Mechanisms limiting the growth of aeolian megaripples

Itzhak Katra, Hezi Yizhaq, Jasper F. Kok

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Megaripples are distinguished from regular ripples by their larger size and bimodal sediment distribution. The interplay between wind, grain size, and morphology controls their development, but the exact mechanisms that limit the size of megaripples have been unclear. Using wind tunnel experiments, we found two main mechanisms that limit the height of megaripples. The first mechanism is megaripple flattening due to strong enough winds that drive the coarse grains into saltation; the second mechanism is megaripple deflation by impacts of faster saltation grains. In this latter mechanism, the coarse grains are propelled by the impacts of fine saltating grains. The occurrence of both these mechanisms depends on the grain size distribution and increases with both megaripple height and wind speed. Thus, for a given wind environment and grain size distribution, there exists a limit on the size of megaripples, which is determined by these two mechanisms. Key Points Two mechanisms which limit the size of megaripples Both mechanisms depend on grain size, megaripple height and wind speed. For a given wind and grain size, there exists a limit on megaripples size.

Original languageEnglish
Pages (from-to)858-865
Number of pages8
JournalGeophysical Research Letters
Issue number3
StatePublished - 16 Feb 2014


  • fluid threshold
  • impact threshold
  • megaripples
  • saltation
  • wind tunnel

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences (all)


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