Fourier transformation techniques are applied to high resolution laser spectra of water vapor to identify undesirable spectral features. Features such as interference fringes can be mathematically filtered from spectral information in the Fourier domain and the spectral data recovered by an inverse Fourier transformation. The combined use of second derivative detection and the Fourier transformation leads to significant enhancements of spectral information relative to both lower and higher frequency background interferences without a significant loss of resolution.