Passive remote monitoring of multi-gas mixtures by FTIR radiometry

摘要

The passive remote monitoring of multi-gas vapour mixtures by FTIR spectroscopy is investigated experimentally. The spectral radiance data were collected with the CATSI interferometer for a variety of multi-gas plumes at a distance of 60 m. Two basic sets of mixtures were studied. The first set corresponds to mixtures formed of three gases with no overlapping spectral bands (C_2H_2, C_2H_4 and R14). The second set corresponds to mixtures formed of three gases having overlapping spectral bands (C_2H_4, R114 and R134a). For each mixture the flow rates of individual constituents were adjusted to yield specific constituent CL ratios. These ratios are compared to the CL ratios retrieved from infrared radiance spectra. Results of this study indicate that for both sets of multi-gas mixtures the CL ratios retrieved by the passive remote monitoring technique agree well with those derived from the release flow rates. This good level of agreement was achieved by introducing a simple correction scheme to compensate for the limited accuracy of the fast radiance model implemented in the GASEM monitoring algorithm.