GOSAT-2014 methane spectral line list

doi:10.1016/j.jqsrt.2014.12.003

Elsevier

Journal of Quantitative Spectroscopy and Radiative Transfer

Volume 154, March 2015, Pages 63-71

Journal of Quantitative Spectroscopy and Radiative Transfer

https://doi.org/10.1016/j.jqsrt.201412003 Get rights and content

Highlights

•
The upgrade of the GOSAT methane line list in the 5550–6240 cm⁻¹ region is done.
•
12,146 experimental methane line positions and intensities are retrieved.
•
6376 lower energy levels for methane lines are determined.

Abstract

The updated methane spectral line list GOSAT-2014 for the 5550–6240 cm⁻¹ region with the intensity cutoff of ×ばつ10^–25 cm/molecule at 296 K is presented. The line list is based on the extensive measurements of the methane spectral line parameters performed at different temperatures and pressures of methane without and with buffer gases N₂, O₂ and air. It contains the following spectral line parameters of about 12150 transitions: line position, line intensity, energy of lower state, air-induced and self-pressure-induced broadening and shift coefficients and temperature exponent of air-broadening coefficient. The accuracy of the line positions and intensities are considerably improved in comparison with the previous version GOSAT-2009. The improvement of the line list is done mainly due to the involving to the line position and intensity retrieval of six new spectra recorded with short path way (8.75 cm). The air-broadening and air-shift coefficients for the J-manifolds of the 2ν₃(F₂) band are refitted using the new more precise values of the line positions and intensities. The line assignment is considerably extended. The lower state J-value was assigned to 6397 lines representing 94.4% of integrated intensity of the considering wavenumber region. The complete assignment was done for 2750 lines.

Introduction

Methane (CH₄) is one of the important anthropogenic greenhouse gases. Nowadays many groups in the world are performing the continuous monitoring of several greenhouse gases including methane in the Earth׳s atmosphere. For these purposes, the Japanese Greenhouse gases Observing SATellite (GOSAT) jointly developed by the Japanese Ministry of the Environment (MOE), Japan Aerospace Exploration Agency (JAXA), and National Institute for Environmental Studies (NIES), the world׳s first satellite to measure the column amounts and profiles of the concentration of carbon dioxide and methane over the globe from space, has been in operation since the early 2009. Observational results have been published in Refs. [1], [2]. MOE, JAXA, NIES also started the development of GOSAT-2 in 2013. GOSAT-2 will be launched in 2017–2018 [3], [4].

The strongest absorption band 2ν₃(F₂) of CH₄ at 1.67 μm has been chosen to retrieve the CH₄ column amount from short wavelength infrared spectra observed with the Thermal And Near-infrared Sensor for carbon Observation-Fourier Transform Spectrometer (TANSO-FTS) on board the GOSAT [2]. To provide the retrieval algorithms with the methane spectral line parameters we elaborated the GOSAT-2009 methane line list [5]. This line list is based on the spectra of pure CH₄ and of the mixtures of methane with N₂, O₂ and air buffer gases. The spectra were recorded in the 5550–6240 cm⁻¹ spectral range using Bruker IFS 120 HR and 125 HR high resolution Fourier transform spectrometers at the Toray Research Center Inc. [6], [7], [8]. Voigt profile was used as line shape function in retrieving the CH₄ spectral line parameters. The line assignment was based on the results of the global modeling of the CH₄ energy levels in the tetradecad region within the framework of the method of effective operators (see Ref. [9] for details). But we have managed to assign only one-third of the observed lines. By means of the "two temperature (2 T) method," the additional assignments of lower J values for the observed lines have been done leading in total to 44% lines with known lower energies.

