Sandy, Salty Swirls

Fear Factory

In the Tanezrouft Basin of south-central Algeria, vegetation is sparse and sand is plentiful. Images like this one, taken by Japan’s Advanced Land Observing Satellite, provide researchers with an easy look at hard-to-reach areas to survey natural resources, monitor disasters, and track vegetation coverage.

Such imagery allows scientists to determine which areas warrant an expensive and difficult visit. The concentric shapes on the left are sandstone hills, rising above white salt flats. White rivers snake through the rocks—the salt remains after being leached from the soil by the rare rainstorms that pass through the Sahara Desert. Prevailing wind usually shapes sand dunes into curves or lines, but the yellow cluster of dunes, known as Erg Mehedjibat, grows upward instead of horizontally, suggesting that this region may lack consistent directional winds. And that thin line in the upper right, squiggling above the Erg? That’s the only road for miles.