WIDTH, HEIGHT AND SLOPE RELATIONSHIPS AND AERODYNAMIC MAINTENANCE OF BARCHANS

The allometric relationship between the height of barchan dunes and ho rn to horn widths is re-examined. The addition of new data from barcha n in the Namib Desert and elsewhere confirms the relationship that the height of a barchan is approximately one-tenth of the width of the du ne. Height and width of the dune are closely linked to the three-dimen sional morphology of the dune, in particular, the relatively constant mean angles of around 11 degrees at which the side slopes of the dune are maintained. We suggest that the 3-D barchan form is directly contr olled by aerodynamic processes. Constant feedback between three-dimens ional stoss face (windward) shape of the dune, slipface height and hor n to horn width, and shear stress produces an equilibrium dune form. ( C) 1998 Elsevier Science B.V.