Instructions for the Coupled Model

1 How to build?

Instructions on how to build the model can be found here.

We provide a summary of the build process:

1. ml GEOSenv
2. cd <your_working_directory>
3. git clone -b v10.23.1 [email protected]:GEOS-ESM/GEOSgcm.git See here for full details. Its obvious that we are building a set version, i.e., v10.23.1 (released on Nov 18, 20222) which will facilitate reproducibility.
4. cd GEOSgcm/
5. parallel_build.csh

Check if the build was successful

Issue the command:

grep 'exit ' parallel_build.oxx

xx is a number that is generated by slurm when the build job is submitted to queue. If you get:

exit 0

all went okay!

2 How to set up an experiment?

• We use gcm_setup script. See here for instructions.
• Options to be selected are mostly defaults and are same as the uncoupled model, see ⬇️ for differences.

 ...
 ...
 ...
 Enter the Atmospheric Horizontal Resolution code:
 --------------------------------------
          Cubed-Sphere
 --------------------------------------
 c12  --  8   deg 
 c24  --  4   deg 
 c48  --  2   deg 
 c90  --  1   deg 
 c180 -- 1/2  deg (56-km) 
 c360 -- 1/4  deg (28-km)  
 c720 -- 1/8  deg (14-km) 
 c1440 - 1/16 deg ( 7-km) 
           DYAMOND Grids                 
 c768 -- 1/8  deg (12-km) 
 c1536 - 1/16 deg ( 6-km) 
 c3072 - 1/32 deg ( 3-km) 

c180

 ...
 ...
 ...
 Do you wish to run the COUPLED Ocean/Sea-Ice Model? (Default: NO or FALSE)
YES

 Choose an Ocean Model: (Default: MOM5)
 MOM5
 MOM6
MOM6

 Enter the Ocean Lat/Lon Horizontal Resolution: IM JM (Default: 360 210)
1440 1080
 Enter the Ocean Model Vertical Resolution: LM (Default: 50)
75
 ...
 ...
 ...

The ⬆️ example illustrates how to set up an experiment with MOM6 coupled model at c180x72L (atmosphere), 1440x1080x75L (ocean) resolutions.

Note:

• If the horizontal and/or vertical resolutions are not the default values, it is the user's responsibility to provide all other files and resources for a functional model run. Available configurations/resolutions are:

  • MOM5:
    • c180x72L atmosphere, 1440x1080x50L ocean.
    • c90x72L atmosphere, 360x200x50L ocean.
  • MOM6:
    • c180x72L atmosphere, 1440x1080x75L ocean.
    • c12x72L atmosphere, 72x36x50L ocean.

• Reg configurations with MOM5 coupled model, beaware of this issue.

• Both of the ⬆️ MOM6 coupled model configurations are being actively used and developed.

3 How to run?

In the experiment directory, use gcm_run.j script (this step is same as for the uncoupled model) to run the model.