NASA Satellite Helps Measure Iceland Volcanic Plume
An instrument on NASA's Terra spacecraft is helping officials accurately estimate the heights of the massive ash plumes emitted by Iceland's Eyjafjallajokull volcano.
NASA's Terra satellite flew directly over Iceland on April 19, 2010, allowing its Multi-angle Imaging SpectroRadiometer (MISR) instrument to capture a series of images of the Eyjafjallajökull volcano and its erupting ash plume. The left panel of this image shows a view from MISR's nadir (vertical-viewing) camera, while the right panel contains a computer-analyzed map of plume heights, which have been corrected to compensate for the effects of wind. The heights are measured in meters, with red being highest and blue lowest. The smaller streamers of the plume are just several hundred meters above the surface, whereas the main plume extends to an altitude of about 4.5 kilometers (2.8 miles). This is smaller than the 7.3 kilometer (4.5 mile) altitude measured by MISR on April 14, 2010, though conditions remain highly dynamic.The accompanying images at right show the full nadir view at top, and a stereo anaglyph at bottom. The anaglyph was generated from MISR's nadir and 46-degree forward-viewing cameras. When the anaglyph is viewed through 3-D glasses, the plume height can be estimated.