| 1. |
- Gordon, I.E., et al.
(author)
-
The HITRAN2020 molecular spectroscopic database
- 2022
-
In: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier. - 0022-4073 .- 1879-1352. ; 277
-
Journal article (peer-reviewed)abstract
- The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years). All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules. The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition.
|
|
| 2. |
- Perrin, A., et al.
(author)
-
Molecular line parameters for the "MASTER" (Millimeter Wave Acquisitions for Stratosphere/Troposphere Exchange Research) database
- 2005
-
In: Journal of Atmospheric Chemistry. - : Springer Science and Business Media LLC. - 0167-7764 .- 1573-0662. ; 51:2, s. 161-205
-
Journal article (peer-reviewed)abstract
- In order to investigate the upper troposphere/lower stratosphere (UTLS) region of the earth's atmosphere, ESA/ESTEC (European space agency) is considering the opportunity to develop the spaceborne limb sounding millimeter sensor "MASTER" (millimeter wave acquisitions for stratosphere/troposphere exchange research). This instrument is part of the "atmospheric composition explorer for chemistry and climate interactions" (ACECHEM) project. In addition, ESA/ESTEC is developing the "MARSCHALS" (millimeter-wave airborne receiver for spectroscopic characterization of atmospheric limb sounding) airborne instrument which will demonstrate the feasibility of MASTER. The present paper describes the line-by-line database which was generated in order to meet at best the needs of the MASTER (or MARSCHALS) instrument. The linelist involves line positions, line intensities, line broadening and line shift parameters in the 294-305, 316-325, 342-348, 497-506 and 624-626 GHz spectral microwindows. This database was first generated for the target molecules for MASTER (H2O, O3, N2O, CO, O2, HNO3, HCl, ClO, CH3Cl, BrO). In addition, ten additional molecules (SO2, NO2, OCS, H2CO, HOCl, HCN, H2O2, COF2, HO2 and HOBr) had also to be considered in the database as "possible interfering species" for the retrieval of the target molecules of MASTER. The line parameters were derived, depending on their estimated accuracy, (i) from a combination of spectral parameters included in the JPL and HITRAN catalogs (ii) from data taken into the literature or (iii) using data obtained through experimental measurements (and/or) calculations performed during the present study.
|
|
| 3. |
- Verdes, C. L., et al.
(author)
-
A sensitivity study on spectroscopic parameter accuracies for a mm/sub-mm limb sounder instrument
- 2005
-
In: Journal of Molecular Spectroscopy. - : Elsevier BV. - 0022-2852 .- 1096-083X. ; 229:2, s. 266-275
-
Journal article (peer-reviewed)abstract
- The purpose of this paper is to perform a detailed error analysis for a mm/sub-mm limb sounding instrument with respect to spectroscopic parameters. This is done in order to give some insight into the most crucial spectroscopic parameters and to work out a list of recommendations for measurements that would yield the largest possible benefit for an accurate retrieval. The investigations cover a variety of spectroscopic line parameters, such as line intensity, line position, air and self broadening parameters and their temperature exponents, and pressure shift. The retrieval process is performed with the optimal estimation method (OEM). The OEM allows one to perform an assessment of the total statistical error, as well as of the model parameter error, such as the error coming from spectroscopic parameters. The instrument parameters assumed are those of the MASTER instrument studied by the European Space Agency, one of the candidate instruments for a future atmospheric chemistry mission. However, the same principle and method of analysis can be applied to any other millimeter/sub-millimeter limb sounding instrument, for instance the Japanese instrument JEM/SMILES, the Swedish instrument Odin, and the Earth Observing System Microwave Limb Sounder. We find that an uncertainty in the intensity of the strong lines give an error of similar magnitude on the retrieved species to which the lines belong. Uncertainties in the line position have overall a small impact on the retrieval, indicating that the line positions are known with sufficient accuracy. The air broadening parameters and their temperature exponents of a few strong lines dominate the error budget. On the other hand, the self broadening parameters and the pressure shifts are found to have a rather small impact on the retrieval.
|
|
| 4. |
- López-Puertas, M., et al.
(author)
-
Non-local thermodynamic equilibrium limb radiances for the mipas instrument on Envisat-1
- 1998
-
In: Journal of Quantitative Spectroscopy and Radiative Transfer. - 0022-4073 .- 1879-1352. ; 59:3-5, s. 377-403
-
Journal article (peer-reviewed)abstract
- An evaluation of the effects that the assumption of local thermodynamic equilibrium (LTE) has on the retrieval of pressure, temperature and the five primary target gases (O3, H2O, CH4, N2O, and HNO3) from spectra to be taken by Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on the Envisat-1 platform has been conducted. For doing so, non-LTE and LTE limb radiances in the spectral range of 680–2275 cm−1 (4.15–14.6 μm) with a resolution of 0.05 cm−1 at tangent heights from 10 to 70 km have been computed. These calculations included the most updated non-LTE populations of a large number of vibrational levels of the CO2, O3, H2O, CH4, N2O and HNO3 molecules which cause the most prominent atmospheric infrared emissions. A discussion of the most important non-LTE effects on the limb radiances as well as on the retrievals of pressure-temperature and volume mixing ratios of O3, H2O, CH4, N2O, and HNO3 is presented, together with the most important non-LTE issues that could be studied with the future coming of MIPAS data.
|
|
| 5. |
- López-Puertas, M., et al.
