High resolution FTIR spectroscopy of CFC's in a supersonic jet expansion

McNaughton, Don; McGilvery, D. C.; Robertson, Evan G.

doi:10.1016/0022-2860(95)08574-f

Cited by 11 publications

(17 citation statements)

References 11 publications

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“…The spectroscopic uncertainty of this data has been estimated in the literature to be 5 % (Rothman et al, 1998;Rinsland et al, 2005), however the spectral resolution (0.03 cm −1 and 0.01 cm −1 at pressures below 40 Torr, which corresponds to 53.3 hPa) of the laboratory data may introduce small systematic errors, together with the interpolation to different temperatures and pressures. Indeed, CFC-11 and CFC-12 show dense and sharp spectral structure at very high spectral resolution, even in the Q-branches (see, e.g., Orphal, 1991;McNaughton et al, 1994McNaughton et al, , 1995D'Amico et al, 2002). It is also important to note that comparisons of the absolute band intensities (see, e.g., Varanasi and Nemtchinov, 1994;D'Amico et al, 2002) with other studies show larger differences.…”

Section: Cfc Retrievalsmentioning

confidence: 87%

Global CFC-11 (CCl₃F) and CFC-12 (CCl₂F₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

et al. 2012

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Abstract. Vertical profiles of CFC-11 (CCl3F) and CFC-12 (CCl2F2) have been measured with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) with global coverage under daytime and nighttime conditions. The profile retrieval is based on constrained nonlinear least squares fitting of measured limb spectral radiance to modeled spectra. CFC-11 is measured in its ν4-band at 850 cm−1, and CFC-12 is analyzed in its ν6-band at 922 cm−1. To stabilize the retrievals, a Tikhonov-type smoothing constraint is applied. Main retrieval error sources are measurement noise and elevation pointing uncertainties. The estimated CFC-11 retrieval errors including noise and parameter errors but excluding spectroscopic data uncertainties are below 10 pptv in the middle stratosphere, depending on altitude, the MIPAS measurement mode and the actual atmospheric situation. For CFC-12 the total retrieval errors are below 28 pptv at an altitude resolution varying from 3 to 5 km. Time series of altitude/latitude bins were fitted by a simple parametric approach including constant and linear terms, a quasi-biennial oscillation (QBO) proxy and sine and cosine terms of several periods. In the time series from 2002 to 2011, quasi-biennial and annual oscillations are clearly visible. A decrease of stratospheric CFC mixing ratios in response to the Montreal Protocol is observed for most altitudes and latitudes. However, the trends differ from the trends measured in the troposphere, they are even positive at some latitudes and altitudes, and can in some cases only be explained by decadal changes in atmospheric age of air spectra or vertical mixing patterns.

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Section: Cfc Retrievalsmentioning

confidence: 87%

Global CFC-11 (CCl₃F) and CFC-12 (CCl₂F₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

et al. 2012

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“…An integration region of 855-900 cm À1 for n 3 + n 7 and 900-950 cm À1 for n 6 was used, following ref. 25. Fig.…”

Section: Discussion Of the Fermi Resonance Between N 3 + N 7 And Nmentioning

confidence: 99%

“…Giorgianni et al24 obtained effective molecular constants for the n 1 band from an analysis of diode laser spectra recorded at 200 K with a resolution of about 0.002 cm À1 . McNaughton et al25 used a FTIR apparatus coupled to a supersonic jet expansion to obtain spectra at approximately 40 K, with a spectral resolution of 0.0034 cm À1 , and analyzed the n 1 fundamental of CF 2 35 Cl 2 . The n 8 band has been analyzed for CF 2 35 Cl 2 and CF 2 35 Cl 37 Cl by McNaughton et al 26 using data from FTIR jet spectra.…”

mentioning

confidence: 99%

Analysis of the ν3 + ν7 combination band of CF2Cl2 from spectra obtained by high resolution diode laser and FTIR supersonic jet techniquesElectronic supplementary information (ESI) available: line assignments for diode laser spectra for transitions ν3 and ν7 of CF235Cl2 (Table S1) and CF235Cl37Cl (Table S2). See http://www.rsc.org/suppdata/cp/b1/b110919g/

D'Amico

Snels

Hollenstein

et al. 2002

Phys. Chem. Chem. Phys.

