A coupled vegetation/sediment transport model for dryland environments

Journal article

Dryland regions are characterised by patchy vegetation, erodible surfaces and erosive aeolian processes. Understanding how these constituent factors interact and shape landscape evolution is critical for managing potential environmental and anthropogenic impacts in drylands. However, modelling wind erosion on partially vegetated surfaces is a complex problem that has remained challenging for researchers. We present the new, coupled cellular automaton Vegetation and Sediment TrAnsport model (ViSTA), which is designed to address fundamental questions about the development of arid and semi-arid landscapes in a spatially explicit way. The technical aspects of the ViSTA model are described, including a new method for directly imposing oblique wind and transport directions onto a cell-based domain. Verification tests for the model are reported, including stable state solutions, the impact of drought and fire stress, wake flow dynamics, temporal scaling issues and the impact of feedbacks between sediment movement and vegetation growth on landscape morphology. The model is then used to simulate an equilibrium nebkha dunefield, and the resultant bedforms are shown to have very similar size and spacing characteristics to nebkhas observed in the Skeleton Coast, Namibia. The ViSTA model is a versatile geomorphological tool that could be used to predict threshold-related transitions in a range of dryland ecogeomorphic systems.

Authors: Mayaud, J; Bailey, R; Wiggs, G

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Journal of Geophysical Research: Earth Surface
• Volume: 122
• Issue: 4
• Pages: 875–900
• Publication date: 2017-03-31
• Acceptance date: 2017-03-28
• DOI: 10.1002/2016JF004096
• EISSN: 2169-9011
• ISSN: 2169-9011
• Keywords: dryland vegetation; complex systems; wind erosion; cellular automaton modelling