SPACEPHOTOS

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.