Aeolian sand dunes originate from wind flow and sand bed interactions. According to wind properties and sand availability, they can adopt different shapes, ranging from huge motion-less star dunes to small and mobile barchan dunes. The latter are crescentic and emerge under a unidirectional wind, with a low sand supply. Here, a 3d model for barchan based on existing 2d model is proposed. After ...

Golan Bel and Yosef Ashkenazy Department of Environmental Physics, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel (Dated: May 11, 2014) Abstract Psammophilous plants are special plants that flourish in sand moving environments. There are two main mechanisms by which the wind affects these plants: (i) sand drift exposes roots and cov...

The Olympic Dam archaeological salvage program covers an area of 600 km2 and contains more than 16,500 archaeological sites, most of which are open scatters of stone artefacts on linear sand dunes. Optically stimulated luminescence (OSL) dating offers an opportunity to date recent phases of dune movement and stability, and to provide a chronology for archaeological material on and in the sand b...

Sand-moving winds blowing from a constant direction in an area of high sand availability form transverse dunes, which have a fixed profile in the direction orthogonal to the wind. Here we show, by means of a linear stability analysis, that transverse dunes are intrinsically unstable. Any along-axis perturbation on a transverse dune amplify in the course of dune migration due to the combined eff...

This study represents the first characterization of sand microbiota in migrating barchan sand dunes. Bacterial communities were studied through direct counts and cultivation, as well as 16S rRNA gene and metagenomic sequence analysis to gain an understanding of microbial abundance, diversity, and potential metabolic capabilities. Direct on-grain cell counts gave an average of 5.3 ± 0.4 x 105 ce...

Sand dunes form an important and unique system that can be mobile or fixed by vegetation. The common mobility indices of sand dunes, which are related to the wind and the amount of precipitation and potential evaporation, do not work in many dune fields around the world. The reasons for that lie in the singular physical characteristics of the sandy soil. Sand has high hydraulic conductivity cau...

Clematis flammula var. maritima is a woody lianoid plant that grows on coastal sand dunes in the Mediterranean region. Older perennial stems are present as extensive underground axes. These generate surface growth of shorter-lived stems producing monospecific trellises above the surface of the sand. Despite its sand dune habitat and shortage of host support plants, this variety of Clematis show...

We investigate flow separation in the air flow over transverse sand dunes. CFD simulations of the air flow over differently shaped dunes are performed. The length of the recirculation region after the brink of the dune is found to depend strongly on the shape of the dune. We find that the nondimensionalised separation length depends linearly on the slope of the dune at the brink within a large ...

A mathematical formulation is developed to model the dynamics of sand dunes. The physical processes display strong non-linearity that has been taken into account in the model. When assessing the success of such a model in capturing physical features we monitor morphology, dune growth, dune migration and spatial patterns within a dune field. Following recent advances, the proposed model is based...

Preservation and effective management of highly dynamic coastal features located in areas under development pressures requires in-depth understanding of their evolution. Modern geospatial technologies such as lidar, real time kinematic GPS, and three-dimensional GIS provide tools for efficient acquisition of high resolution data, geospatial analysis, feature extraction, and quantification of ch...