During fine weather,
        
        
          prepare for the storm rains.
        
        
          Madagascar
        
        
          
            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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