Workspaces

Workspaces#

Using CESM effectively requires familiarity with its directory structure. A CESM simulation is organized around several key directories that together form your CESM Workspace.

Throughout this tutorial, you will learn where these directories are located and how they are used to set up, build, run, and analyze CESM simulations.

The five main workspace locations (see figure, below) are:

  1. CESM source code ($SRCROOT)
    Contains the CESM source code, including the CIME infrastructure $CIMEROOT.

  2. Input data directory ($DIN_LOC_ROOT)
    Contains the input datasets required by CESM simulations.

  3. Case directory ($CASEROOT)
    Contains the configuration files for a specific simulation. In CESM terminology, a case is a particular model experiment.

  4. Build and run directories ($EXEROOT and $RUNDIR)

  • $EXEROOT contains the executable and build files.

  • $RUNDIR contains runtime files and model output generated during a simulation.

  1. Archive directory ($DOUT_S_ROOT)
    Stores archived model output after a simulation completes.

We will explore each of these directories in more detail throughout the tutorial.

Note on Terminology

  • A path is the full location of a directory or file in the filesystem.

  • A root is a commonly used path stored in a variable (for example, $SRCROOT or $CASEROOT) that points to a specific part of the CESM workspace.

Workspace Overview#

CESM workspace

Figure: Overview of the CESM Workspace Directories

For the current tutorial on Derecho, the paths are:

  • $SRCROOT = /glade/u/home/$USER/code/my_cesm_code

  • $DIN_LOC_ROOT= /glade/campaign/cesm/cesmdata/cseg/inputdata

  • $CASEROOT = /glade/u/home/$USER/cases/$CASE

  • $CIME_OUTPUT_ROOT = /glade/derecho/scratch/$USER

  • $EXEROOT =/glade/derecho/scratch/$USER/$CASE/bld

  • $RUNDIR =/glade/derecho/scratch/$USER/$CASE/run

  • $DOUT_S_ROOT =/glade/derecho/scratch/$USER/archive/$CASE

Each of these directories contains additional subdirectories and files. Becoming comfortable navigating between them is an important part of working with CESM.

Setting your workspaces#

Before creating and running CESM simulations, you will create directories to store the CESM source code and a directory to store all your case directories.

In the CESM jargon, a case refers to a model simulation.

  • Create CESM Code Directory

Create a workspace location to put your CESM code on Derecho. In all exercises in this tutorial $USER is a placeholder and it refers to NCAR HPC login name. (In the exercises: replace $USER by your login name)

cd /glade/u/home/$USER
mkdir code

  • Create Cases Workspace Location

Create a directory on derecho where all your cases from this tutorial will be located.

cd /glade/u/home/$USER
mkdir cases

  • Other Workspace Locations

You do not need to create the input data directory ($DIN_LOC_ROOT) on NCAR systems, as these datasets are already available in a shared location. This location is shared by all CESM users to save space on the NCAR supercomputer.

Similarly, the build ($EXEROOT), run ($RUNDIR), and archive ($DOUT_S_ROOT) directories are created automatically when you create a CESM case.

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