows for a fully-interactive treatment of surface
exchange processes in the CAM 3.0. The ocean prognostic variable is the
mixed layer temperature , while the thermodynamic sea ice model
treats snow depth, surface temperature, ice thickness, ice
fractional coverage, and internal energy
at four layers for a single thickness category. The ocean mixed layer
contains an internal heat source
(also called a
flux), whose
values are generally specified by a CAM control run, representing
seasonal deep water exchange and horizontal ocean heat transport. For
example, using prescribed sea surface temperatures and sea ice
distributions, the net surface
energy flux over the ocean surface can be evaluated to yield the heat
source
. Additional exchange of heat occurs between the ocean mixed
layer and the sea ice model during ice formation and ice melt. To
ensure the CAM 3.0 SOM sea ice simulation compares well to the observed
ice distribution, and to moderate sea ice changes in climate change
experiments, the
flux term is adjusted under the ice in a globally
conserving manner.