article_snippet.sent: Linear dunes, like these captured by the Nasa's Landsat 7 satellite, are straight ridges of sand that have been known to measure as long as 99 miles (160km).
article_snippet.sent: Linear dunes are straight ridges of sand that have been known to measure as long as 99 miles (160km).
article_snippet.sent: Ridges are categorised as linear when Ridges are significantly longer than Ridges are wide, and Ridges occur on isolated ridges of dunes as well as, more commonly, as sets of parallel ridges separated by miles of sand and gravel.
article_snippet.sent: Linear dunes are straight ridges of sand that have been known to measure as long as 99 miles (160km).
article_snippet.sent: Ridges are categorised as linear when Ridges are significantly longer than Ridges are wide, and Ridges occur on isolated ridges of dunes as well as, more commonly, as sets of parallel ridges separated by miles of sand, gravel.
article_snippet.sent: Linear dunes are aligned in the direction of the prevailing wind and are spaced 1.2 miles (2km apart)', explained Steven Hanna. '
article_snippet.sent: Ridges are categorised as linear when Ridges are significantly longer than Ridges are wide, and Ridges occur on isolated ridges of dunes as well as sets of parallel ridges separated by miles of sand and gravel.
article_snippet.sent: they become linear (pictured left centre and in Morocco right)