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High resolution (0.0011 cm À1 full width half maximum) diode laser spectra have been measured for mixtures of CF 2 Cl 2 in Ne, expanded in a supersonic planar jet. In addition interferometric Fourier transform infrared (FTIR) spectra have been recorded with a resolution of about 0.004 cm À1 (FWHM, Hamming apodization) for neat CF 2 Cl 2 , expanded through a circular 200 mm nozzle. We present the analysis of the n 3 + n 7 combination band of CF 2 35 Cl 2 [ñ n 0 ¼ 888.496 89(10) cm À1 ] and CF 2 35 Cl 37 Cl [ñ n 0 ¼ 883.203 89(12) cm À1]. Absolute band strengths have been measured for all bands falling in the atmospheric window (n 3 + n 7 , n 6 , n 1 and n 8 ) and thus being important for monitoring CF 2 Cl 2 in the lower troposphere and stratosphere. A Fermi resonance coupling constant W ¼ (15 AE 2) cm À1 is estimated for the resonance between n 3 + n 7 and n 6 in both isotopomers.

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“…Indeed, CFC-11 and CFC-12 show dense and sharp spectral structure at very high spectral resolution, even in the Q-branches (see, e.g. Orphal, 1991;McNaughton et al, 1994McNaughton et al, , 1995D'Amico et al, 2002). It is also important to note that comparisons of the absolute band intensities (see, e.g.…”

Section: Cfc Retrievalsmentioning

confidence: 99%

Global CFC-11 (CFCl₃) and CFC-12 (CF₂Cl₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

Kellmann¹,

Clarmann²,

Stiller³

et al. 2012

Preprint

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Vertical profiles of CFC-11 (CFCl₃) and CFC-12 (CF₂Cl₂) have been measured with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) with global coverage under daytime and nighttime conditions. The profile retrieval is based on constrained nonlinear least squares fitting of measured limb spectral radiance to modeled spectra. CFC-11 is measured in its ν₄-band at 850 cm⁻¹, and CFC-12 is analyzed in its ν₆-band at 922 cm⁻¹. To stabilize the retrievals, a Tikhonov-type smoothing constraint is applied. Main retrieval error sources are measurement noise and elevation pointing uncertainties. The estimated CFC-11 retrieval errors including noise and parameter errors but excluding spectroscopic data uncertainties are below 10 pptv in the middle stratosphere, depending on altitude, the MIPAS measurement mode and the actual atmospheric situation. For CFC-12 the total retrieval errors are below 28 pptv at an altitude resolution varying from 3 to 5 km. Time series of altitude/latitude bins were fitted by a simple parametric approach including constant and linear terms, a quasi-biennial oscillation (QBO) proxy and sine and cosine terms of several periods. In the time series from 2002 to 2011, quasi-biennial and annual oscillations are clearly visible. A decrease of stratospheric CFC mixing ratios in response to the Montreal Protocol is observed for most altitudes and latitudes. However, the trends differ from the trends measured in the troposphere, they are even positive at some latitudes and altitudes, and can in some cases only be explained by decadal changes in atmospheric age of air spectra or vertical mixing patterns

show abstract

High resolution FTIR spectroscopy of CFC's in a supersonic jet expansion

Cited by 11 publications

References 11 publications

Global CFC-11 (CCl₃F) and CFC-12 (CCl₂F₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

Global CFC-11 (CCl₃F) and CFC-12 (CCl₂F₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

Global CFC-11 (CFCl₃) and CFC-12 (CF₂Cl₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

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High resolution FTIR spectroscopy of CFC's in a supersonic jet expansion

Cited by 11 publications

References 11 publications

Global CFC-11 (CCl3F) and CFC-12 (CCl2F2) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

Global CFC-11 (CCl3F) and CFC-12 (CCl2F2) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

Global CFC-11 (CFCl3) and CFC-12 (CF2Cl2) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

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Global CFC-11 (CCl₃F) and CFC-12 (CCl₂F₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

Global CFC-11 (CCl₃F) and CFC-12 (CCl₂F₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

Global CFC-11 (CFCl₃) and CFC-12 (CF₂Cl₂) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends