HR: 14:25h
AN: V13G-04    [Abstracts]
TI: MAX-DOAS Measurement of Halogen Monoxides in a Volcanic Plume and Observation of Surface Ozone Depletion in the Vicinity of the Sakurajima Volcano in Japan
AU: * Lee, C
EM: cklee@gist.ac.kr
AF: Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju, 500-712 Korea, Republic of
AU: Kim, Y
EM: yjkim@gist.ac.kr
AF: Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju, 500-712 Korea, Republic of
AU: Tanimoto, H
EM: tanimoto@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506 Japan
AU: Mori, T
EM: mori@eqchem.s.u-tokyo.ac.jp
AF: University of Tokyo, 3-11-1, Asahi-cho, Fuchu, Tokyo, 183-8534 Japan
AU: Lee, H
EM: hanlim@gist.ac.kr
AF: Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju, 500-712 Korea, Republic of
AU: Yamamoto, K
EM: yamamoto@svo.dpri.kyoto-u.ac.jp
AF: Kyoto University, Sakurajimayokoyama, Kagoshima, 891-1419 Japan
AU: Hong, C
EM: hcs@gist.ac.kr
AF: Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju, 500-712 Korea, Republic of
AB: Enhanced BrO and ClO in the boundary layer associated with ozone destruction have been observed over salt lakes, as well as in the polar regions. Volcanic plume is a major natural source of atmospheric trace gases, influencing tropospheric and stratospheric trace gas budget. Though a variety of volcanic gases have been measured including BrO was found, there is still little information on other halogen oxides in volcanic plumes and their effects on atmospheric ozone. BrO and ClO in a volcanic plume from the Sakurajima volcano in Japan were measured using ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) from 22 May to 4 June 2004. Measured MAX-DOAS data were analyzed to identify and quantify BrO and ClO (as well as SO₂ and O₃) in the volcanic plume utilizing its specific structured absorption features in the ultraviolet region. Vertical scan through the multiple elevation angles was performed at different azimuth directions perpendicular to the plume dispersion direction to retrieve cross-sectional distribution of SO₂ in the plume based on the measured slant column density (SCD, the integrated concentration along the light path) values. SCDs observed during the measurement period range up to 1.4×10¹⁵ and 5.9×10¹⁶ molecules cm^-2 for BrO and ClO in the center of the plume. Calculated mixing ratios were ~0.7 and ~25.3 ppbv for BrO and ClO, respectively. Additionally halogen-catalyzed local surface ozone depletion was observed in the vicinity of the volcano. On the basis of the BrO to SO₂ and ClO to SO₂ ratios obtained by MAX-DOAS and the SO₂ and O₃ mixing ratio measured by the in-situ monitors installed 2.7 km from the active crater, the ozone destruction rate was observed up to 31 ppbv per hour. Halogen oxides in the Sakurajima volcanic plume exert effects on the surface ozone budget over the downwind area. As reactive halogen species emitted from a volcano have long lifetime (up to several days) as consequence of their recycling process, they can play an important role in the atmospheric chemistry.
DE: 0370 Volcanic effects (8409)
DE: 8409 Atmospheric effects (0370)
DE: 8430 Volcanic gases
DE: 8485 Remote sensing of volcanoes
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005