A Survey of Volcanic Degassing in the Americas Since 2004

HR: 17:20h
AN: V44A-05 [Abstracts]
TI: A Survey of Volcanic Degassing in the Americas Since 2004
AU: * Carn, S A
EM: scarn@umbc.edu
AF: Joint Center for Earth Systems Technology (JCET), University of Maryland Baltimore County, 5523 Research Park Drive, Suite 320, Baltimore, MD 21228, United States
AU: Krotkov, N A
EM: krotkov@mhatter.gsfc.nasa.gov
AF: Goddard Earth Sciences and Technology (GEST) Center, University of Maryland Baltimore County, 5523 Research Park Drive, Suite 320, Baltimore, MD 21228, United States
AU: Krueger, A J
EM: akrueger@umbc.edu
AF: Joint Center for Earth Systems Technology (JCET), University of Maryland Baltimore County, 5523 Research Park Drive, Suite 320, Baltimore, MD 21228, United States
AU: Yang, K
EM: Kai.Yang.1@gsfc.nasa.gov
AF: Goddard Earth Sciences and Technology (GEST) Center, University of Maryland Baltimore County, 5523 Research Park Drive, Suite 320, Baltimore, MD 21228, United States
AB: The Ozone Monitoring Instrument (OMI) on NASA's Aura satellite is the first space-based instrument providing daily measurements of sulfur dioxide (SOŹ₂) in the lower troposphere and boundary layer. We use these daily observations, plus monthly and annual averages of OMI SO₂ data, to assess the magnitude and variability of SO₂ emissions from passive volcanic degassing in the Americas since September 2004. To properly assess the magnitude of non-eruptive degassing, any signal due to drifting eruption clouds must first be removed from the long-term averages. We derive a first-order evaluation of emission strengths from the maximum value of the average SO₂ vertical column density (VCD) measured close to sources. Emissions from well-known volcanic SO2 sources such as Kilauea, Popocatépetl, Masaya, Tungurahua, Láscar and Soufrière Hills are clearly identified. We also note elevated SO₂ VCDs close to the remote Lastarria volcano (Chile), with an ambiguous source that could be magmatic degassing and/or combustion of preexisting sulfur deposits. Several SO₂ anomalies are collocated with copper smelters in Peru and Chile, indicating significant anthropogenic SO₂ emissions in this region. Measurements of SO₂ emissions from Anatahan (CNMI) and Ubinas (Peru) demonstrate OMI's ability to identify and monitor episodic degassing at remote volcanoes. Detailed evaluation of relative source strengths requires accurate knowledge of the air mass factor (AMF) used in SO₂ retrievals and of local dispersion processes. The AMF depends on several parameters including the SO₂ vertical distribution, cloud fraction, aerosol loading, surface reflectivity, ozone column amount and satellite viewing geometry. Efforts to model and correct for the AMF dependence will be discussed. OMI measurements are an effective and economical tool for daily quantification of SO₂ emissions and surveys such as could be incorporated into regularly updated assessments of global volcanic and anthropogenic SO₂ production.
UR: http:so2.umbc.edu/omi
DE: 0370 Volcanic effects (8409)
DE: 8409 Atmospheric effects (0370)
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