•New water vapor spectra broadened by CO2 recorded by FTS at room temperature in two spectral region: 2.7 and 6 µm.•Retrieval of line parameters with multispectrum fitting procedure.•Modified Complex ...Robert-Bonamy calculations.•New measurements and calculations of H2O broadened by CO2 line-shape parameters.
For decades, the remote sensing measurements have been made in planetary atmospheres in the Solar System and beyond. As the performance of the space instruments improves, the atmospheric science community is more and more in need of accurate spectroscopic data. The current databases offer some parameters for non-Earth atmospheres but are far from complete for all situations. For example, measured H2O line parameters in CO2-rich atmospheres such as Mars and Venus are missing while they are of prime importance to learn about the evolution of the atmospheres. New Fourier Transform Spectrometer spectra were recorded respectively around 2.7 and 6 µm, using a Connes’ type FT spectrometer built in Reims. The spectra were analysed using a multispectrum fitting procedure to obtain the line-shape parameters of H2O broadened by CO2. Modified Complex Robert-Bonamy calculations of the half-width, line shift, and their temperature dependence were made in the spectral region from 1300 to 5000 cm−1. The measurements and calculations are presented and compared with data available in the literature.
Total internal partition sums for the HITRAN2020 database Gamache, Robert R.; Vispoel, Bastien; Rey, Michaël ...
Journal of Quantitative Spectroscopy & Radiative Transfer/Journal of quantitative spectroscopy & radiative transfer,
September 2021, 2021-09-00, 2021-09, Volume:
271
Journal Article
Peer reviewed
Open access
•Total internal partition sums (TIPS) are reported for 178 isotopologues of 57 molecules important in planetary atmospheres.•TIPS are reported from 1 K to a Tmax that insures the TIPS have ...converged.•The new versions of the TIPS code are available in both FORTRAN and python languages.
Total internal partition sums (TIPS) are reported for the 181 isotopologues of 57 molecules important in planetary atmospheres. Molecules 1 to 55, with the exception of #34 atomic oxygen, are taken from the HITRAN2020 list, and for some molecules additional isotopologues are considered. Molecules 56 and 57 are C3H4, CH3, respectively. New to TIPS are the calculations for 12CH4, 13CH4, 12CH3D, 13CH3D, 14N16O, 15N16O, 14N18O, 16O32S18O, 33S16O2, 15N16O2, 18OH, 16OD, 35Cl16O, 37Cl16O, 16O13C34S, 32S19F6, 12C2H5D, 12C2H3D, 12C19F4, 12CH319F, 70GeH4, 72GeH4, 73GeH4, 74GeH4, 76GeH4, 12CH3127I, 13CH3127I, and 14N19F3. In addition, all the molecules/isotopologues that were not recalculated for TIPS2017 (Gamache et al., JQSRT 203, 70, 2017) have been recalculated using the 2014 CODATA physical constants. The TIPS are determined by various methods, generally from 1 to 5000 K. These data are provided with HITRAN2020 and a new version of the TIPS code is available in both FORTRAN and python languages.
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Laboratory spectroscopic data is essential for the modeling of hot exoplanet atmospheres, since molecules such as methane, a major component of hot-Jupiter-type exoplanet atmospheres, have a complex ...vibrational energy structure that makes computational predictions difficult at high temperatures for ro-vibrational transitions involving highly excited vibrational sates. To better inform line lists used in radiative transfer modeling, the ro-vibrational spectrum of methane has been recorded in the tetradecad region between 1.7 and 1.65 μm (5880–6060 cm−1) through non-local thermodynamic equilibrium (non-LTE) cavity ringdown spectroscopy (CRDS). Non-LTE conditions, characterized by a low rotational temperature (∼39 K) and a high vibrational temperature (up to 1130 K), have been obtained by hypersonic expansion of a pre-heated mixture of argon and methane in a contoured Laval nozzle. The high vibrational temperature increases the intensity of new hot bands, while the very low rotational temperature greatly simplifies their rotational structure, thus facilitating their identification. A close comparison of the recorded CRDS data to the TheoReTS database reveals both inefficient vibrational relaxation between polyads and efficient vibrational relaxation between vibrational states forming a polyad. These effects result in an overpopulation of the lowest vibrational energy level of each polyad, an effect not widely currently incorporated in non-LTE radiative transfer models. A series of new hot band transitions originating from the pentad and octad polyads were assigned and are provided as a line list for use in future databases.
•Vibrationally hot and rotationally cold infrared spectra of CH4.•Simulation of the non-LTE spectrum of CH4 based on the TheoReTS database.•Temperature retrieval method of non-LTE methane spectra.•Ro-vibrational relaxation process of methane in a hypersonic jet.•Newly assigned hot band transitions from octad and pentad polyads.
•New water vapor spectra broadened by CO2 recorded with a Bruker IFS 125 HR at room temperature in 2.7 µm spectral region.•Retrieval of line parameters with multispectrum fitting procedure.•Use of ...different beyond-Voigt line profiles (Rautian, quadratic speed-dependent Voigt, quadratic speed-dependent Rautian).•Comparison of line collisional parameters with literature.
H2O is an important molecule in the quest to better understand the evolution of solar system. In the study of Venus and Mars CO2-rich atmospheres (around 96 % of their composition) and because of the space instruments constant improvements, the planetary community needs spectroscopic data as accurate as possible.
Continuing from our previous study JQSRT 231, 126(2019), new spectra of H2O perturbed by CO2 were measured with our new experimental set-up in the 2.7 µm region to compare with the previous results. After the improvement in the determination of the partial pressure of water vapor, the line parameters were then determined with a multispectrum fitting procedure using a Voigt profile in the same way as in JQSRT 231, 126(2019). This led to characteristic W-shape residuals that have been improved using beyond-Voigt profiles. Our investigation showed that considering the speed dependence of collisional line parameters is essential to obtain better line-shape parameters in the considered experimental conditions.
