Atmospheric Measurement Techniques (Jan 2014)

Spectrometric monitoring of atmospheric carbon tetrafluoride (CF<sub>4</sub>) above the Jungfraujoch station since 1989: evidence of continued increase but at a slowing rate

  • E. Mahieu,
  • R. Zander,
  • G. C. Toon,
  • M. K. Vollmer,
  • S. Reimann,
  • J. Mühle,
  • W. Bader,
  • B. Bovy,
  • B. Lejeune,
  • C. Servais,
  • P. Demoulin,
  • G. Roland,
  • P. F. Bernath,
  • C. D. Boone,
  • K. A. Walker,
  • P. Duchatelet

DOI
https://doi.org/10.5194/amt-7-333-2014
Journal volume & issue
Vol. 7, no. 1
pp. 333 – 344

Abstract

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The long-term evolution of the vertical column abundance of carbon tetrafluoride (CF4) above the high-altitude Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.) has been derived from the spectrometric analysis of Fourier transform infrared solar spectra recorded at that site between 1989 and 2012. The investigation is based on a multi-microwindow approach, two encompassing pairs of absorption lines belonging to the R-branch of the strong ν3 band of CF4 centered at 1283 cm−1, and two additional ones to optimally account for weak but overlapping HNO3 interferences. The analysis reveals a steady accumulation of the very long-lived CF4 above the Jungfraujoch at mean rates of (1.38 ± 0.11) × 1013 molec cm−2 yr−1 from 1989 to 1997, and (0.98 ± 0.02) × 1013 molec cm−2 yr−1 from 1998 to 2012, which correspond to linear growth rates of 1.71 ± 0.14 and 1.04 ± 0.02% yr−1 respectively referenced to 1989 and 1998. Related global CF4 anthropogenic emissions required to sustain these mean increases correspond to 15.8 ± 1.3 and 11.1 ± 0.2 Gg yr−1 over the above specified time intervals. Findings reported here are compared and discussed with respect to relevant northern mid-latitude results obtained remotely from space and balloons as well as in situ at the ground, including new gas chromatography mass spectrometry measurements performed at the Jungfraujoch since 2010.