A singular value decomposition approach for the retrieval of N2O concentrations and fluxes by quantum cascade laser absorption spectroscopy

In this paper, we discuss the interest of the singular value decomposition (SVD) data processing method applied to the in situ monitoring of gases (N₂O) b mid-infrared quantum cascade laser absorption spectroscopy. An approach by simulation is used to determine the most appropriate parameters of the SVD treatment for this specific laser sensing application. The simulation is further used to estimate the effectiveness of the SVD in terms of improvement of the concentration data precision. Finally, the proposed SVD method is applied to experimental N₂O measurements achieved in the laboratory with calibrated gas samples and with N₂O flux measurements yielded during a field campaign in farm parcels.