Fourier-analytic technique for the separation of the signature of atmospheric ClO absorption from the solar background spectrum in the near ultraviolet

The high-resolution CIO absorption signature in the region of 308.1 nm has a very low absorption fraction, of the order of 6 x 10(-5), and linewidths comparable with those of the solar background spectrum. Because of the need for reliable absorption measurements of the abundance of this species, which is important in ozone photochemistry, a Fourier-analysis-based technique for the deconvolution of atmospheric solar absorption spectra in this region has been developed. The technique utilizes the regularity of the CIO spectrum and results in a significant reduction in the minimum signal-to-noise required for the retrieval of CIO abundances from absorption spectra.