Remote Sensing of Volcanic Emissions Using DOAS Systems, in the Framework of SAVER-Net Project

RAPONI M, ROVERE E, OTERO L, RISTORI P, MIZUNO A,; QUEL E

Kobe

Conferencia; The 13th International Conference on Atmospheric Sciences and Applications to Air Quality (ASAAQ13); 2015

The most recent volcanic events affecting the Southern South American Region were the eruption of the Chaiten (2008) and Puyehue-Cordón Caulle (P-CC) volcanoes (2011), the increase in the Hudson volcano activity (red alert in 2011), the eruption of the Copahue (2012), Villarrica and Calbuco volcanoes (2015). In particular, the huge volcanic activity of the P-CC volcano led to significant air travel disruption, suspending the activities of most airports in Patagonia for about 6 months. This was the largest aviation shutdown caused directly by airport and airspace closure due to the presence of volcanic ash, even in Buenos Aires airports (located about 1500 km from P-CC). One of the main scientific motivations in the context of remote sensing of volcanic emissions is to study the impact of degassing on the atmospheric chemistry at both tropospheric (quiescent degassing) and stratospheric (explosive eruptions) levels. In addition, the absolute magnitude and the relative speciation of the gaseous emissions can give us valuable information about the deeps volcanic processes occurring, thereby helping us to assess risk and to predict volcanic eruptions (Kern 2009). The Differential Optical Absorption Spectroscopy (DOAS) applied to volcanoes is a major breakthrough because this remote sensing technique can quantify and characterize trace gases from their characteristic cross sections in the ultraviolet, visible and near infrared spectrum far from the volcanic plume. Sulfur dioxide (SO2) can be considered a passive tracer during the first few hours after release into the atmosphere since its chemical conversion and deposition are quite slow in non-condensing volcanic plumes (Mc Gonigle et al. 2004). This gas has a differential cross section and spectral range that are easily detected using DOAS, and it also offers a valuable indicator of the volcanic activity and the risk associated with its gaseous and particulate emissions. Argentina, in collaboration with Chile and Japan (in the framework of the South American Environmental Risk Network international project, SAVER-Net), is intending to implement an atmospheric risk management system by means of the deployment of atmospheric monitoring stations and mesoscale models. The ground-based remote sensing instrumentation includes active (LIDAR) and - in the future - passive instruments like DOAS system. Through this project we expect to improve our knowledge about volcanic emissions using systematic monitoring of concentrations and flows of different gases (especially SO2). Our country lacks a DOAS monitoring network for volcanic gases and particles, therefore we expect to develop robust ground-based autonomous DOAS able to generate data within international standards. The design and development of a DOAS instrument to volcanic monitoring is presented.