CESM

Model description

The Community Earth System Model (CESM) is a fully-coupled, community, global climate model that provides state-of-the-art computer simulations of the Earth's past, present, and future climate states. The CESM project is supported primarily by the National Science Foundation (NSF). Administration of the CESM is maintained by the Climate and Global Dynamics Laboratory (CGD) at the National Center for Atmospheric Research (NCAR).

For the latest CESM release and CESM2 components see CESM2 documentation.

Downloading CESM2

Following CESM2 Quick Start Guide and CESM2 github instructions.

Clone the repository

git clone https://github.com/escomp/cesm.git my_cesm_sandbox

This will create a directory my_cesm_sandbox/ in your current working directory.

Checkout the CESM tag

• Go into the newly created CESM repository

cd my_cesm_sandbox

• Determine what version of CESM you want. To see what versions of CESM2 are available,

git tag --list 'release-cesm2*'

• Checkout a specific CESM release tag type, for example CESM2.1.0:

git checkout release-cesm2.1.0

NOTE: the latest release might not be available yet for public use and this might cause issues in the next step, forcing you to need to start over. See the note in the next step for more information.

Run checkout_externals

To checkout all the individual model components, run the script manage_externals/checkout_externals.

• This script requires Python 2.7.x (installed in HYDRA /share/anaconda2/bin/) to run, so we need to change the Python interpreter in the header of checkout_externals. To do so:

sed -i -e 's!/usr/bin/env python!/share/anaconda2/bin/python!' ./manage_externals/checkout_externals

• Now run the script:

./manage_externals/checkout_externals

NOTE: If you experience problems such as checkout_externals hanging it is likely that is because you asked the checkout of the latest version which is not yet available for public usage, as suggested in this CESM forum discussion:

[gabriela.raggio@hydra my_cesm_sandbox]$ ./manage_externals/checkout_externals
Processing externals description file : Externals.cfg
Processing externals description file : Externals_CLM.cfg
Checking status of externals: clm, fates, ptclm, mosart, ww3, cime,
cice, pop, cism, rtm, cam,
Checking out externals: clm, mosart, ww3, Password for 'gabriela.raggio':


Command 'svn checkout --quiet
https://svn-ccsm-models.cgd.ucar.edu/ww3/trunk_tags/ww3_190402
/home/gabriela.raggio/my_cesm_sandbox/components/ww3'
from directory /home/gabriela.raggio/my_cesm_sandbox
has taken 300 seconds. It may be hanging.

The command will continue to run, but you may want to abort
manage_externals with ^C and investigate. A possible cause of hangs is
when svn or git require authentication to access a private
repository. On some systems, svn and git requests for authentication
information will not be displayed to the user. In this case, the program
will appear to hang. Ensure you can run svn and git manually and access
all repositories without entering your authentication information.

In my case, I was trying to checkout release-cesm2.1.1. I solved this by starting over. I deleted the previous git clone and made a new git clone (named CESM210). In the new git clone I made a checkout of a previous release (release-cesm2.1.0). After doing so, I had no issues running the checkout_externals as explained here.

• To confirm a successful download of all components:

./manage_externals/checkout_externals -S

This should show a clean status for all externals, with no characters in the first two columns of output, as in this example

[gabriela.raggio@hydra CESM210]$ ./manage_externals/checkout_externals -S
Processing externals description file : Externals.cfg
Processing externals description file : Externals_CLM.cfg
Processing externals description file : Externals_POP.cfg
Processing externals description file : Externals_CISM.cfg
Checking status of externals: clm, fates, ptclm, mosart, ww3, cime, cice, pop, cvmix, marbl, cism, source_cism, rtm, cam, 
    ./cime
    ./components/cam
    ./components/cice
    ./components/cism
    ./components/cism/source_cism
    ./components/clm
    ./components/clm/src/fates
    ./components/clm/tools/PTCLM
    ./components/mosart
    ./components/pop
    ./components/pop/externals/CVMix
    ./components/pop/externals/MARBL
    ./components/rtm
    ./components/ww3

If this is the case, at this point you have a working version of CESM.

Downloading the Input data

*** IMPORTANT: SECTION UNDER CONSTRUCTION***

Input datasets are needed to run the model. CESM input data are available through a separate Subversion input data repository.

• Change check_input_data header so it runs with Python 2.7.x version:

sed -i -e 's!/usr/bin/env python!/share/anaconda2/bin/python!' ./cime/scripts/Tools/check_input_data