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Global Satellite Observations of Volcanic Global Satellite Observations of Volcanic Plumes for Aviation Hazard MitigationPlumes for Aviation Hazard Mitigation
Kai Yang (GSFC/NASA and GEST/UMBC)Kai Yang (GSFC/NASA and GEST/UMBC)Nick Krotkov (GSFC/NASA)Nick Krotkov (GSFC/NASA)
Simon Carn (MTU), Arlin Krueger (UMBC), Simon Carn (MTU), Arlin Krueger (UMBC), Gilberto Vicente (NOAA), Eric Hughes (NOAA)Gilberto Vicente (NOAA), Eric Hughes (NOAA)
Motivations
• For aviation decision support, timely information about volcanic plumes is needed, especially their spatial locations, mass loadings, and vertical extents.
• These measurements provide critical inputs to numerical models for forecasting volcanic cloud hazards.
Detection of Volcanic Ash
• IR ash detection:– Absorption of warm
underlying IR emission by ash using spectral features to distinguish them from normal water clouds
– Plume must be thin to allow sufficient IR transmission
– Plume must be colder than underlying surface
• Fresh ash clouds are:– Dense, must wait until
sheared to thin layer
– Full of water/ice
• UV ash (AI) detection:– Absorption and scattering of
UV radiation by ash provide spectral contrast that differs from normal clouds and Rayleigh scattering
– Sunlight necessary
• Fresh ash clouds are:– Detected upon eruption
– Independent of water/ice content or surface conditions
– Detectable down to the lower troposphere
– Not detectable at night
Kasatochi Ash, August 9th 2008
Volcanic Ash Detections: UV and IR
AIRS ΔBT (°K)
OMI Aerosol Index
SO2 as proxy for more reliable volcanic plume detection and
tracking• Volcanic plume behavior
– Explosive magmatic eruptions contain both ash and SO2
– SO2 is usually easier to detect than ash (proxy)– Dense ash falls out in 2 - 4 days– SO2 lasts for weeks
• Value of UV data– Potential for early detection of ash (AI) and SO2
– Provide direct (SO2) plume height– Measure degassing to monitor volcanic unrest
• Many eruptions observed by Aura/OMI since 2005 for evaluating this approach
SO2 and Ash detection in very fresh(< 2 hrs) eruption clouds from OMI
Montserrat; 2/11/2010Okmok; 7/12/2008 Kasatochi; 8/8/2008
SO2
Ash
Global Span of Volcanic SO2 Plumes:
Kasatochi August 7, 2008
Direct SO2 Plume Height Estimation
GOME-2 OMI
GOME-2 SO2:Total Mass:1.5 Mt
OMI SO2:Total Mass:1.6 Mt
SO2
Height
SO2 Height Histogram
Comparison with CALIPSO Plume Height
Eyjafjallajökull Ash: Aerosol Index
GOME-2 OMI
Eyjafjallajökull SO2 Plume
SO2 column SO2 height Height Histogram
NRT Volcano Monitoring The NOAA/NESDIS OMI SO2 product delivery and visualization user interface
http://satepsanone.nesdis.noaa.gov/pub/OMI/OMISO2/
Global compositesGlobal composites
Volcano sectorsVolcano sectors
Satellite orbitSatellite orbit
Digital imagesDigital images
NOAA OMI SONOAA OMI SO22 experimental automated alarm system: experimental automated alarm system:Anomalous SOAnomalous SO22 concentrations automatically detected in concentrations automatically detected in the most recent OMI data: Merapi eruption November 5-6the most recent OMI data: Merapi eruption November 5-6
Merapi (Java) eruption November 5-6
OMI SO2 is used as proxy for volcanic clouds, can be seen longer than ash
OMI UV Aerosol Index (AI) shows directly sunlight reflection by ash
Planned Research: Synergy of Joint UV and IR Retrievals
• Both UV and IR measurements are sensitive to ash particle size and composition, and its vertical location.
• Combining hyper-spectral UV (OMI, GOME2) and IR (AIRS, IASI) measurements provides greater constraints to a retrieval algorithm, and likely leads to more accurate estimates of volcanic ash height and loading.
• Near-Real-Time data service (Aerosol Index/SO2
amount and height) from UV sensors: NPP/OMPS and ESA/TROPOMI
• Improvement in quantification of volcanic ash loading and height, likely achieved by combining retrievals of hyper-spectral UV and IR measurements
• Improvement in volcanic ash monitoring and forecasting by merging satellite measurements and numerical models
Future Efforts