Since the time of publication of the GOSAT-2009 methane line list several investigations of the methane spectra in the 1.67 μm region have been performed. Gao et al. [10] and Campargue et al. [11] using differential absorption spectroscopy have recorded methane spectra at liquid nitrogen and at room temperatures. From these spectra they have developed the methane line dataset WKLMC in the 5852–6183 cm⁻¹ region [12]. Compared to the GOSAT-2009 line list this new line dataset includes a larger number of entries because the sensitivity of the measurements performed in Refs. [10], [11] is two orders of magnitude higher. More empirical lower state energies obtained by means of "two temperature (2 T) method" are presented in WKLMC than in GOSAT-2009. Zolot et al. [13] have measured line positions and intensities of the CH₄ lines in the region of 2ν₃(F₂) band using dual comb spectroscopy. The uncertainties in the determination of the line position in their case are very small (vary from .5 to 1.2 MHz). Finally, Nikitin et al. [9] have published the results of new global fit of all assigned lines of ¹²CH₄ in the 0–6200 cm⁻¹region. This allowed extending of the line assignment in our spectra.

The HITRAN-2012 methane line list [14] in the region of 5550–6240 cm⁻¹ was formed using WKLMC line list [12], GOSAT line list [5] and experimental data from Ref. [13] (see Ref. [15] for details).

In addition to the reasons mentioned above there are several other reasons that forced us to upgrade the GOSAT line list. First of all we now more precisely derived some of the line positions in the 2ν₃(F₂) J-manifold using the observed line positions in the hot 2ν₃(F₂)-ν₄ band [16]. In both Refs. [11], [13] it is mentioned that the line intensities in the 2ν₃(F₂) J-manifolds published in our previous work [5] are overestimated on about 5%. In addition only small and medium J values were assigned in our paper [5] because the existing set of effective Hamiltonian parameters did not allow making of precise predictions of the positions for the lines with high J-values. The improved set of the effective Hamiltonian parameters [9] and new potential energy and dipole moment surfaces [17], [18] give a variational prediction [19] of the line positions and intensities for the high J-values with considerably better accuracy than it was earlier. Owing to this fact we have managed to assign a number of new lines with J between 10 and 14. We also extended the number of lines with partial assignment (energy of lower state).

Compared to the methane line lists from Refs. [12], [13] GOSAT line list contains in addition broadening and shift parameters. As it has been discussed in our previous paper [5] and by Frankenberg et al. [20] the correlation between retrieved line parameters in cases of the unresolved 2ν₃(F₂) J-manifolds is very large. To have consistency between broadening and shift parameters from one side and line positions and intensities from the other side we use our own set of line parameters in the GOSAT-2014 and do not include into this line list the new measured line positions and intensities from Refs. [12], [13].

Section snippets

Experiment

The upgrade of the GOSAT methane line list was done on the basis of the same experimental data which are described in our preceding paper [5] but six additional spectra were involved in the present analysis. The used experimental conditions are listed in Table 1. The experimental conditions for six additional spectra are printed in italics in this table.

The spectra were recorded using Bruker IFS 120 HR and 125 HR high resolution Fourier transform spectrometers at the Toray Research Center Inc.

Spectra assignment

The line assignment is based mainly on the results of the new global modeling of the CH₄ energy levels in the tetradecad region within the framework of the method of effective operators [9]. The main part of the newly assigned lines has J values from 9 to 14. For the assignment of the lines of ¹³CH₄ isotopologue the spectrum of ¹³C-enriched methane sample (99.3% purity, ISOTEC) was used [8]. This spectrum was recorded with 8.75 cm absorption path length cell at room temperature and pressure of 15

Line positions and line intensities

The line positions and intensities were newly determined in this paper using all spectra of pure methane presented in Table 1. In comparison with the GOSAT-2009 line list, six new spectra were involved for the retrieval of the line positions and intensities (spectra 39, 40, 43, 44, 47 and 48 in Table 1). The spectral line parameters were determined with the SpectraPlot computer code [21], in which a nonlinear least-squares method is applied to the simultaneous fitting of the spectra recorded

Broadening and shift parameters

The majority of the lines in the GOSAT-2014 line list have the broadening and shift coefficients obtained from the results published by Lyulin et al. [6], [7]. The air-broadening (

γ_{a i r}

) and self-broadening (

γ_{s e l f}

) coefficients in cm⁻¹atm⁻¹ at 296 K were calculated using the following empirical equations proposed in the papers cited above:

