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

Irene Delgado-Fernandez, Thomas Smyth, DWT Jackson, Alex Smith, Robin Davidson-Arnott

Research output: Contribution to journalArticle

6 Citations (Scopus)
1 Downloads (Pure)

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.

Original languageEnglish
Pages (from-to)3084-3100
JournalJournal of Geophysical Research: Earth Surface
Volume123
Issue number11
Early online date5 Nov 2018
DOIs
Publication statusPublished - Nov 2018

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