(author)
-
Non-LTE studies for the analysis of MIPAS/ENVISAT data
- 2002
-
In: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 4539, s. 381-395
-
Journal article (peer-reviewed)abstract
- The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a high-resolution limb sounder on board the European polar platform ENVISAT, scheduled for launch late in 2001. Three main characteristics converge in MIPAS which make it a very useful instrument for non-LTE studies: its wide spectral coverage (4.15-14.6 μm or 680-2275 cm-1); high spectral resolution (0.03 cm-1), and high sensitivity; all of this in addition to its global spatial coverage. In this paper we present an overview of the non-LTE studies that have been carried out in preparation for the analysis of MIPAS data, including the evaluation of non-LTE effects in the operational processing, focussed in the stratosphere, and the retrieval of species that normally emit under non-LTE conditions. The current mission plan for measuring the non-LTE upper atmosphere is described, as well as the general purpose non-LTE retrieval scheme developed for analyzing those measurements.
|
|
| 6. |
- Manuilova, R.O., et al.
(author)
-
Modelling of non-LTE limb spectra of i.r. ozone bands for the MIPAS space experiment
- 1998
-
In: Journal of Quantitative Spectroscopy and Radiative Transfer. - 0022-4073 .- 1879-1352. ; 59:3-5, s. 405-422
-
Journal article (peer-reviewed)abstract
- A new model for calculating the populations of the ozone vibrational states under non-LTE (Local Thermodynamic Equilibrium) conditions is presented. In the model, 23 vibrational levels of the O3 molecule, as well as three vibrational levels of the O2 molecule and two vibrational levels of the N2 molecule, are considered. The radiative transfer at the break-down of LTE was treated explicitly for 150 000 ro-vibrational transitions. The populations obtained were used to calculate limb radiances in various spectral regions of the 4.8 and 9.6 μm bands. Test retrievals of O3 vertical volume mixing ratio (VMR) profiles with a radiance model disregarding non-LTE were performed in order to assess the potential impact of non-LTE effects on the retrieval of the O3 abundances from MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) measurements.
|
|
| 7. |
- Perrin, A., et al.
(author)
-
Microwave and submillimeter-wave measurements of (HDCO)-C-12-O-16 in the nu(4), nu(5), and nu(6) bands : Evidence of vibrational induced rotational axis switching ("VIRAS")
- 2002
-
In: Journal of Molecular Spectroscopy. - : Elsevier BV. - 0022-2852 .- 1096-083X. ; 216:2, s. 214-224
-
Journal article (peer-reviewed)abstract
- The rotational spectrum of HDCO in the 4(1),5(1), and 6(1) excited vibrational states has been investigated in Lille and Kiel using a sample enriched in deuterium. In Lille, the measurements were performed in the millimeter region (100-600 GHz). The spectra in Kiel were recorded using Fourier transform microwave spectrometers in the regions around 8-18 and 18-20 GHz. employing a rectangular waveguide of length 12 m and a circular waveguide of length 36 m, respectively, These results Acre combined with the 4(1), 5(1), and 6(1) infrared energy levels which were obtained front a previous analysis of FTS spectra of the v(4) (CHD bend), v(5) (CHD rocking). and v(6) bands (out of plane bend) recorded in the 10-mum region at Giessen (A. Perrin, J,-M, Flaud, M. Smirnov, and M. Lock, J. Mol. Spectrosc. 203, 175-187 (2000)). The energy level calculation of the 4(1). 5(1), and 6(1) interacting states accounts for the usual A- and B-type Coriolis resonances in the 5(1) double left right arrow 6(1) and 4(1) double left right arrow 6(1) off diagonals blocks. In addition since the energy levels of the 5(1) and 6(1) states are very strongly resonating, it proved necessary. as ill our previous study. to Use a {J(x), J(z)} nonorthorhombic term in the 5(1) and 6(1) v-diagonal blocks of the Hamiltonian matrix in order to reproduce properly file observed microwave transitions and infrared energy levels. Therefore, this work confirms that HDCO is a good example of the vibrational induced rotational axis switching ("VIRAS") effect.
|
|
