Dune formation under bimodal winds Academic Article uri icon


  • The study of dune morphology represents a valuable tool in the investigation of planetary wind systems--the primary factor controlling the dune shape is the wind directionality. However, our understanding of dune formation is still limited to the simplest situation of unidirectional winds: There is no model that solves the equations of sand transport under the most common situation of seasonally varying wind directions. Here we present the calculation of sand transport under bimodal winds using a dune model that is extended to account for more than one wind direction. Our calculations show that dunes align longitudinally to the resultant wind trend if the angle(w) between the wind directions is larger than 90 degrees. Under high sand availability, linear seif dunes are obtained, the intriguing meandering shape of which is found to be controlled by the dune height and by the time the wind lasts at each one of the two wind directions. Unusual dune shapes including the "wedge dunes" observed on Mars appear within a wide spectrum of bimodal dune morphologies under low sand availability.

published proceedings

  • Proceedings of the National Academy of Sciences of the United States of America

author list (cited authors)

  • Parteli, E., Duran, O., Tsoar, H., Schwammle, V., & Herrmann, H. J.

citation count

  • 101

complete list of authors

  • Parteli, EJR||Duran, O||Tsoar, H||Schwammle, V||Herrmann, HJ

publication date

  • December 2009