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 want to contribute changes to the model see the "CTSM Quickstart guide for Developers" below which recommends using the main development branch rather than the release branch we show here.

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, quickstart guides, diagnostics, model output and references, see

• CTSM5.0 release page
• CESM Quickstart guide (Note that same script commands used for CLM land-only)
• CTSM User's guide and Technical Description
• CTSM Quickstart guide for Developers

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 However, note that tags prior to clm4_5_18_r273 will not run (they are included only for historical reference).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.