GGG

The links on this page point to information for the current GGG version. If you are looking for information about old versions, please see this page.

Some topics on this page require an account on this wiki to access (specifically those dealing with advanced use of GGG or older information which could be confusing). For information on how to get a wiki account, contact tccon_webmaster@gps.caltech.edu.

• Release notes including download instructions
• GGGLicense
• Running GGG
• GGG Version Information
• GGG input, intermediate, and output files
• GGG theoretical basis
  • GGG Overview
• Technical Documents
• GggInputFile
• GGG FAQs
• Future Development
• Future Development post-GGG2020
• Averaging Spectra
• Averaging Kernels
  • Generating averaging kernels
• Using averaging kernels and other auxiliary data for comparison to other profiles
• ColFiles
• EGI
• ErrorScaleFactor
• GeneratingPseudoLinelists
• GeneratingSyntheticSpectra
• I2SAndOPUSHeaders
• IsotopologsDat
• MapFiles
• MavFiles
• ModFiles
• OfficialDataOutputFile
• RunLog
• RunningGFITAndI2S
• SpectralWindowsFile
• Spectroscopy
• SunRun
• TCCONSpectralNamingConvention
• Useful GGG2020 figures
• UsingGGG

GGG is a suite of software tools developed at JPL to determine the abundances of atmospheric trace gases from infrared solar absorption spectra. This software evolved from the ODS software (Norton and Rinsland, 1990) used for the Version 2 analysis of ATMOS data, but has incorporated many improvements. The most complicated program in the GGG suite is GFIT, the spectral fitting code. GFIT has been used for the analysis of MkIV spectra (balloon, aircraft, and ground-based), plus the Version 3 analysis of ATMOS shuttle spectra (Irion et al. 1999). Additionally, GFIT has been used for the analysis of spectra from several ground-based FTIR spectrometers (e.g. Notholt et al., 1997, Notholt et al., 1997).

We have tried to divide the necessary functionality among several programs rather than have a single program that does everything. You can then use a script (e.g., master.sh) that performs the needed end-to-end processing. All data files are ASCII, with the exception of the (OPUS-format) spectra and the NCEP NCDF-format analyses over which we have no control.

The image attached below shows a block diagram representing the relationship between the various components (programs and data files) of the GGG suite. The most important single file is the runlog. This contains all the information needed to perform a quantitative analysis of the named spectra, without needing to read their headers. The runlog is used by no fewer than 4 different programs.

Any bug reports or GFIT requests should be filed on https://gggbugs.gps.caltech.edu. You will have to register to use the site, but it's quick and easy to do.

©1986-2011. California Institute of Technology. All Rights Reserved. U.S. Government sponsorship under contracts NAS7-1407 and/or NAS7-03001 acknowledged. Any commercial use must be negotiated with the Office of Technology Transfer at the California Institute of Technology.