SOM (slab ocean model)

There are signifcant differences between the way the slab ocean model (SOM) was run with CAM3, and the new way that it is run with CESM/CAM4. For example, CESM/SOM now runs within the full CESM model, including the coupler, using active atmosphere, land, and ice components, and a slab ocean. The most significant difference is that SOM now requires q-fluxes from the coupled model system (rather than observations). One must have either run the fully coupled system first (or have an available run to use) to obtain q-flux, mixed layer depth, U,V,S, T information from the ocean (POP) output. In addition, SOM now runs on the ocean (POP) grid (not the CAM grid). Therefore, coupler mapping files are required to run SOM.

For more information see:  ~models/ocn/docn/tools/pop_som_frc/SOM.pdf

Table 1:  Summary of differences between SOM with CESM1 and CCSM3

CCSM3 SOM (CAM3)

CCSM4/CESM1 (CAM4/CAM5)

requires SST,HXML on CAM grid

requires SST,U,V,S,HXML on POP grid

thermodynamic ice only; prescribed ice (CAM grid)

fully active ice model (CICE); POP grid

runs on CAM grid

runs on POP grid

does not require a CCSM3 run:
modern: uses obs
paleo: uses ccsm3 paleo run

requires a CCSM4/CESM1 run
for both modern and paleo

no mapping files required

requires mapping file

tools: definemld, defineqflux

cesm code base:
~models/ocn/docn/tools/pop_som_frc

includes: pop_frc.csh, pop_frc_mlt.ncl, pop_frc_mlann.ncl, pop_ffc_interp.ncl, README, and SOM.pdf