HITRAN on the Web

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Simulation results

Page is intended for working with gas mixture spectra obtained by simulation (Fig. 1).


Fig. 1. The page of obtained molecular spectra

The viewport of the browser window is a set of tabs. The default Spectra tab shows the results of spectra simulation. For each type of simulated spectrum, there is a table of available spectra. The table contains the description of each spectrum and the values of the parameters used in the simulation. The number of columns in the table depends on the simulation type, because different types of simulated spectrum are described by different number of parameters. By default, the page displays a table for the last simulated type of spectrum. In addition to the columns containing the values of the simulation parameters, the table contains some additional columns. We describe them more detailed.

The leftmost column of the table contains checkboxes allowing you to select spectra to perform the actions indicated on the buttons below the table. The checkbox in the table header allows to select all spectra or deselect all spectra.

The next column In is available only to registered users and informs about where is the spectrum saved: in the user's archive  (U) or in a temporary storage  (C: cache).

The Description column contains the name of the gas mixture.

The Plot column shows whether the graphical representation of the spectrum is available. The portal sites provide the ability of interactive manipulation with graphical data in the client browser. The attempt to build a plot for too large data file can cause the "hang" of the browser due to the long time required for building of the plot  or exhausting the available RAM. The column can contain the values Y (Yes, the plot is available) or N (No, the plot is not available). Since there is a possibility of plotting several spectra, the choice of a number of spectra to plot may lead to similar results. According to our estimates, the total number of pairs of points (X,Y) for the plot should not exceed 500 thousand, although this limit can vary significantly depending on the parameter (primarily the amount of available RAM) of the user's computer.
The Size column specifies the file size in Kbytes.

The colored box in the next column has the same color as the color of square in a pop-up message about starting of the spectrum simulation. It can be useful for visual identification of the spectrum.

The last column allows to perform some actions with the spectrum. It contains 3 buttons. The button  allows you to open a tab containing the  numerical  view of the spectrum. The button  is attended for download the text file containing the spectrum in numerical form. The button  allows you to delete a spectrum.
 
Buttons below the table

The button Plot selected allows you to plot selected spectra. The plot is displayed in a separate tab.

The button Delete selected allows you to delete all marked spectra.

The button Save selected allows you to move marked spectra from temporary storage to the user's archive. Available only to registered users.

Other tabs are used for graphical and numerical representation of selected spectra and appear on the user's requests.
 
Format of numerical data
Numerical files are displayed in View tabs at the click of a button  and downloaded to a user's computercontain several header lines starting with " # " character, which give a verbal description of the contents of the file and the parameter values of the simulated spectrum. Below are the data columns.

For spectral functions the data contains 2 or 3 columns. The first one is the wavenumber WN, and the rest are value(s) of appropriate spectral function. In the case of a list of spectral lines the file contains multiple columns. Each column contains values of one of parameter of spectral line described in the Generalities section. Currently HITRAN-2004 file format of spectral line parameters is supported [1, p.143]. Consult to Generalities/Numerical representation of the results for more detaild information.
 
Remark
As described in the section Spectral functions of the Generalities, the spectral function is obtained by a sequence of transformations on a list of spectral lines (linelist) extracted from the database. For example, to obtain the absorption function first the linelist is retrieved, then the function of the absorption coefficient is calculated for this linelist, and on the basis of it is the absorption function is obtained. To build any low-resolution spectrum the appropriate high-resolution spectrum must first be built. Now, all intermediate results of  the spectrum simulation is also available on this page.

References

  1. L.S. Rothman, D. Jacquemart, A. Barbe, D.C. Benner, M. Birk, L.R. Brown, M.R. Carleer, C. Chackerian Jr., K. Chance, L.H. Coudert, V. Dana, V. Malathy Devi, J.-M. Flaud, R.R. Gamache, A. Goldman, J.-M. Hartmann, K.W. Jucks, A.G. Maki, J.-Y. Mandin, S.T. Massie, J. Orphal, A. Perrin, C.P. Rinsland, M.A.H. Smith, J. Tennyson, R.N. Tolchenov, J. Vander Auwera, P. Varanasi, G. Wagner, The HITRAN2004 Molecular Spectroscopic Database. J. Quant. Spectrosc. Radiat. Transfer, 96, 139-204 (2005).