Vassilii Nemtchinov

THE HITRAN MOLECULAR SPECTROSCOPIC DATABASE AND HAWKS (HITRAN ATMOSPHERIC WORKSTATION): 1996 EDITION

Since its first publication in 1973, the HITRAN molecular spectroscopic database has been recognized as the international standard for providing the necessary fundamental spectroscopic parameters for diverse atmospheric and laboratory transmission and radiance calculations. There have been periodic editions of HITRAN over the past decades as the database has been expanded and improved with respect to the molecular species and spectral range covered, the number of parameters included, and the accuracy of this information. The 1996 edition not only includes the customary line-by-line transition parameters familiar to HITRAN users, but also cross-section data, aerosol indices of refraction, software to filter and manipulate the data, and documentation. This paper describes the data and features that have been added or replaced since the previous edition of HITRAN. We also cite instances of critical data that are forthcoming.

The HITRAN molecular spectroscopic database: edition of 2000 including updates through 2001

This paper describes the status circa 2001, of the HITRAN compilation that comprises the public edition available through 2001. The HITRAN compilation consists of several components useful for radiative transfer calculation codes: high-resolution spectroscopic parameters of molecules in the gas phase, absorption cross-sections for molecules with very dense spectral features, aerosol refractive indices, ultraviolet line-by-line parameters and absorption cross-sections, and associated database management software. The line-by-line portion of the database contains spectroscopic parameters for 38 molecules and their isotopologues and isotopomers suitable for calculating atmospheric transmission and radiance properties. Many more molecular species are presented in the infrared cross-section data than in the previous edition, especially the chlorofluorocarbons and their replacement gases. There is now sufficient representation so that quasi-quantitative simulations can be obtained with the standard radiance codes. In addition to the description and justification of new or modified data that have been incorporated since the last edition of HITRAN (1996), future modifications are indicated for cases considered to have a significant impact on remote-sensing experiments

The HITRAN molecular spectroscopic database and HAWKS (HITRAN atmospheric workstation)

Nineteen ninety-eight marks the 25th anniversary of the release of the first HITRAN database. HITRAN is recognized as the international standard of the fundamental spectroscopic parameters for diverse atmospheric and laboratory transmission and radiance calculations. There have been periodic editions of HITRAN over the past decades as the database has been expanded and improved with respect to the molecular species and spectral range covered, the number of parameters included, and the accuracy of this information. The 1996 edition not only includes the customary line-by-line transition parameters familiar to HITRAN users, but also cross-section data, aerosol indices of refraction, software to filter and manipulate the data, and documentation. This paper describes the data and features that have been added or replaced since the previous edition of HITRAN. We also cite instances of critical data that is forthcoming. A new release is planned for 1998.

The 1997 spectroscopic GEISA databank

The current version GEISA-97 of the computer-accessible database system GEISA (Gestion et Etude des Informations Spectroscopiques Atmospheriques: Management and Study of Atmospheric Spectroscopic Information) is described. This catalogue contains 1,346,266 entries. These are spectroscopic parameters required to describe adequately the individual spectral lines belonging to 42 molecules (96 isotopic species) and located between 0 and 22,656 cm-1. The featured molecules are of interest in studies of the terrestrial as well as the other planetary atmospheres, especially those of the Giant Planets. GEISA-97 contains also a catalog of absorption cross-sections of molecules such as chlorofluorocarbons which exhibit unresolvable spectra. The modifications and improvements made to the earlier edition (GEISA-92) and the data management software are described. GEISA-97 and the associated management software are accessible from the ARA/LMD (Laboratoire de Meteorologie Dynamique du CNRS, France) web site: http://ara01.polytechnique.fr/registration.

