First portable scanning-DOAS system developed in Latin America for volcanic SO2 monitoring

RAPONI, MARCELO; VILAR, OSVALDO; ARBOLEAS, HUGO; GARCÍA, SEBASTIÁN; OTERO, LIDIA; PEREYRA, ANDREA; MARTORELLA, EVANGELINA; GÓMEZ, MARTÍN

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2021 vol. 108

0895-9811

Due to the extreme conditions in volcanic environments, in-situ sampling of gases is considered a very dangerous task. For this reason, the implementation of new remote sensing techniques and instruments has become a fundamental tool for monitoring volcanic activity. This work presents the design and development of a system - known as scanning-DOAS - that allows to remotely monitor (from a safe distance) the sulfur dioxide (SO2) concentration of a volcanic plume. The instrument measures the solar radiation that reaches its CCD (Charge-Coupled Device) detector after passing through the plume. The spectral signals are recorded by a spectrometer and then processed using an inversion algorithm based on the DOAS technique (Differential Optical Absorption Spectroscopy). As a result of the analysis, the SO2 concentration in the cross section of the plume is obtained. Knowing the plume´s height, speed and direction of propagation it is possible to calculate the gas flux. This work describes the constructive characteristics of a new prototype, which incorporates improvements based on the results obtained from a first prototype that was tested during a monitoring campaign carried out at Planchón-Peteroa Volcanic Complex (Malargüe, Mendoza province, Argentina) in the year 2017.