Event-scale dynamics of a parabolic dune and its relevance for meso-scale evolution

Delgado-Fernandez, I and Smyth, T.A.G. and Jackson, D.W.T. and Smith, A.B. and Davidson-Arnott, R.G.D. (2018) Event-scale dynamics of a parabolic dune and its relevance for meso-scale evolution. Journal of Geophysical Research: Earth Surface. ISSN 2169-9011

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Abstract

Parabolic dunes are wide-spread aeolian landforms found in a variety of environments. Despite modelling advances and good understanding of how they evolve, there is limited empirical data on their dynamics at short time-scales of hours, and on how these dynamics relate to their medium-term evolution. This study presents the most comprehensive dataset to date on aeolian processes (airflow and sediment transport) inside a parabolic dune at an event-scale. This is coupled with information on elevation changes inside the landform to understand its morphological response to a single wind event. Results are contextualized against the medium-term (years) allowing us to investigate one of the most persistent conundrums in geomorphology, that of the significance of short-term findings for landform evolution. Our field data suggested three key findings: 1) sediment transport rates inside parabolic dunes correlate well with wind speeds rather than turbulence; 2) up to several tonnes of sand can move through these landforms in a few hours; 3) short-term elevation changes inside parabolic dunes can be complex and different from long-term net spatial patterns, including simultaneous erosion and accumulation along the same wall. Modeled airflow patterns along the basin were similar to those measured in situ for a range of common wind directions, demonstrating the potential for strong transport during multiple events. Meso-scale analyses suggested that the measured event was representative of the type of events potentially driving significant geomorphic changes over years, with supply-limiting conditions playing an important role in resultant flux amounts.

Item Type: Article
Additional Information and Comments: ©2018. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Faculty / Department: Faculty of Science > Geography and Environmental Science
Depositing User: Thomas Smyth
Date Deposited: 19 Nov 2018 09:33
Last Modified: 13 Dec 2019 14:40
URI: https://hira.hope.ac.uk/id/eprint/2659

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