Fourier transform spectrometer remote sensing of O2 A-band electric quadrupole transitions

Abstract: We observed electric quadrupole transitions in the O2 A-band, b 1Σg +←X 3Σg −(0,0), in high solar zenith angle atmospheric spectra recorded with the high-resolution solar-viewing Fourier transform spectrometer at Park Falls, WI. We identified 12 ΔN=±3 transitions for the first time, including the first detection of N O-branch transitions and extended the T S-branch observations of Brault [J Mol Spectrosc 1980;80:384–8] up to N″=23. Additionally, we observed six electric quadrupole transitions of the ΔN=−1 P O-branch. These observations demonstrate the excellent sensitivity and long-term stability of the new generation of solar-viewing Fourier transform spectrometers. [Copyright &y& Elsevier]