On October 18, 2002, a large dust plume extended across countries
bordering the eastern Mediterranean Sea. Information on the horizontal
and vertical extent of the dust are provided by these views from the
Multi-angle Imaging SpectroRadiometer (MISR). The left-hand panel
portrays the scene as viewed by the instrument’s vertical-viewing
(nadir) camera. Here only some of the dust over eastern Syria and
southeastern Turkey can be discerned. The dust is much more obvious in
the center panel, which is a view from MISR’s most steeply
forward-looking camera. In addition, this perspective makes shadows cast
by clouds onto the dust layer more apparent, providing a visual clue
that the dust is at a lower altitude than these clouds.
The right-hand panel is an elevation field derived from automated
MISR stereoscopic processing, in which the heights of clouds and certain
parts of the dust plume are retrieved. Because the stereoscopic approach
makes use of features within the images that exhibit spatial contrast,
heights for much of the dust plume (as well as the ocean surface) could
not be retrieved, and these areas are shown in dark gray. Clouds within
the image area are situated between about 2 and 5.5 kilometers above sea
level, and the dust is located below most of the cloud, at heights of
about 1.5 kilometers or less. When the stereo retrieval determines that
a location is at a near-surface altitude, digital terrain elevation data
are displayed instead. The highest clouds in this scene appear as the
orange and red areas, and mountainous regions are displayed in light
blue and green.
The Multi-angle Imaging SpectroRadiometer observes the daylit Earth
continuously from pole to pole, and every 9 days views the entire globe
between 82 degrees north and 82 degrees south latitude. The MISR Browse Image Viewer provides access to
low-resolution true-color versions of these images. These data
products were generated from a portion of the imagery acquired during
Terra orbit 15072. The panels cover an area of about 380 kilometers x
827 kilometers, and utilize data from blocks 58 to 65 within World
Reference System-2 path 174.
Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. Text by Clare Averill (Acro Service Corporation/Jet Propulsion Laboratory).