draa
oxford
views updated May 18 2018draa A high (more than 300 m) sand ridge or chain of
dunes in the
Sahara, lying about 0.5–5 km from its nearest neighbour and moving at 2–5 cm per year. It is the largest land-form of the
erg or sand desert. A star-shaped dune, or ‘rhourd’, is developed at the site where two draa chains cross.
A Dictionary of Ecology MICHAEL ALLABY
draa
oxford
views updated May 08 2018draa High (more than 300 m) sand ridge or chain of
dunes in the
Sahara, lying about 0.5–5 km from its nearest neighbour and moving at 2–5 cm per year. It is the largest land-form of the
erg, or sand desert. A star-shaped dune, or ‘rhourd’, is developed at the site where two draa chains cross.
A Dictionary of Earth Sciences AILSA ALLABY and MICHAEL ALLABY
