1.1.8. Quickstart

Running the CLM requires a suite of UNIX utilities and programs and you should make sure you have all of these available before trying to go forward with using it. If you are missing one of these you should contact the systems administrator for the machine you wish to run on and make sure they are installed.

List of utilities required for CESM in the Software/OS Prerequisites section of the CESM User’s Guide.

• UNIX bash shell (for some of the CLM tools scripts)

• NCL (for some of the offline tools for creating/modifying CLM input datasets)

• Python

Before working with CTSM1 read the CESM QuickStart Guide. Once you are familiar with how to setup cases for any type of simulation with CESM you will want to direct your attention to the specifics of using CLM.

For some of the details of setting up cases for CTSM1 read the README and text files available from the $CTSMROOT/doc directory (see the “CLM Web pages” section for a link to the list of these files). Here are the important ones that you should be familiar with:

• README file describing CTSM1 describing the directory structure.

• The IMPORTANT_NOTES.md file covers important things for users to know when using the model. Its content is given in the next chapter on Scientific Validation.

• The ChangeLog/ChangeSum talk about advances in different versions of CLM. The content of these files is largely explained in the previous chapter on What is New with CTSM1.

• The release-clm5.0.ChangeLog gives the specific changes that have gone on the release-clm5.0 branch. clm3_0_ChangeLog, clm4_0_ChangeLog, clm4_5_ChangeLog gives the changes that culimated in that given version of the CLM.

Note other directories have README files that explain different components and tools used when running CLM and are useful in understanding how those parts of the model work and should be consulted when using tools in those directories. For more details on configuring and customizing a case with CLM see Setting Up and Running a Case.

The Quickstart.GUIDE (which can be found in $CTSMROOT/doc) is repeated here.

# Quick-Start to Using NUOPC Scripts for ctsm6_0
---

## Assumptions:

You want to use Derecho with ctsm6_0 BGC
to do a CTSM simulation with data atmosphere and the
latest CRUJRA atm forcing files and settings. You also want to cycle
the CRUJRA atm data between 1950 to 2010 and you want to run at
0.9x1.25 degree resolution.

## Process:

   ### Create the case

``` shell
   cd cime/scripts

   ./create_newcase --case <testcase> --mach derecho --res f09_t232 -compset I2000Clm60BgcCrop
   # (./create_newcase -help -- to get help on the script)

   # Setup the case

   cd <testcase>
   ./xmlchange id1=val1,id2=val2  # to make changes to any settings in the env_*.xml files
   ./case.setup
   #(./case.setup -help -- to get help on the script)

   # Add any namelist changes to the user_nl_* files

   $EDITOR user_nl_*

   # Compile the code

   ./case.build

   # Submit the run

   ./case.submit

```

## Information on Compsets:

     "I" compsets are the ones with CTSM and NUOPC driver and CDEPS data models without ice and ocean.
     Most of the "I" compsets are for clm6_0 physics and use the CRUJRA-2024 data with solar following
     the cosine of solar zenith angle, precipitation constant, and other
     variables linearly interpolated in time (and with appropriate time-stamps on
     the date). Previous CMIP6 simulations with clm5_0 physics used GSWP3 atmospheric forcing.

     To get a list of the "I" compsets use the `query_config` utility in `cime/scripts`

``` shell
    cd cime/scripts
    ./query_config --compsets clm
```

## Automatically resubmitting jobs:

   After doing a short simulation that you believe is correct

``` shell
   ./xmlchange CONTINUE_RUN=TRUE

   # Change RESUBMIT to number greater than 0, and CONTINUE_RUN to TRUE...

   ./case.submit
```