Long-term evolution in the tropospheric concentration of chlorofluorocarbon 12 (CCl₂F₂) derived from high-spectral resolution infrared solar absorption spectra: retrieval and com

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• 作者：Rinsland ; Curtis P. ; Goldman ; Aaron ; Mahieu ; Emmanuel ; Zander ; Rodolphe ; Chiou ; Linda S. ; Hannigan ; James W. ; et. al.
• 关键词：Remote sensing ; Chlorofluorocarbons ; Troposphere ; Atmospheric chemistry ; Pollution ; Ozone
• 刊名：Journal of Quantitative Spectroscopy and Radiative Transfer
• 出版年：2005
• 期刊代码：70_00224073
• 类别：ch
• 出版时间：May 1, 2005
• 卷：92
• 期：2
• 页码：201-209
• 文件大小：403 K

摘要

The average tropospheric volume mixing ratios of chlorofluorocarbon 12 (CCl₂F₂) have been retrieved from high-spectral resolution ground-based infrared solar-absorption spectra recorded from March 1982 to October 2003 with the McMath Fourier transform spectrometer at the US National Solar Observatory facility on Kitt Peak in southern Arizona (31.9°N, 111.6°W, 2.09km altitude). The retrievals are based on fits to the unresolved Formula Not Shown band Q-branches near Formula Not Shown using the SFIT2 retrieval algorithm. The annual increase rate was equal to Formula Not Shown parts per trillion Formula Not Shown by volume at the beginning of the time series, March 1982, or Formula Not Shown, 1 sigma, declining progressively to Formula Not Shown parts per trillion, by volume at the end, October 2003, or Formula Not Shown, 1 sigma. Average tropospheric mixing ratios from the solar spectra have been compared with average surface flask and in situ sampling measurements from the Climate Monitoring and Diagnostics Laboratory (CMDL) station at Niwot Ridge, CO, (USA) (40.0°N, 105.5°W, 3013m altitude). The average ratio and standard deviation of the monthly means of the retrieved tropospheric mixing ratios relative to the CMDL surface mixing ratios is Formula Not Shown for the overlapping time period. Both datasets demonstrate the progressive impact of the Montreal protocol and its strengthening amendments on the trend of CCl₂F₂, though a tropospheric decrease has yet to be observed.