Yes, this value indicates that information about this field was not communicated by the authors and remain unknown. Please see this page for details about all undefined values.

  Yes, this is normal and corresponds to transitions of lines which are presently not completely theoretically described. These kinds of transitions have been kept especially for planetary studies, when they are supposed to be helpful for the understanding of unknown atmospheric composition.

  This temperature is 296 K.

  Because of their atmospheric spectroscopic interest, certain compounds corresponding to heavy molecular species such as such as: chlorofluorocarbons (CFC_s), hydrochlorofluorocarbons (HCFC_s), SF₆, and oxides of nitrogen (for example, N₂O₅) have been introduced in the GEISA cross-sections sub-database. The reason was that it became evident that spectroscopic information on individual spectral lines belonging to this kind of molecules could not be reasonably described in the traditional GEISA individual lines sub-database format (i.e. via, line wavenumber, intensity, halfwidth, etc.). The following approach was adopted to report spectral absorption cross-sections measured at atmospheric conditions:

The absorption cross-sections are determined through the following expression:

σ(ω) = (ln [Ι₀ (ω) / Ι (ω)]) / ηι

where ω is a wavenumber(cm^-1); σ(&omega) is the absorption cross-section (cm² molecule^-1); Ι₀ (ω) and Ι (ω) are the intensities, at the wavenumber &omega, of the incident and transmitted radiation, respectively; Ι is the concentration of the molecules (molecule cm^-3) and ι the optical path length (cm), at a temperature T and a pressure P. It is the σ(&omega) value derived from high-resolution experimental data that is cataloged in the GEISA cross-sections sub-database.

It is the σ(&omega) value derived from high-resolution experimental data that is catalogued in the GEISA cross-sections file. It is presented at several (T, P) combinations representing atmospheric layers given in commonly tabulated atmospheric models as well as conditions encountered.

  GEISA is an interactive spectroscopic database which can be exploited in many fields of research, especially radiative transfer simulations. GEISA is designed to facilitate accurate and fast forward calculations of atmospheric radiative transfer using a line-by-line and (atmospheric) layer-by-layer approach.

  The spectroscopic data archived in GEISA are directly provided by authors of published papers. These data could be derived experimentally or theoretically. In fact they represent very often the results of associated expertises and efforts in both aspects.

The GEISA website gives a complete description of the origin of each data file with associated references on authors and related articles.

• GEISA 2011 references
•  GEISA 2015 references

  The detailed format of such an entry is given in this page.

The complete list of molecules and isotopologues can be viewed at this page.

  The GEISA 2011 sub-database of line transition parameters involves 50 molecules (111 isotopic species) and contains 3,807,997 entries, in the spectral range from 10-6 to 35,877 cm^-1.

  There are mainly six options (see this page for further explanations) :

• Information
• Content analysis
• Database extract
• Transition analysis
• Transition list
•  Download access

and also the direct download access

The format has not been changed since the 2003 version. The same fortran reading program can be use (See GEISA format).

The new version is planned for the end of 2021

The “Graphical Tools” topic is a facility to view the contibution of few spectroscopic parameters. There are ” options :

• Database content
• Global position
• Histogram analysis

GEISA has been used as the reference spectroscopic database for the definition of the 4 bands of the CNES/Microcarb. An example of a “global position” visualization of H2O and CO2 isotopologues for the band 3 (strong CO2 band at 1.6 µm) is given here.