Remote SO2 flux by UV and TIR ground based cameras at Sabancaya volcano (Peru), cross comparison and validation with satellite data

During the 14^th IAVCEI Field Workshop held in Peru from 6 to 14 November 2022, SO₂ plume measurements were carried out remotely in the volcanic plume of Sabancaya volcano. Sabancaya is an active stratovolcano located in southern Peru (15.787°S, 71.857°W), Sabancaya’s first historical record of an eruption dates to 1750 and the most recent eruption began in November 2016. Volcanic activity consist of rhythm vulcanian explosions, which produce a gas-ash rich plumes which rose few km above the summit terrace. On 10 and 11 November 2022, side-by-side observation by UV and TIR ground-based cameras were remotely carried out with the object to observe the passive and active SO₂ burden from the volcanic plume of Sambacaya. Two UV cameras systems were employed observing the volcanic plume at 2- and 5-seconds time steps and calibrating SO₂ amounts by coupling SO₂ DOAS inverted column densities ad and SO₂-quartz cell amounts. The TIR camera (named VIRSO2) is a novel system developed for the detection of volcanic plumes, the estimation of the height and the determination of columnar content and the SO₂ flux. It allows acquisition of high frequency data both during the day and at night. It is equipped with 3 cameras, two broadband TIR (7-14 micron) and a VIS, capable of acquiring data simultaneously. For the quantitative estimation of SO₂, an 8.7 μm filter is installed in front of one of the TIR camera. Retrieved cameras products were cross-compared and validated in order to determinate limit an uncertainty of both methods and results were also compared with those obtained by S5p-TROPOMI instrument.

Preliminary results show a feasible strength between the three ground and space-based techniques. Within the uncertainties of each method, differences between inverted SO₂ column densities and emission rates arise from field of view geometrical sampling set-up and radiative transfer. Results gathered in this study prove the promising application of ground-based TIR in volcanic plume SO₂ observation.