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Figure 6.17
Plumes of mainly light-brown dust can be seen streaming off the high, arid plains of the central Andes Mountains in this view, which looks southwest toward the Pacific Ocean and Atacama Desert of northern Chile (across the top of view). Dust plumes are injected into the westerly winds above altitudes of 4,200 m-this oblique view shows the main plume intersecting the dark Cachi massif (C) at about 6,000 m. The visible length of the major dust plume in this view is approximately 240 km. The complexity of airstream circulations is apparent: dust plumes are transported by westerly winds (flow from top right to lower left) above altitudes of 4,200 m. The stratus cloud, with an upper surface at 3,290 m, is transported by gentle southerly winds (flow from left to right). The dust itself therefore rains down onto the stratus cloud (in the region of the arrows) before finally reaching the ground. This view shows that the dust pall increases albedos over the dark land surface, but decreases albedo of the cloud. (NASA photograph STS008-46-936, August 30, 1983, center point 25.5S 66.5W, Hasselblad camera, 100 mm lens; altitude 311 km.)