Glossary

benchmark runs

Selected validation runs made with each release of the model. These runs can be made using Python code in the tgcmrun/ directory.

benchmarks/

Directory in the model root directory containing shell scripts that call tgcmrun/ for making benchmark runs, some utility scripts, and a subdirectory postproc/ containing scripts that do post-processing on benchmark results. See Benchmark Runs for more information. Benchmark results (plots) for version tiegcm2.0 are available here: Benchmarks Results

continuation run

A continuation run continues from the last output history of the previous run. That history (START time) must be on the first OUTPUT file provided by the namelist input file. A continuation run must not specify a SOURCE file or SOURCE_START time. See also Continuation Run

diagnostic fields

A list of diagnostic fields are available to be saved on secondary history files. See section Saving Diagnostic Fields.

datadir

Directory containing startup history and data files necessary for running the model. This is specified with the tgcmdata shell variable in the job script.

doc/

Subdirectory under the modeldir containing documentation, e.g., the User’s Guide, Model Description, Release Notes, etc.

ESMF

“Earth System Modeling Framework”. The ESMF library is used in the electro-dynamo code (pdynamo.F in version 2.0 or later) for regridding between geographic and geomagnetic grids in an mpi environment. This is open software that can be downloaded at https://www.earthsystemcog.org/projects/esmf/download/ If you build the ESMF library, it should be built with the same compiler with which the model is built.

execdir

The model execution directory. This is the directory where the model is built and executed. It should be on a large temporary disk, capable of storing model object and module code, netCDF output history files, and other data. When a job script is executed from a working directory, the execdir is created if it does not already exist. During a model run, output history files are written to the execdir. The execdir is set in the job script. See also Execution Directory

geomagnetic coordinates

The electro-dynamo fields (electric potential, electric field, and ion drift velocities) are calculated on a geomagnetic grid, see magnetic coordinates

Globus

Globus Data Sharing Service for scientific research. The tiegcm2.0 benchmark history files and post-processing are available via Globus. See Model Output History Files of the tiegcm2.0 Benchmark runs for more information.

history

A model history records the state of the model at a discrete instant in model time. One or more histories are stored in netCDF history files.

initial run

An initial run is started from a history on a SOURCE file (see also SOURCE_START). Subsequent continuation runs do not provide SOURCE or SOURCE_START, but rather search for the START time on the first OUTPUT history file provided in the namelist input, and continue the run from there.

job script

A csh script in the scripts/ directory which, when executed, will build and execute the model. The user defines a few shell variables in the job script, such as the modeldir, and the namelist input. See example job script for Linux desktops, and job script for Super computer See Using the job scripts to set up and submit a model run for more detailed information.

model time

TIEGCM model time is represented by an integer triplet: day,hour,minute, where day is the julian day of the year, and hour is the ut. The variable for model time on history files is mtime(3,ntimes). For example, a history file may contain 24 hourly histories for day 80: mtime = 80,1,0, 80,2,0, ... 81,0,0.

modeldir

The model root directory. This directory typically contains subdirectories src/ (model source code), scripts/ (utility scripts), doc/ (documentation), and benchmarks/. The modeldir is available via download, and is typically a subdirectory of the model working directory (workdir). See also Model Directory

namelist input

The model reads user specified parameters from the namelist input file via f90 standard namelist read. Keyword/Value pairs are read from unit 5, and are validated by the input module (input.F). See also job scripts.

netCDF

TIEGCM output history files are written in netCDF, a self-describing platform-independent data format written and maintained by the UCAR Unidata program.

output

File to receive stdout output from the model. This file will be created if it does not exist, or overwritten if it does exist.

resolution

The TIEGCM can be run in one of two resolutions:

• 5 x 5 deg lat x lon, 2 grid levels per scale height (dz = 0.50)
• 2.5 x 2.5 deg lat x lon, 4 grid levels per scale height (dz = 0.25)

The resolution is set by the “modelres” shell variable in the TIEGCM job script. See also the section on Grid Structure and Resolution.

Note

The 2.5-degree resolution model is available in version 2.0, but it is not fully validated or supported by the public release.

scripts/

Subdirectory under the modeldir containing supporting and utility scripts, including job scripts, the default namelist input file, several Make files, etc.

src/

Subdirectory under the modeldir containing the model source code (*.F, *.h files).

tgcmrun/

Subdirectory under the modeldir. The tgcmrun directory contains Python code to make benchmark runs for the current release. The ‘tgcmrun’ command may be used to interactively submit selected benchmark runs, or tgcmrun can be executed from a shell script using command-line options. There are several run_xxxxx shell scripts there demonstrating how to make benchmark runs.

tgcmdata

A directory path to start-up and other input data files required for running the model. This should be on a large temporary disk. tgcmdata is a csh variable optionally specified in the job script. If not specified, the job script will use the TGCMDATA environment variable. See also job script shell variables.

env var TGCMDATA

A linux environment variable that refers to the tgcmdata. This environment variable may be used when referring to data files in the namelist read file, e.g., “GPI_NCFILE = $TGCMDATA/gpi_xxxxx.nc”. See namelist read files.

tgcmproc_f90

Post-processor and visualizer for TIEGCM netCDF history files. Written in f90, and available at the TIEGCM download site See tgcmproc_f90.

tgcmproc_idl

Post-processor and visualizer for TIEGCM netCDF history files. This processor is Written in IDL with a GUI, and is available at the TIEGCM download site See tgcmproc_idl.

utproc

Post-processor and visualizer for TIEGCM netCDF history files. This processor reads time-series history files and makes ut vs pressure and ut vs latitude contours. It is written in IDL with a GUI, and is available at the TGCM download site. See utproc.

workdir

User-created local working directory. This will typically contain the model root directory modeldir and related namelist input files, job scripts, stdout files, etc. Because the model source files are critical, this should be on backed-up disk, typically under your home directory.

Zp

Vertical log pressure coordinate ln(p0/p) of the TIEGCM. This is the “lev” coordinate on the history files. See the chapter on Altitude Coordinates the NCAR TIEGCM for a detailed explanation of the relationship between Zp and Altitude.