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Coupling leeside grainfall to avalanche characteristics in aeolian dune dynamics

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posted on 06.01.2017 by Joanna M. Nield, Giles F.S. Wiggs, Matthew Baddock, Martin H.T. Hipondoka
Avalanche (grainflow) processes are fundamental drivers of dune morphodynamics and are typically initiated by grainfall accumulations. In sedimentary systems, however, the dynamism between grainfall and grainflow remains unspecified because simple measurements are hampered by the inherent instability of lee slopes. Here, for the first time, terrestrial laser scanning is used to quantify key aspects of the grainfall process on the lee (slip face) of a barchan sand dune. We determine grainfall zone extent and flux and show their variability under differing wind speeds. The increase in the downwind distance from the brink of peak grainfall under stronger winds provides a mechanism that explains the competence of large avalanches to descend the entire lee slope. These findings highlight important interactions between wind speed, grainfall, and subsequent grainflow that influence dune migration rates and are important for correct interpretation of dune stratigraphy.

Funding

This study was funded by National Geographic Society Science and Exploration Europe (GEFNE110-14), British Society for Geomorphology and NERC GEF )1025) grants.

History

School

  • Social Sciences

Department

  • Geography and Environment

Published in

Geology

Citation

NIELD, J.M. ...et al., 2017. Coupling leeside grainfall to avalanche characteristics in aeolian dune dynamics. Geology, 45(3), pp. 271-274.

Publisher

© The Authors. Published by the Geological Society of America

Version

NA (Not Applicable or Unknown)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by/4.0/

Acceptance date

02/12/2016

Publication date

2017

Notes

This is an Open Access Article. It is published by Geological Society of America under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

ISSN

0091-7613

eISSN

1943-2682

Language

en

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