Remote monitoring of volcanic gases using passive Fourier transform spectroscopy

• Main Authors: Love, S.P., Goff, F., Counce, D., Schmidt, S.C., Siebe, C., Delgado, H.
• Other Authors: United States. Department of Energy. Office of the Assistant Secretary, Management and Administration.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Los Alamos National Laboratory 1999
• Subjects: Fourier Transform Spectrometers; Mexico; Remote Sensing; Italy; Hawaii; Air Pollution; 58 Geosciences; Climatic Change; 54 Environmental Sciences; Volcanic Gases; Volcanoes; New Zealand; Performance; White Island
• Online Access: http://digital.library.unt.edu/ark:/67531/metadc676623/

Volcanic gases provide important insights on the internal workings of volcanoes and changes in their composition and total flux can warn of impending changes in a volcano`s eruptive state. In addition, volcanoes are important contributors to the earth`s atmosphere, and understanding this volcanic contribution is crucial for unraveling the effect of anthropogenic gases on the global climate. Studies of volcanic gases have long relied upon direct in situ sampling, which requires volcanologists to work on-site within a volcanic crater. In recent years, spectroscopic techniques have increasingly been employed to obtain information on volcanic gases from greater distances and thus at reduced risk. These techniques have included UV correlation spectroscopy (Cospec) for SO{sub 2} monitoring, the most widely-used technique, and infrared spectroscopy in a variety of configurations, both open- and closed-path. Francis et al. have demonstrated good results using the sun as the IR source. This solar occultation technique is quite useful, but puts rather strong restrictions on the location of instrument and is thus best suited to more accessible volcanoes. In order to maximize the flexibility and range of FTIR measurements at volcanoes, work over the last few years has emphasized techniques which utilize the strong radiance contrast between the volcanic gas plume and the sky. The authors have successfully employed these techniques at several volcanoes, including the White Island and Ruapehu volcanoes in New Zealand, the Kilauea volcano on Hawaii, and Mt. Etna in Italy. But Popocatepetl (5452 m), the recently re-awakened volcano 70 km southeast of downtown Mexico City, has provided perhaps the best examples to date of the usefulness of these techniques.