absolute path

The full path to a file, e.g., /example/foo/bar.txt. An absolute path should always start with /. As opposed to a relative path.


See compile.

build directory

A directory where build configuration settings are stored, and where intermediate build files like object files, module files, and libraries are stored.

checkpoint file

See restart file.


Generating an executable program from source code (which is in a plain-text format).


The software libraries that are needed to compile GCHP. These include HDF5, NetCDF, and ESMF. See Software Requirements for a complete list.


The software packages and software configuration that are active in your current terminal or script. In Linux, the $HOME/.bashrc script performs automatic configuration when your terminal starts. You can manually configure your environment by running commands like source path_to_a_script or with tools like TCL or LMod for modulefiles. Software containers are effectively a prepackaged operating system + software + environment.

gridded component

A formal model component. MAPL organizes model components with a tree structure, and facilitates component interconnections.


The MAPL gridded component that handles model output. All GCHP output diagnostics are facilitated by HISTORY.

relative path

The path to a file relative to the current working directory. For example, the relative path to /example/foo/bar.txt if your current working directory is /example is foo/bar.txt. As opposed to an absolute path.

restart file

A NetCDF file with initial conditions for a simulation. Also called a checkpoint file in GCHP.

run directory

The working directory for a GEOS-Chem simulation. A run directory houses the simulation’s configuration files, the output directory (OutputDir), and input files/links such as restart files or input data directories.


A file that scripts a sequence of commands. Typically a bash that is written to execute a sequence of commands.

software environment

See environment.


A cubed-sphere grid that is “stretched” to enhance the grid resolution in a region.

target face

The face of a stretched-grid that is refined. The target face is centered on the target point.


A command-line.