Resources

Repository Structure

To couple MOM6 and CESM, we maintain and incorporate two repositories in CESM: MOM6 and MOM_interface. While the former is the core MOM6 source code that implements the model, the latter encapsulates the core MOM6 repository and facilitates an interface between MOM6 and CESM. This hierarchical repository organization allows us to separate concerns and streamline the implementation of CESM-specific parameterization choices, test suites, tools, and mechanisms without interfering with the core MOM6 repository shared with the greater MOM6 community.

• MOM6: https://github.com/NCAR/MOM6.git

  NCAR's fork of the core MOM6 repository. This codebase is shared with the rest of the MOM6 community and is synchronized with GFDL's main MOM6 fork via routine pull requests. In addition to the common model source code, all model caps (drivers) used by various coupling frameworks, including CESM's MCT and NUOPC caps, are implemented in this core repository.

• MOM_interface: https://github.com/ESCOMP/MOM_interface.git

  A repository to establish CIME compatibility for MOM6 and to interface the core MOM6 source code with CESM. CESM-specific parameterization choices, test suites, tools, and mechanisms are maintained in this repository. The MOM_RPS module that controls runtime parameters and out-of-the-box MOM6 configurations is also implemented in MOM_interface. This repository encapsulates the core MOM6 repository via the manage_externals mechanism. MOM_interface itself is included in the main CESM repository, again, via the manage_externals mechanism.

Understanding files located in the run directory:

The following table summarizes the main files associated with CESM/MOM6, which are located in the run directory (determined by xml variable RUNDIR). Files termed 'IN' are required input files, while files termed 'OUT' appear after the model has been run:

Input file	i/o	Contents	POP's Equivalent
input.nml	IN	Has the necessary fortran namelists for executing MOM6 and controlling non-MOM6 components of the code. This includes the list of MOM-style parameter files to read, usually "MOM_input" and "MOM_override". We rarely change this file in CESM/MOM6.	NA
MOM_input	IN	Contains all the necessary run-time parameters that define this experiment.	namelist_default
MOM_override	IN	Is usually blank except in cases where there are several variants on an example (e.g. with different coordinates).	user_nml_pop
diag_table	IN	List of diagnostics, used by FMS's diagnostic manager.	tavg_contents, tavg_nml
MOM_parameter_doc.all	OUT	Records all the run-time parameters that are not associated with the parallelization.	pop_in
MOM_parameter_doc.short	OUT	Records all the non-default run-time parameters that are not associated with the parallelization.	NA
MOM_parameter_doc.layout	OUT	Records all the run-time parameters that are associated with the parallelization. These parameters are computational and do not affect the numerical solution.	NA
available_diags	OUT	a list of available diagnostics for this particular configuration.	NA
ocean.stats.*	OUT	are ascii and netCDF files with a few key statistics/metrics used for bitwise regression testing by the core-MOM6 team.	$CASENAME.pop.dd
MOM_IC.nc	OUT	file containing the ocean initial conditions.	NA
ocean_geometry.nc	OUT	file describing the topography, Coriolis parameter, grid locations and various other fixed fields from the ocean grid.	NA
Vertical_coordinate.nc	OUT	file describing the variables associated with the vertical coordinate	NA
*.mom6.static.nc	OUT	file describing static variables of the ocean model (e.g., geolon, area, wet, etc). These variables are defined in the diag_table.	NA
*.mom6.sfc_*.nc	OUT	file showing daily means of surface variables of the ocean model (e.g., SST, SSS, SSU, etc). These variables are defined in the diag_table.	NA
*.mom6.frc_*.nc	OUT	file showing daily means of forcing fields of the ocean model (e.g., taux, sensible, evap, etc). These variables are defined in the diag_table.	NA
*.mom6.hm_*.nc	OUT	file showing monthly means of selected variables using the native grid. These variables are defined in the diag_table.	NA
*.mom6.h_*.nc	OUT	this is the ocean model history file used by the CESM postprocessing tool. Variables are defined in the diag_table.	NA
*.mom6.r.*.nc	OUT	ocean model restart file.	*.pop.r.*.nc