MISR images of the Ntwetwe and Sua Pans in northeastern Botswana,
acquired on August 18, 2000 (Terra orbit 3553). The left
image is a color view from the vertical-viewing (nadir) camera. On the
right is a composite of red band imagery in which the 45-degree aft camera
data are displayed in blue, 45-degree forward as green, and vertical as
red. This combination causes wet areas to appear blue because of the
glint-like reflection from water and damp surfaces. Clouds are visible in
the upper left corner and right center of each image. The clouds look
peculiar in the multi-angle view because geometric parallax resulting from
their elevation above the surface causes a misregistration of the
individual images making up the composite. This stereoscopic effect
provides a way of distinguishing clouds from bright surfaces.
The images are approximately 250 kilometers across. Ntwetwe and
Sua pans are closed interior basins that catch rainwater and surface
runoff during the wet season. Seasonal lakes form that may reach
several meters in depth. During the dry season the collected waters
rapidly evaporate leaving behind dissolved salts that coat the surface
and turn it bright ("sua" means salt). The mining town of Sowa is located
where the Sua Spit (a finger of grassland extending into the pan)
attaches to the shore. Sowa represents headquarters for a JPL contingent
carrying out MISR field experiments using the evaporite surface and the
grasslands as targets and for Botswana scientists studying migration of
groundwaters beneath the pans and surrounding areas. These efforts
support the Southern Africa Regional Science Initiative (SAFARI-2000),
which is now underway.
Image Credit: NASA/GSFC/JPL, MISR Science Team
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