We present a method to reduce the impact of source brightness fluctuations (SBFs) on spectra recorded by Fourier-transform spectrometry (FTS). Interferograms are recorded without AC coupling of the detector signal (DC mode). The SBF are determined by low-pass filtering of the DC interferograms, which are then reweighted by the low-pass, smoothed signal. Atmospheric solar absorption interferograms recorded in DC mode have been processed with and without this technique, and we demonstrate its efficacy in producing more consistent retrievals of atmospheric composition. We show that the reweighting algorithm improves retrievals from interferograms subject to both gray and nongray intensity fluctuations, making the algorithm applicable to atmospheric data contaminated by significant amounts of aerosol or cloud cover.
© 2007 Optical Society of America
Fourier Optics and Signal Processing
Original Manuscript: January 29, 2007
Revised Manuscript: March 19, 2007
Manuscript Accepted: March 22, 2007
Published: July 6, 2007
Gretchen Keppel-Aleks, Geoffrey C. Toon, Paul O. Wennberg, and Nicholas M. Deutscher, "Reducing the impact of source brightness fluctuations on spectra obtained by Fourier-transform spectrometry," Appl. Opt. 46, 4774-4779 (2007)