Yet another Redoubt volcanic eruption
GOES-11 visible, 3.9 µm IR, 10.7 µm IR, and IR "split window difference" images
The Mt. Redoubt volcano in Alaska experienced its 19th explosive event (in a series that began on 23 March) on 04 April 2009. GOES-11 visible, 3.9 µm shortwave IR (IR2), 10.7 µm IR window (IR4), and 10.7-11.0 µm “split window difference” images (above) showed that the southeastward advection of the volcanic plume became increasingly difficult to follow a few hours after the eruption.
However, the volcanic plume likely contained a good deal of water vapor, which made it easier to track on GOES-11 6.7 µm “water vapor channel” imagery (below) as it moved toward and eventually south of 50º N latitude after about 21:00 UTC.
GOES-11 6.7 µm water vapor images
Images of the MODIS 1.3 µm “cirrus detection channel” at 20:45 and 22:35 UTC (below) exhibited a signal of the leading edge of the volcanic plume as it approached and moved south of 50º N latitude (between 144º W and 142º W longitude). This MODIS near-IR channel is sensitive to particles that are efficient scatterers of light (such as smoke, haze, dust, ash), so these types of airborne particles to show up as slightly brighter features on grayscale-enhanced MODIS “cirrus detection channel” imagery.
Terra and Aqua MODIS near-IR "Cirrus detection channel" images
The extent of the long-range transport of the Redoubt SO2 plume was even more obvious on the AIRS Ozone Monitoring Instrument (OMI) SO2 24-hour composite image for 04 April (below).
AIRS OMI SO2 24-hour composite image