γ_{a i r} = 0.0631 + 0.00152 | m | - 0.000218 | m |^{2},

γ_{s e l f} = 0.0803 + 0.000243 | m | - 0.000115 | m |^{2},

where

| m |

is the rotational label (

| m | = J

for P and Q-branches, and

| m | = J + 1

for

GOSAT-2014 line list

The new version of the GOSAT line list is given in electronic form as Supplementary Material to this paper. It includes 12,146 lines, 53% of which are assigned as the lines of two methane isotopologues ¹²CH₄ (6070 lines) and ¹³CH₄ (327 lines). The GOSAT-2014 line list contains more assigned lines than the GOSAT-2009 line list (44%). The line intensities are given with the "natural" isotopic abundances adopted for the HITRAN database [14]. We assume that the majority of the unassigned lines

Discussion and conclusion

In this paper we present the updated methane spectral line list GOSAT-2014 in the 5550–6240 cm⁻¹ region with the intensity cutoff of ×ばつ10^–25 cm/molecule at 296 K. The improvement of the line list compared to the GOSAT-2009 line list is done mainly due to the involving of the line position and intensity retrievals of six new spectra recorded with short path way (8.75 cm). The majority of newly retrieved line intensities for the strongest lines are in good agreement with those published in Refs. [12]

Acknowledgments

AVN thanks the computer centers of ICM@MG SB RAS (Novosibirsk) and SKIF Siberia (Tomsk). We thank Alain Campargue for pointing out the several lines in our line list with the problem values of the line parameters.

References (23)

A.V. Nikitin et al.
GOSAT-2009 methane spectral line list in the 5550–6236 cm⁻¹ range
J Quant Spectrosc Radiat Transfer
(2010)
O.M. Lyulin et al.
Measurements of N₂- and O₂-broadening and shifting parameters of methane spectral lines in the 5550–6236 cm⁻¹ region
J Quant Spectrosc Radiat Transfer
(2009)
O.M. Lyulin et al.
Measurements of self-broadening and self-pressure-induced shift parameters of the methane spectral lines in the 5556–6166 cm⁻¹ range
J Quant Spectrosc Radiat Transfer
(2011)
A.V. Nikitin et al.
Isotopic substitution shifts in methane and vibrational band assignment in the 5560–6200 cm⁻¹ region
J Quant Spectrosc Radiat Transfer
(2009)
B. Gao et al.
Empirical low energy values for methane transitions in the 5852–6181 cm⁻¹ region by absorption spectroscopy at 81 K
J Mol Spectrosc
(2009)
A. Campargue et al.
An improved empirical line list for methane in the region of the 2ν₃ band at 1.66 μm
J Quant Spectrosc Radiat Transfer
(2013)
A. Campargue et al.
The WKLMC empirical line lists (5852–7919 cm⁻¹) for methane between 80 K and 296 K: final lists for atmospheric and planetary applications
J Mol Spectrosc
(2013)
L.S. Rothman et al.
The HITRAN2012 molecular spectroscopic database
J Quant Spectrosc Radiat Transfer
(2013)
L.R. Brown et al.
Methane line parameters in the HITRAN2012 database
J Quant Spectrosc Radiat Transfer
(2013)
A.V. Nikitin et al.
Preliminary assignments of 2ν₃–ν₄ hot band of ¹²CH₄ in the 2 μm transparency window from long-path FTS spectra
J Mol Spectrosc
(2011)

A.V. Nikitin et al.

Rotational and vibrational energy levels of methane calculated from a new potential energy surface

Chem Phys Lett

(2011)

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GOSAT-2014 methane spectral line list

Highlights

Abstract

Introduction

Section snippets

Experiment

Spectra assignment

Line positions and line intensities

Broadening and shift parameters

GOSAT-2014 line list

Discussion and conclusion

Acknowledgments

J Quant Spectrosc Radiat Transfer

J Quant Spectrosc Radiat Transfer

J Quant Spectrosc Radiat Transfer

J Quant Spectrosc Radiat Transfer

J Mol Spectrosc

J Quant Spectrosc Radiat Transfer

J Mol Spectrosc

J Quant Spectrosc Radiat Transfer

J Quant Spectrosc Radiat Transfer

J Mol Spectrosc

Chem Phys Lett