Sustainable Development in Africa & Satellites - page 92

During fine weather,
prepare for the storm rains.
Land of colours
The pastel colours and soft, flowing shapes in this Envisat
radar image of the Tanezrouft Basin in the Algerian Sahara
contradict the harshness of the terrain that has led to it being
commonly referred to as the ‘Land of Terror’. Stone and pebbles
make up most of the Sahara surface in Northern Africa. Erosion
– first by water, now by wind – has created this landscape of hills,
basins, steep canyon walls, stone plateaus and multi-storey
sand dunes. This Envisat/ASAR combination of 3 radar passes
taken in 2009 reveals surface roughness – the rougher the
surface, the brighter it appears. Hence, darker areas represent
softer rock with a sandy or small-stoned surface. The colours
result from changes in the surface between acquisitions.
© ESA 2009
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