•Ab initio quantum scattering calculations.•Temperature dependences of the pressure broadening, pressure shift, speed dependence and the complex Dicke parameter.•Comparison of the ...four-temperature-ranges (4TR) and double-power-law (DPL) temperature dependence models.•Hartmann-Tran profile (HTP) parameterization.
Temperature dependences of molecular line-shape parameters are important for the spectroscopic studies of the atmospheres of the Earth and other planets. A number of analytical functions have been proposed as candidates that may approximate the actual temperature dependences of the line-shape parameters. In this article, we use our ab initio collisional line-shape calculations for several molecular systems to compare the four temperature ranges (4TR) representation, adopted in the HITRAN database J. Quant. Spectrosc. Radiat. Transfer 2017;203:3 in 2016, with the double-power-law (DPL) representation. Besides the collisional broadening and shift parameters, we consider also the most important line-shape parameters beyond Voigt, i.e., the speed dependence of broadening and shift parameters, and real and imaginary parts of the complex Dicke parameter. We demonstrate that DPL gives better overall approximation of the temperature dependencies than 4TR. It should be emphasized that DPL requires fewer parameters and its structure is much simpler and more self-consistent than the structure of 4TR. We recommend the usage of DPL representation in HITRAN, and present DPL parametrization for Voigt and beyond-Voigt line profiles that will be adopted in the HITRAN database. We also discuss the problem of the Hartmann-Tran profile parametrization in which the correlation parameter, η, and frequency of the velocity-changing collisions parameter, νvc, diverges to infinity when collisional shift crosses zero; we recommend a simple solution for this problem.
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•GEISA-2020 database release: 6,746,987 entries in the line parameters database.•23 molecules updated and 6 new molecules added (HONO, COFCl, CH3F, CH3I, RuO4, H2C3H2 (isomer of ...C3H4).•Evaluation of the spectroscopic parameters through radiative transfer simulations compared to atmospheric spectra (SPARTE chain).
This paper describes the 2020 release of the GEISA database (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information), developed and maintained at LMD since 1974. GEISA is the reference database for several current or planned Thermal and Short-Wave InfraRed (TIR and SWIR) space missions IASI (Infrared Atmospheric Sounding Interferometer), IASI-NG (IASI New Generation), MicroCarb (Carbon Dioxide Monitoring Mission), Merlin (MEthane Remote sensing LIdar missioN). It is actually a compilation of three databases: the “line parameters database”, the “cross-section sub-database” and the “microphysical and optical properties of atmospheric aerosols sub-database”. The new edition concerns only the line parameters dataset, with significant updates and additions implemented using the best available spectroscopic data.
The GEISA-2020 line parameters database involves 58 molecules (145 isotopic species) and contains 6,746,987 entries, in the spectral range from 10−6 to 35877 cm−1. In this version, 23 molecules have been updated (with 10 new isotopic species) and 6 new molecules have been added (HONO, COFCl, CH3F, CH3I, RuO4, H2C3H2 (isomer of C3H4)) corresponding to 15 isotopic species. The compilation can be accessed through the AERIS data and services center for the atmosphere website (https://geisa.aeris-data.fr/), with the development of a powerful graphical tool and convenient searching, filtering, and plotting of data using modern technologies (PostgreSQL database, REST API, VueJS, Plotly).
Based on four examples (H2O, O3, O2 and SF6), this paper also shows how the LMD in house validation algorithm SPARTE (Spectroscopic Parameters And Radiative Transfer Evaluation) helps to evaluate, correct, reject or defer the input of new spectroscopic data into GEISA and this, thanks to iterations with researchers from different communities (spectroscopy, radiative transfer).
•First measurement of SD ЫВ broadening and shifting of the 183-GHz water line for self- and air-broadening, and their temperature dependences.•MCRB calculations of the line shape parameters, their ...temperature and speed-dependence over the range of 200–3000 K agree with measurements.•The impact of the updated spectroscopic parameters on radiative-transfer calculations and atmospheric water-vapor retrievals is calculated.•Consideration of speed-dependence is necessary for accurate atmospheric water vapor profile retrieval with the 183-GHz line.
The water vapor line at 183 GHz was studied over the temperature range of 219–358 K using a spectrometer with radioacoustic detection of absorption, providing a signal-to-noise ratio of up to 8000. The study includes the first measurement of speed-dependent collisional broadening and shifting of this line for both self- and air-broadening, and their temperature dependences. The sign of self-shifting changes at about 280 K. Line-shape parameters are obtained for Voigt and quadratic speed-dependent Voigt shape factors. Temperature dependences of the line parameters are analyzed using empirical models from the literature. Theoretical Modified Complex Robert–Bonamy calculations of the line shape parameters, their temperature and speed-dependence are made over the temperature range of 200–3000 K. The measurements and calculations show very good agreement, although with some discrepancies for line shift parameters. The impact of the newly-measured line parameters on atmospheric water-vapor estimation from ground-based and satellite instruments is evaluated by simulation of downwelling and upwelling brightness temperatures and retrieved water-vapor mixing ratio, for atmospheric conditions typical of six climate zones. For the case of ground-based or limb-scanning radiometry with a background of cold space, the impact of speed-dependence is comparable to or exceeds that of measurement error and will introduce systematic errors if neglected. Therefore, consideration of speed-dependence is necessary for accurate estimation of water vapor with this line. The impact on upwelling brightness temperature is smaller.
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