Aeolian dune field self-organization - implications for the formation of simple versus complex dune-field patterns

The interpretation of aeolian dune-field patterns as self-organizing complex systems is a new paradigm in which pattern evolution may be addressed. Computer simulations, supported by field and experimental data, indicate that a given wind regime produces a simple dune-field pattern. Dune type and crest orientation are determined by wind regime and pattern ordering occurs through dune-dune interactions over time. Because dunes reorient only at their crest terminations with a change in wind regime, the rate of formation of a new pattern of small dunes is typically faster than the rate of reorientation of the existing pattern, resulting in the superposition of simple patterns to give rise to complex patterns. Complex patterns are distinct from spatial changes in a simple pattern, and from the type of superposition that characterizes compound/complex dunes. Complex patterns necessarily indicate a rate of pattern formation that is rapid compared to the rate of sediment accumulation on the depositional surface. (c) 2005 Elsevier B.V. All rights reserved.