CESM

General

• National Center for Atmospheric Research (NCAR):

https://ncar.ucar.edu/

• Project site: https://ncar.ucar.edu/what-we-offer/models/community-earth-system-model-cesm
• QuickStart Manual for CESM2.1: https://escomp.github.io/CESM/release-cesm2/index.html

The Community Earth System Model is a fully-coupled global climate model developed in collaboration with colleagues in the research community. CESM provides state-of-the-art computer simulations of Earth's past, present, and future climate states.

CESM2 is built on the CIME framework. The majority of the CESM2 User’s Guide is contained in the CIME documentation.

• CIME: https://github.com/ESMCI/cime
• CIME Manual: https://esmci.github.io/cime/versions/master/html/index.html

The Common Infrastructure for Modeling the Earth (CIME - pronounced “SEAM”) provides a Case Control System for configuring, compiling and executing Earth system models, data and stub model components, a driver and associated tools and libraries.

CESM on ARC

Currently, there are two versions of CESM are installed on ARC, but only one works and supported. The supported version is 2.1.3.

CESM is installed and setup to be used via environmental modules, using the module command.

$ module avail cesm
------------------- /global/software/Modules/4.6.0/modulefiles -------------------
cesm/2.1.1  cesm/2.1.3 

To activate it please load its module:

$ module load cesm/2.1.3

Loading cesm/2.1.3
  Loading requirement: gcc/9.4.0 cmake/3.17.3 git/2.25.0 svn/1.10.6 openmpi/4.1.1-gnu lib/openblas/0.3.13-gnu

This installation of CESM comes with its own dedicated installs of Python and Perl. To verify that the software has been properly activated you can check the locations of some of the commands provided by the install:

$ which python
alias python='python3'
	/global/software/cesm/python/3.10.4/bin/python3

$ which perl
/global/software/cesm/perl/5.34.1/bin/perl

$ which create_newcase
/global/software/cesm/cesm-2.1.3/cime/scripts/create_newcase

If you have any other software modules loaded on ARC, they may interfere with CESM. Please avoid loading too many modules at the same time.

There is a shared data directory, pointed by the DIN_LOC_ROOT environmental variable for CESM data sets. Sharing this storage directory should reduce the amount of data that needs to be downloaded as well as save storage space in users home directories.