Engineering topics
Rothman, L. S.
Publications and source records attributed to Rothman, L. S..
The HITRAN2016 molecular spectroscopic database
This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is comprised of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 200 additional significant molecules have been added to the database.
Comment on "Radiative forcings for 28 potential Archean greenhouse gases" by Byrne and Goldblatt (2014)
In the recent article by Byrne and Goldblatt, "Radiative forcing for 28 potential Archean greenhouse gases", Clim. Past. 10, 1779–1801 (2014), the authors employ the HITRAN2012 spectroscopic database to evaluate the radiative forcing of 28 Archean gases. As part of the evaluation of the status of the spectroscopy of these gases in the selected spectral region (50–1800 cm -1 ), the cross sections generated from the HITRAN line-by-line parameters were compared with those of the PNNL database of experimental cross sections recorded at moderate resolution. The authors claimed that for NO 2 , HNO 3 , H 2 CO, H 2 O 2 , HCOOH, C 2 H 4 , CH 3 OH and CH 3 Br there exist large or sometimes severe disagreements between the databases. In this work we show that for only three of these eight gases a modest discrepancy does exist between the two databases and we explain the origin of the differences. For the other five gases, the disagreements are not nearly at the scale suggested by the authors, while we explain some of the differences that do exist. In summary, the agreement between the HITRAN and PNNL databases is very good, although not perfect. Typically differences do not exceed 10 %, provided that HITRAN data exist for the bands/wavelengths of interest. It appears that a molecule-dependent combination of errors has affected the conclusions of the authors. In at least one case it appears that they did not take the correct file from PNNL (N 2 O 4 (dimer)+ NO 2 was used in place of the monomer). Finally, cross sections of HO 2 from HITRAN (which do not have a PNNL counterpart) were not calculated correctly in BG, while in the case of HF misleading discussion was presented there based on the confusion by foreign or noise features in the experimental PNNL spectra.
The HITRAN database - 1986 edition
A description and summary of the latest edition of the AFGL high-resolution transmission molecular absorption database (HITRAN) parameters are presented. This new database combines the information for the seven principal atmospheric absorbers and twenty-one additional molecular species previously contained on the AFGL atmospheric absorption line parameter compilation and on the trace gas compilation. In addition to updating the parameters on earlier editions of the compilation, new parameters have been added to this edition such as the self-broadened half-width, the temperature dependence of the air-broadened half-width, and the transition probability. The database contains 348,043 entries between 0 and 17,900/cm. A FORTRAN program is now furnished to allow rapid access to the molecular transitions and for the creation of customized output. A separate file of molecular cross sections of 11 heavy molecular species, applicable for qualitative simulation of transmission and emission in the atmosphere, has also been provided.
Atlas of Absorption Lines from 0 to 17900 Cm (sup)-1
Plots of logarithm (base 10) of absorption line strength versus wavenumber from 0 to 17900/cm(sup)-1 are shown for the 28 atmospheric gases (H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, NH3, HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, H2CO, HOCl, N2, HCN, CH3Cl, H2O2, C2H2, C2H6, PH3), which appear in the 1986 Air Force Geophysics Laboratory high-resolution transmission molecular absorption data base (HITRAN) compilation, and for O(P-3), O-18 isotopic ozone, and HO2 from the 1984 JPL compilation in the 0- to 200/cm(sup)-1 region, and infrared solar CO lines at 4500 K. Also shown are plots of logarithm (base 10) of approximate infrared absorption cross sections of 11 heavy molecules versus wavenumber. The cross-section data cover 700 to 1800/cm(sup)-1 and are included as a separate data file in the 1986 HITRAN database.
Spectroscopic database
Several aspects of quantitative atmospheric spectroscopy are considered, using a classification of the molecules according to the gas amounts in the stratosphere and upper troposphere, and reviews of quantitative atmospheric high-resolution spectroscopic measurements and field measurements systems are given. Laboratory spectroscopy and spectral analysis and prediction are presented with a summary of current laboratory spectroscopy capabilities. Spectroscopic data requirements for accurate derivation of atmospheric composition are discussed, where examples are given for space-based remote sensing experiments of the atmosphere: the ATMOS (Atmospheric Trace Molecule) and UARS (Upper Atmosphere Research Satellite) experiment. A review of the basic parameters involved in the data compilations; a summary of information on line parameter compilations already in existence; and a summary of current laboratory spectroscopy studies are used to assess the data base.
AFGL atmospheric absorption line parameters compilation - 1982 edition
The latest edition of the AFGL atmospheric absorption line parameters compilation for the seven most active infrared terrestrial absorbers is described. Major modifications to the atlas for this edition include updating of water-vapor parameters from 0 to 4300 per cm, improvements to line positions for carbon dioxide, substantial modifications to the ozone bands in the middle to far infrared, and improvements to the 7- and 2.3-micron bands of methane. The atlas now contains about 181,000 rotation and vibration-rotation transitions between 0 and 17,900 per cm. The sources of the absorption parameters are summarized.
AFGL trace gas compilation - 1982 version
The new edition of the AFGL trace gas compilation is described. The latest version provides the necessary parameters for the computation of absorption or emission spectra of major bands of twenty-one gases in the region from 0 to 10,000 per cm. Emphasis in this edition has been on the addition of numerous millimeter and submillimeter transitions, the inclusion of bands of significance in upper atmospheric processes, and strong IR bands of trace constituents likely to be used for remote detection. The sources for the additions and modifications of the absorption parameters are summarized.
Methane line parameters for the 2.3-micron region
A new compilation of methane line parameters for the 4136-4666-per cm region has been obtained using experimental positions and intensities combined with known quantum assignments from the literature. Positions and intensities measured directly from the observed spectrum by computer are reported with accuracies of + or - 0.0005 per cm and 2%, respectively, for single unblended absorptions.
The AFGL molecular line Atlases
There are two compilations: the main Atlas and the Trace Gas Atlas. The main Atlas includes the major absorbers in the Earth's atmosphere. The main Atlas includes about 150,000 lines (the Trace Gas Atlas is 30-40,000 at the moment). The information on each Atlas is essentially a card image per line, which includes the frequency (in vacuum wavenumbers) of the transition, the line strength at a standard temperature of 296 Kelvin, and the half width of the line.
Atlas of absorption lines from 0 to 17 900 cm(-1)
Plots of absorption line strength versus line position for wavenumbers from 0 to 17,900 cm(-1) are shown for 20 atmospheric gases (H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, NH3, HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, H2CO). Also shown are similar plots of lower-state energy values for adsorption lines for the strongly adsorbing atmospheric gases (H2O, CO2, O3, and CH4) for wavenumbers from 0 to 5000 cm(-1).
AFGL trace gas compilation - 1980 version
A new edition of the AFGL trace gas compilation is now available. Absorption line parameters of positions, intensities, and half-widths are given for the major bands of thirteen gases covering the spectral region from 0 to 10,000/cm. In addition to updating the original gases (NO, SO2, NO2, and NH3), the molecules HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, and H2CO have been added to the compilation. The sources for the additions and modifications are described.
Line parameters of methane from 2385 to 3200/cm
A list of new methane line parameters for the 2385-3200 cm region included in the Air Force Geophysical Laboratory's compilation of molecular line parameters is presented. Line positions were determined by computer computations from Fourier transform spectrometer data using a Kitt Peak subroutine. With the exception of class IV lines, all line strengths were determined by the method of equivalent widths. Additional line strengths were measured from spectra taken at cold sample temperatures so that lower state transition energies could be determined experimentally. Observed line positions and strengths are given for 8076 absorptions with strengths greater than 3.3 x 10 to the -24 cm/molecule.