Capability and limitations in measuring atmospheric nitrogen dioxide column amounts by means of the MKIV Brewer spectrophotometers

A new algorithm to determine the nitrogen dioxide column density in the atmosphere using the MKIV Brewer spectrophotometers is proposed. The updated technique minimizes the measurement noise and the contribution of several natural and instrumental factors that could interfere with the measurement. For that, recent spectroscopic data are employed in the retrieval and a new set of weighting factors was recalculated taking into account the instrumental characteristics of a real MKIV Brewer. The algorithm was successfully tested on a set of synthetic spectra simulated with a radiative transfer code.