NH3 and PH3 Line Parameters: The 2000 HITRAN Update and New Results

This paper describes the improvements incorporated into the 2000 version of the HITRAN database for ammonia (NH_3), as well as newer results for phosphine (PH_3) not included in HITRAN 2000. For ammonia, the HITRAN 2000 database contains some 29084 ammonia lines, more than double the number of lines in HITRAN 1996. Specifically, the 2000 update involved replacing pure-rotational and infrared transitions from 0 to 3700 cm^(-1) with new calculations for the ^(14)NH_3 isotopomer, whereas in the 4000 to 5000 cm^(-1) region, parameters from the 1996 database were retained. The rotational quantum number range for line positions, intensities and line broadening parameters updated in this new HITRAN version goes up to J=22, 15, 13 and 10 in the 8–1000 μm, 5 μm, 4 μm and 2.8–3.3 μm spectral regions respectively. For phosphine, a new database from 770 to 2156 cm^(-1) available for future updates is described and contrasted with parameters in HITRAN 2000.

Thermal infrared absorption coefficients of CFC-12 at atmospheric conditions

Abstract Spectral absorption coefficients k v (cm -1 atm -1 ) have been measured in the 9 and 11 μm bands of CFC-12 (CF 2 Cl 2 ) using a high-resolution Fourier transform spectrometer. Temperature and total (broadening) pressure have been varied to obtain results at conditions representative of tropospheric and stratospheric layers of the atmosphere. The measured absolute intensities (in units of 10 -17 cm.molecule -1 ) of the 9 and 11 μm bands are 7.595 ±0.070 and 5.750 ±0.068, respectively.

Measurements of line intensities and half-widths in the 10-μm bands of 14NH3

Abstract We present measurements of the absolute intensities and collision-broadened half-widths of spectral lines in the 10 μm bands of 14 NH 3 . H2-broadened, N2-broadened, and O2-broadened half-widths of lines aP(6,5)–aR(8,8) have been measured at 200, 255, and 296 K . Air-broadened and self-broadened half-widths are presented at 296 K . The variation of linewidths with the temperature and with the rotational quantum numbers J and K is examined. A polynomial function of m and K which fits the observed linewidths accurately is presented.

Spectral absorption-coefficient data on HCFC-22 and SF6 for remote-sensing applications

Abstract Spectral absorption-coefficients (cross-sections) kv (cm-1atm-1) have been measured in the 7.62, 8.97, and 12.3 μm bands of HCFC-22 (CHCIF2) and the 10.6 μm bands of SF6 employing a high-resolution Fourier-transform spectrometer. Temperature and total pressure have been varied to simulate conditions corresponding to tropospheric and stratospheric layers in the atmosphere. The kv are compared with values measured by us previously using a tunable diode laser spectrometer and with the appropriate entries in HITRAN and GEISA, two of the databases known to the atmospheric scientist. The measured absolute intensities of the bands are compared woth previously published values.

Measurements of line intensities and line widths in the ν3-fundamental band of nitrous oxide at atmospheric temperatures

Abstract We present measurements of the absolute intensities, N2-, O2-, and air-broadened half-widths of spectral lines in the 4.5 μm (ν3-fundamental) band of 14 N 2 16 O at 216, 250 and 296 K . These data were obtained using a high-resolution ( 0.002 cm −1 ) Fourier-transform spectrometer. The variation of the line widths with temperature and the rotational quantum number m (|m| is J in the P-branch and J+1 in the R-branch, with J being the rotational quantum number of a linear molecule) is examined. Simple empirical polynomial (quartic) fits of the measured half-widths are presented. A new improved method of extrapolation of line-width data to higher values of m has also been devised.

Thermal infrared absorption cross-sections of CCl4 needed for atmospheric remote sensing

Abstract Highly accurate spectral absorption cross-sections k ν ( cm 2 molecule −1 ) were measured in the 12.7 μm band of CCl4 at temperatures between 208 and 296 K and pressures between 10 and 1013 mb with a high-resolution Fourier-transform spectrometer. Our data were obtained at pressures p and temperatures T that characterize the atmospheric layers in the commonly adapted models of the atmosphere. The selected (p,T) combinations also represent tangent heights in solar-occultation-type remote sensing observations and actual conditions recorded by balloon-borne instruments in the Arctic. The combined absolute intensity (or integrated cross-section) of the bands contributing to the absorption around 12.7 μm is 6.295±0.102×10 −17 cm molecule −1 .