Size distribution and structure of Barchan dune fields

TL;DR

This paper introduces a spatially explicit model of barchan dune fields that incorporates dune interactions and collisions, successfully replicating observed size distributions but not the homogeneity along the wind direction.

Contribution

It presents a simplified, spatially explicit dune field model that accounts for dune interactions and compares results with real Moroccan dune fields.

Findings

Simulated dune size distributions match real data.

Model reproduces size distribution but not spatial homogeneity.

Dune interactions influence size stability.

Abstract

Barchans are isolated mobile dunes often organized in large dune fields. Dune fields seem to present a characteristic dune size and spacing, which suggests a cooperative behavior based on dune interaction. In Duran et al. (2009), we propose that the redistribution of sand by collisions between dunes is a key element for the stability and size selection of barchan dune fields. This approach was based on a mean-field model ignoring the spatial distribution of dune fields. Here, we present a simplified dune field model that includes the spatial evolution of individual dunes as well as their interaction through sand exchange and binary collisions. As a result, the dune field evolves towards a steady state that depends on the boundary conditions. Comparing our results with measurements of Moroccan dune fields, we find that the simulated fields have the same dune size distribution as in real fields but fail to reproduce their homogeneity along the wind direction.