How would you distinguish between a parabolic dune and a barchan dune?

barchan dunes open away from the wind while parabolic dunes open facing the wind

That they are not called the same.duhhh

Barchan dunes are solitary crescent dunes formed on a flat, hard ground with limited supplies of sand and vegetation. Transverse dunes are a series of long ridges that are found in areas that have a...

Parabolic dunes have trailing arms because the arms are usually 'held back' by surface vegetation. The vegetation acts to limit sediment transport by wind action and to consolidate the surface sands.

dunes are formed by wind and the waves from the beach are caused by wind also.