Two. Ripples

  1. Andrew Warren

Published Online: 27 MAR 2013

DOI: 10.1002/9781118295786.ch2

Dunes: Dynamics, Morphology, History

Dunes: Dynamics, Morphology, History

How to Cite

Warren, A. (2013) Ripples, in Dunes: Dynamics, Morphology, History, John Wiley & Sons, Oxford. doi: 10.1002/9781118295786.ch2

Publication History

  1. Published Online: 27 MAR 2013
  2. Published Print: 20 MAY 2013

ISBN Information

Print ISBN: 9781444339697

Online ISBN: 9781118295786



  • dunes;
  • flow response;
  • gravity wave;
  • mathematical model;
  • pattern formations;
  • ripples;
  • saltation length;
  • shadow zone


Windblown ripples cover all dry, bare, loose sandy surfaces. The most commonly distinguished subtype is the ‘mega-ripple’, on whose crests there is a (usually thin) layer of much coarser sand than on smaller ripples. This chapter describes some of the many blind alleys and the fewer open-ended alleys that have been proposed as explanations of ripples. The introduction of a ‘slip-face’ mechanism to a model of ripple formation improves its resemblance to real ripples. The models of ripple formation discussed are flow response, gravity wave, saltation length, shadow zone, and mathematical models. The most important conclusion from these models is that ripples, like dunes, are self-organising systems, whose pattern can be reproduced with a few rules. Pattern formations in ripples and dunes share some of the same mechanisms, for example the negative relationship between dune size and celerity and slip-face activity.