Mount Etna Eruption - MODIS Images

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Click on image for larger version

The eruption of Mt. Etna was overflown by the MODIS instrument on the NASA Aqua satellite on 28 October 2002. CIMSS scientists were interested in the composition of the plume which can be seen as the brown cloud spewing out of the volcano in the true color MODIS image. In previous cases involving volcano eruptions, it was conjectured that the plume contained a high volume of ash (negative values of BTD11-12) and SO2, which causes a large negative brightness temperature differences between the 8.5 and 11-micron bands (BTD8-11). With Etna, the BTDs between different spectral regions suggests that presence of ash since the BT11-12 values are negative. The surprising feature found in this plume is the presence of large positive BT8-11 values, suggesting the presence of small ice particles. If true, the question is whether a substance is present in the plume that promotes rapid ice formation. Further investigations using other instruments onboard Aqua are expected help to identify the exact plume composition.

Images provided by Kathy Strabala and NASA.
Text provided by Bryan Baum.

See also:
MODIS Image Gallery
MODIS Direct Broadcast at SSEC page
SSEC Images and Data
SSEC Volcano Watch

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