HR: 0800h
AN: V41A-07    [Abstracts]
TI: A Direct Comparison of MODIS and COSPEC Sulfur Dioxide Measurements of the May 21, 2003 Eruption Plume of Anatahan Volcano, Mariana Islands
AU: * Meier, V L
EM: vmeier@unm.edu
AF: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, United States
AU: * Meier, V L
EM: vmeier@unm.edu
AF: Center for Rapid Environmental Assessment & Terrain Evaluation (CREATE), Center for High Performance Computing University of New Mexico, Albuquerque, NM 87131, United States
AU: Scuderi, L
EM:
AF: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, United States
AU: Scuderi, L
EM:
AF: Center for Rapid Environmental Assessment & Terrain Evaluation (CREATE), Center for High Performance Computing University of New Mexico, Albuquerque, NM 87131, United States
AU: Fischer, T
EM:
AF: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, United States
AU: Hilton, D
EM:
AF: Geosciences Research Division Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, United States
AB: Quantifying the SO2 burden emitted from a volcano is critical to understanding a volcano's current state of activity. Ground-based instruments such as the correlation spectrometer (COSPEC) and the mini-DOAS are most routinely employed to measure volcanic SO2. Both instruments are human operated so they must be deployed on-site to obtain SO2 estimates. This makes it difficult and costly to regularly monitor active volcanoes world- wide. Satellite-based measurements, which can provide SO2 estimates in near real-time, have increasingly been used as a tool for volcanic monitoring. The Moderate Resolution Imaging Spectrometer (MODIS) located on board the Terra and Aqua satellites provides twice daily coverage of the Earth and has the capacity to detect volcanic SO2. The ability of MODIS to accurately detect and quantify SO2 in volcanic plumes using a SO2 retrieval program, MAP_SO2, was compared with COSPEC on the May 21, 2003 plume at Anatahan volcano (16.35oN, 145.67oE). MODIS was able to clearly detect SO2 in the plume and the MAP_SO2 derived SO2 flux was calculated (independently from the COSPEC data) to be more than twice the COSPEC derived flux (10,270 t/d and 3,000 - 4,500 t/d respectively). However, calculating a flux introduces additional errors. Therefore another means of comparing the two methods is utilized: a direct comparison of plume cross-sections from these two different methods. The MODIS image used with the MAP_SO2 program was acquired at 13:25 local time. The COSPEC traverse began at 13:35 local time and ended 14:40 local time. The time of the MODIS image acquisition and the start of the COSPEC traverse occurred within 10 minutes of each other. Although the MODIS image is a snap shot in time and the COSPEC traverse took about an hour to complete, the timing is so close that these two products are ideal for the comparison. The differences in these observations are used to better quantify SO2 emissions, to assess the current mismatch between ground-based and remotely sensed retrievals, and to aid in the development of an approach to continuously and accurately monitor volcanic activity from space in near real-time.
DE: 8419 Volcano monitoring (7280)
DE: 8430 Volcanic gases
DE: 8485 Remote sensing of volcanoes
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly