Combined direct-sun ultraviolet and infrared spectroscopies at Popocatépetl volcano (Mexico)

Volcanic plume composition is strongly influenced by both changes in magmatic systems and plume-atmosphere interactions. Understanding the degassing mechanisms controlling type of volcanic activity implies deciphering contributions gases reaching surface their posterior chemical transformations contact with atmosphere. Remote sensing techniques based on direct solar absorption spectroscopy provide valuable information about most emitted but also gas species formed converted within plumes. In this study, we explore procedures, performances benefits combining two techniques, high resolution Fourier Transform Infrared Spectroscopy (FTIR) Ultraviolet Differential Optical Absorption (UV-DOAS), to observe Popocatépetl’s temporal resolution. The SO 2 vertical columns obtained from three instruments (DOAS, FTIR Pandora) were found similar (median difference <12%) after intercalibration. We combined them determine different hydrogen halide halogen sulfur ratios (HF/SO , BrO/SO HCl/SO SiF 4 /SO detection limit HBr/SO ) HCl/BrO over a 2.5-years period (2017 mid-2019). BrO/HCl, range (0.63 ± 0.06 1.14 0.20) × 10 −4 (2.6 0.5 6.9 2.6) 0.08 0.01 0.21 respectively, while HF/SO fairly constant at (1.56 0.25) −3 0.049 0.001. especially focused full growth/destruction cycle voluminous lava dome that took place between February April 2019. A decrease ratio was observed extrusive activity. Furthermore, short-term variability measured for first time Popocatépetl volcano together revealing behaviors respect More generally, providing such temporally resolved near-real-time series primary secondary gaseous critical management emergencies, as well understanding processes impact atmospheric chemistry.