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Investigating parabolic and nebkha dune formation using a cellular automaton modelling approach

Nield, J.M. and Baas, A.C.W. (2008) Investigating parabolic and nebkha dune formation using a cellular automaton modelling approach Earth Surface Processes and Landforms, 33, (5), pp. 724-740. (doi:10.1002/esp.1571).

Record type: Article

Abstract

Vegetation plays an important role in shaping the morphology of aeolian dune landscapes in coastal and semi-arid environments, where ecogeomorphic interactions are complex and not well quantified. We present a Discrete ECogeomorphic Aeolian Landscape model (DECAL) capable of simulating realistic looking vegetated dune forms, permitting exploration of relationships between ecological and morphological processes at different temporal and spatial scales. The cellular automaton algorithm applies three simple rules that lead to self-organization of complex dune environments, including nebkhas with distinctive deposition tails that form in association with mesquite-type shrubs, and hairpin (long-walled) parabolic dunes with trailing ridges that evolve from blowouts in association with vegetation succession. Changing the conditions of simulations produces differing landscapes that conform qualitatively to observations of real-world dunes. The model mimics the response of the morphology to changes in sediment supply, vegetation distribution, density and growth characteristics, as well as initial disturbances. The introduction of vegetation into the model links spatial and temporal scales, previously dimensionless in bare-sand cellular automata. Grid resolutions coarser than the representative size of the modelled vegetation elements yield similar morphologies, but when cell size is reduced to much smaller dimensions, the resultant landscape evolution is dramatically different. The model furthermore demonstrates that the relative response characteristics of the multiple vegetation types and their mutual feedback with geomorphological processes impart a significant influence on landscape equilibria, suggesting that vegetation induces a characteristic length scale in aeolian environments. This simple vegetated dune model illustrates the power and versatility of a cellular automaton approach for exploring the effects of interactions between ecology and geomorphology in complex earth surface systems.

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More information

Submitted date: 21 March 2007
Published date: 2008
Keywords: vegetation, parabolic dunes, nebkhas, cellular automata, self-organization

Identifiers

Local EPrints ID: 49230
URI: http://eprints.soton.ac.uk/id/eprint/49230
ISSN: 0197-9337
PURE UUID: 3f263ac0-529f-42d4-a3c8-ec7e9edcbe56
ORCID for J.M. Nield: ORCID iD orcid.org/0000-0002-2657-0525

Catalogue record

Date deposited: 25 Oct 2007
Last modified: 17 Jul 2017 14:56

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Contributors

Author: J.M. Nield ORCID iD
Author: A.C.W. Baas

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