Differential Optical Absorption Spectroscopy system for multi purpose applications

Topographic Target Light scattering - Differential Optical Absorption Spectroscopy (ToTAL-DOAS) is a novel atmospheric monitoring technique to obtain atmospheric trace gas concentrations from scattered sunlight measurements. The main issue to successfully apply this method is the need of a telescope to identify the targets clearly and efficiently couple light in a spectrometer. Also the need of measurements with different logistic requirements (e.g. from different platforms as from mobile, airborne, vessels, etc) it is of benefit to develop a new optical system for data acquisition. There are two key aspects to take into account: One of them is the importance to preserve a constant temperature on the spectrometer´s CCD. The second key aspect is to have a standalone unit which can be attached to different telescopes or to other optical devices in order to confront different experimental situations, and to be able to measure different optical parameters without the hassle of being concerned about the reliability of the spectrometer´s condition. Specifically, the aim of our work was to build a standalone hermetic housing for an Ocean Optics 2000+ spectrometer with temperature stabilization and portability. In this paper a description of the DOAS-System is presented as well as the results of preliminary test measurements by monitoring the trace gases SO2 and NO2 measured at the city of Montevideo.