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