An ILS for line parameters measurements in high resolved spectra recorded by FTS for atmospheric remote sensing purposes

Abstract

This communication presents a method that performs a nonlinear least-squares-fitting procedure that adjusts a modeled transmittance lines to match the observed spectrum taking into account a comprehensive modeling of the FTS instrumental apparatus function or what we call the Instrumental Line Shape (ILS). Consequently, one retrieves molecular spectral lines parameters (position, intensity, pressure broadening and pressure shifting) in a considered spectral window. For modeling the ILS, our method takes into account the influence of the throughput, of the phase error, and the non multiplying channeling (if any) 4, 5. An example will be given about line parameters measurements of Ozone6 (O3) pure rotational spectra. Emphasize will be made on the retrieval of line strengths.