Organization of the code¶

The MOM6 source code is divided into a tree of directories (folders) to group related code (e.g. src/core) or similar modules (e.g. src/parametizations/vertical).

The highest level of directories are:

src/: Code underneath src/ is always required and compiled.
config_src/: Under config_src are various drivers and memory configuration sources that can only be compiled in limited configurations. See config_src/
pkg/: Packages (source code) from other sources/parties only some of which might be used. We include the entire package as a sub-module but use symbolic-links to extract the parts the MOM6 uses.
docs/: The directory that contains this documentation, namely that beyond the in-code API documentation. Some of the files are configuration files needed for running doxygen and sphinx. Most documentation in this folder is in the form of reStructuredText (.rst) files.
.testing/: A directory for running tests on MOM6. These are some of the smaller/simpler examples that MOM6 can run out of the box, without large netCDF files.

The directory tree is:

MOM6
├── config_src
│   ├── drivers
│   │   ├── FMS_cap
│   │   ├── ice_solo_driver
│   │   ├── mct_cap
│   │   ├── nuopc_cap
│   │   ├── solo_driver
│   │   └── unit_drivers
│   ├── external
│   │   ├── GFDL_ocean_BGC
│   │   └── ODA_hooks
│   ├── memory
│   │   ├── dynamic_nonsymmetric
│   │   ├── dynamic_symmetric
├── docs
│   └── images
├── pkg
│   ├── CVMix-src
│   │   ├── ...
│   │   └── src
│   │       ├── drivers
│   │       └── shared
│   └── GSW-Fortran
├── src
│   ├── ALE
│   ├── core
│   ├── diagnostics
│   ├── equation_of_state
│   │   └── TEOS10
│   ├── framework
│   ├── ice_shelf
│   ├── initialization
│   ├── parameterizations
│   │   ├── CVmix -> ../../pkg/CVMix-src/src/shared
│   │   ├── lateral
│   │   └── vertical
│   ├── tracer
│   └── user
└── .testing
    ├── tc0
    ├── tc1
    ├── tc1.a
    ├── tc1.b
    ├── tc2
    ├── tc2.a
    ├── tc3
    └── tc4

config_src/¶

memory/dynamic_nonsymmetric/, memory/dynamic_symmetric/: One or none of config_src/memory/dynamic_nonsymmetric/ or config_src/dynamic_symmetric/ can be included at compile time. If neither is used then a MOM_memory.h file specific to the model configuration must be present - this is known as a”static” compile with fixed layout and domain shape.
external/: Contains “null” modules providing the API to optional components to use with MOM6. Currently available are ocean data assimilation (ODA_hooks) and the GFDL ocean bio-geochemistry model (GFDL_ocean_BGC). When building MOM6 in stand-alone ocean-only mode these modules should be compiled in. To use the actual ODA or BGC, add the appropriate source to the search paths .
infra/FMS1: Contains MOM6-specific thin wrappers to all of the FMS types and routines that are used by MOM6. The code in this directory should only be called by the infrastructure-agnostic code in src/framework.
drivers/solo_driver/: This driver produces an ocean-only executable with no other coupled components (no sea-ice, no atmosphere, etc.). It is the simplest configuration and fastest to compile and thus used for a lot of testing.
drivers/FMS_cap/: This driver provides an interface for the GFDL coupler to call. It requires compiling MOM6 along with at least a sea-ice model and possibly all other components in a coupled model.

src/¶

core/: The dynamical core modules (except for the ALE remapping/regridding).
ALE/: Functions for remapping from between arbitrary vertical grids and generating grids.
diagnostics/: Some diagnostic calculations
equation_of_state/: Various equations of state (linear; Wright, 1997; TEOS-10; …).
framework/: Low-level wrappers for communication, diagnostics management, parsing of input parameters, time management, CPU clocks.
initialization/: Initialization of the horizontal grid, vertical coordinate, and the state.
parameterizations/lateral: Sub-grid scale parameterization with fluxes primarily oriented in the lateral direction.
parameterizations/vertical: Sub-grid scale parameterization with fluxes primarily oriented in the vertical direction, including the top and bottom boundary layer schemes.
tracer/: Everything to do with tracers, including advection and isopycnal stirring.
user/: Initialization and forcing for specific (coded) configurations.