High-resolution ground-based solar spectra recorded at the Amundsen-Scott South Pole station in Dec. 1980 and Nov. 1986 have been analyzed in the region of the CF2Cl2 (chlorofluorocarbon 12) ν8 band Q branches at 1161 cm-1. An increase in the CF2Cl2 total vertical column above the South Pole of 1.24 ± 0.15 over the 6-yr period, corresponding to an average rate of increase of 3.6 ± 2.1%, is derived. This rate of increase is lower than indicated by in situ measurements at the South Pole over the same time period, but there is agreement when the rather error bars of the spectral measurement results are considered. Spectroscopic parameters that can successfully model CF2C12 absorption at low temperatures are needed to improve retrieval accuracies and could be applied to a number of pre-1980 atmospheric spectral data sets in the literature to obtain an improved record of early CF2Cl2 concentration trends for comparison with estimates of historical release rates.
Curtis P. Rinsland, Aaron Goldman, Frank J. Murcray, Frank H. Murcray, David G. Murcray, and Joel S. Levine, "Infrared measurements of increased CF2Cl2 (CFC- 12) absorption above the South Pole," Appl. Opt. 27, 627-630 (1988)