EOLIAN DUNES - COMPUTER-SIMULATIONS AND ATTRACTOR INTERPRETATION

A simple computer-simulation algorithm for the transport of sand by wi nd produces forms resembling barchan, crescentic ridge, linear, and st ar natural dune classes. Sand is moved as slabs composed of many grain s that are picked up at random, transported in a specified direction, and deposited (1) with a probability that depends on the local presenc e or absence of sand or (2) in shadow zones in the lee of dunes. The s imulated dune fields are interpreted as complex systems, with sand-dun e classes being dynamical attractors of these systems. The evolution o f dunes once formed becomes decoupled from the details of eolian sand transport.