NUMERICAL-ANALYSIS AND ESTIMATION OF THE STATISTICAL ERROR OF DIFFERENTIAL OPTICAL-ABSORPTION SPECTROSCOPY MEASUREMENTS WITH LEAST-SQUARES METHODS

Differential optical absorption spectroscopy (DOAS) has become a widel y used method to measure trace gases in the atmosphere. Their concentr ation is retrieved by a numerical analysis of the atmospheric absorpti on spectra, which often are a combination of overlapping absorption st ructures of several trace gases. A new analysis procedure was develope d, modeling atmospheric spectra with the absorption structures of the individual trace gases, to determine their concentrations. The procedu re also corrects differences in the wavelength-pixel mapping of these spectra. A new method to estimate the error of the concentrations cons iders the uncertainty of this correction and the influence of random r esidual structures in the absorption spectra. (C) 1996 Optical Society of America