The 1-μm CO2 bands and the O2 (0-1) X3Σg- a1Δg and (1-0) X3Σg-- b1Σg+ bands in the Earth atmosphere

The CO2 triad of bands in the 9300-9700 cm(-1) region have been observed in near infrared 0.05 cm(-1) resolution ground-based solar absorption spectra. This interval is a portion of spectra taken in the 900012,000 cm(-1) region, at large solar zenith angles. Considering the available line positions and pressure line shifts for CO2, H2O and O-2 in this region as of 2000, it was concluded that these observations show significant inconsistencies among the line positions of the species as listed in the atmospheric spectroscopy databases. The spectra allow a better definition of the O-2 (0-1) X(3)Sigma(g)(-) - a(1)Delta(g) band, with the discrete (0-1) transitions observable in the 9300-9450 cm(-1), superimposed on a collision-induced continuum covering the 9200-9700 cm(-1) region. This continuum, as well as the (0-0) continuum in the 7900 cm(-1) region, have been previously studied only from atmospheric spectra with much lower spectral resolution. The discrete O-2 (1-0) transitions of the X(3)Sigma(g)(-) - b(1)Sigma(g)(+) atmospheric B-band are observed in the 11,500-11,600 cm(-1) region, but no evidence is found for an underlying continuum. A recent laboratory study of the 2v(1) + 3v(3) (CO2)-C-12 triad significantly improves the consistency between the O-2, H2O and CO2 lines in the atmospheric spectra. (C) 2003 Elsevier Ltd. All rights reserved.