CTSM Quickstart Guide for Users

Quick start

To download and start using CTSM, pointing to the latest release code, execute the following commands:

``git clone -b release-clm5.0 https://github.com/ESCOMP/CTSM.git clm5.0``

``cd clm5.0``

``./manage_externals/checkout_externals``

If you later switch the version you have checked out by running git checkout, be sure to rerun ./manage_externals/checkout_externals in order to obtain the correct versions of the external components.

For further documentation, quick start, diagnostics, model output and references, see

• CTSM5.0 release

and

https://escomp.github.io/ctsm-docs/

Details on these commands

The above git clone command checks out the release-clm5.0 branch (you can confirm this by running git branch from inside the clm5.0 directory). If you'd prefer to use the latest development version, you can leave off -b release-clm5.0; this will give you the master branch by default. The master branch is a good starting point for model development, but generally should not be used for scientific production runs. After cloning the code, you can also run git tag to see a list of available tags that you can check out. However, note that tags prior to clm4_5_18_r273 will not run (they are included only for historical reference).

The checkout_externals command downloads the external components needed to build and run CTSM: CIME, MOSART, FATES, etc. For more details on this tool, including instructions for changing the versions of these externals, see the file README_EXTERNALS.rst at the top level of your CTSM directory.