An empirical line list for methane near 1µm (9028–10,435cm−1)

Béguier, S.; Liu, A.W.; Campargue, A.

doi:10.1016/j.jqsrt.2015.07.003

Cited by 22 publications

(10 citation statements)

References 45 publications

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“…The code has been validated against a number of analytic results and previous radiative-convective calculations. Further details of our CIA and line-by-line climate calculations are given in the Auxiliary Online Material [Cherepanov et al, 2016;Boys and Bernardi, 1970;Knizia et al, 2009;Cohen and Roothaan, 1965;Clough et al, 1992;Rothman et al, 2013;Murphy and Koop, 2005;Gruszka and Borysow , 1997;Baranov et al, 2004;Wordsworth et al, 2010;Pierrehumbert, 2011;Hansen and Travis, 1974;Claire et al, 2012;Béguier et al, 2015;Goldblatt et al, 2013;Schaefer et al, 2016].…”

Section: Methodsmentioning

confidence: 99%

Transient reducing greenhouse warming on early Mars

Wordsworth

Kalugina

Lokshtanov

et al. 2017

Geophysical Research Letters

220

324

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The evidence for abundant liquid water on early Mars despite the faint young Sun is a long‐standing problem in planetary research. Here we present new ab initio spectroscopic and line‐by‐line climate calculations of the warming potential of reduced atmospheres on early Mars. We show that the strength of both CO2–H2 and CO2–CH4 collision‐induced absorption (CIA) has previously been significantly underestimated. Contrary to previous expectations, methane could have acted as a powerful greenhouse gas on early Mars due to CO2–CH4 CIA in the critical 250–500 cm−1 spectral window region. In atmospheres of 0.5 bar CO2 or more, percent levels of H2 or CH4 raise annual mean surface temperatures by tens of degrees, with temperatures reaching 273 K for pressures of 1.25–2 bars and 2–10% of H2 and CH4. Methane and hydrogen produced following aqueous alteration of Mars' crust could have combined with volcanically outgassed CO2 to form transient atmospheres of this composition 4.5–3.5 Ga. Our results also suggest that inhabited exoplanets could retain surface liquid water at significant distances from their host stars.

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Section: Methodsmentioning

confidence: 99%

Transient reducing greenhouse warming on early Mars

Wordsworth

Kalugina

Lokshtanov

et al. 2017

Geophysical Research Letters

220

324

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“…The HITRAN 2000 data set included methane lines up through the fourth polyad, or tetradecad ( 6 ), at approximately 6000 cm −1 ; HITRAN 2004 included new lines between 6180 and 9200 cm −1 ; whereas HITRAN 2008 added the fifth (icosad) and sixth (triacontad) polyads at ~7500 and 9000 cm −1 . The HITRAN 2012 data set added the eighth (pentacontakaipentad) polyad between 11,000 and 12,000 cm −1 while skipping the seventh (tetracontad) polyad spanning 10,000 cm −1 , although this missing polyad has subsequently been measured in the laboratory ( 31 ) and has been included in the 2016 HITRAN edition. As of this writing, the most recent HITRAN 2016 update ( 11 ) to CH 4 spectroscopy is still not fully implemented in the LBL code described below, and therefore, we have not included it in our calculations.…”

Section: Methodsmentioning

confidence: 99%

Large regional shortwave forcing by anthropogenic methane informed by Jovian observations

et al. 2018

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“…In this paper, we have recorded spectra of hot methane in the near-infrared region (5200-9200 cm −1 , 1.92 − 1.08 μm) that includes the tetradecad (6000 cm −1 , 1.6 μm), icosad (7500 cm −1 , 1.3 μm), and triacontad (8600 cm −1 , 1.1 μm) polyads. Previous measurements in this range have been recorded with cold or room-temperature samples; e.g., for the tetradecad (Nikitin et al , 2017a, icosad (Campargue et al 2012;Rey et al 2016b) and triacontad (Brown 2005;Béguier et al 2015) except for the recent paper (Ghysels et al 2018), reporting laser absorption experiments at T=1000 K in a limited interval near 1.7 μm, and the Fourier transform emission spectrum reported by Nassar & Bernath (2003). The most recent theoretical predictions in the near-infrared for hot methane are by Rey et al (2017) and Yurchenko et al (2017).…”

Section: Introductionmentioning

confidence: 99%

Atlas of Experimental and Theoretical High-temperature Methane Cross Sections from T = 295 to 1000 K in the Near-infrared

Wong

Bernath

Rey

et al. 2019

ApJS

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Spectra of hot methane were recorded using a tube furnace and a high-resolution Fourier transform spectrometer. We obtained experimental absorption spectra in the 1.85-1.11 μm near-infrared region at eight temperatures ranging from 295 K up to 1000 K. We have converted these into an atlas of absorption cross sections at each temperature for the methane tetradecad, icosad and triacontad polyads, excluding some spectral intervals either strongly contaminated by water or due to baseline fringes. On the theoretical side, the spectra were simulated from the ab initio-based Reims-Tomsk TheoReTS line list for the same experimental conditions. This line list has been constructed by global variational calculations from potential energy and dipole moment surfaces followed by empirical line position corrections deduced from previously published analyses. The comparisons showed very good overall agreement between observations and theory at high spectral resolution for the tetradecad and icosad and at medium or low resolution above this range. A full set of the theoretical absorption cross sections is also included. Detailed temperature dependence of the methane absorption enables the efficient method of remotely probing the temperature of distant astronomical objects based on a comparison of relative signals in carefully selected spectral intervals. This first combined experimental and theoretical easy-to-use cross-section library in the near-infrared should be of major interest for the interpretation of current and future astronomical observations up to a resolving power of 100,000-300,000 in the range 6400-7600 cm −1 and a resolving power of 5000-10,000 in the higher wavenumber range up to 9000 cm −1 .

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An empirical line list for methane near 1µm (9028–10,435cm−1)

Cited by 22 publications

References 45 publications

Transient reducing greenhouse warming on early Mars

Transient reducing greenhouse warming on early Mars

Large regional shortwave forcing by anthropogenic methane informed by Jovian observations

Atlas of Experimental and Theoretical High-temperature Methane Cross Sections from T = 295 to 1000 K in the Near-infrared

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