IMPROVING THE LARGE-SCALE MODELING OF THE SALTATION FLUX OF SOIL PARTICLES IN PRESENCE OF NONERODIBLE ELEMENTS

Stress partition between nonerodible obstacles and the underlying particle bed greatly influence erosion by wind in dry areas. Several studies have already been dedicated to this problem but their results cannot be used in large-scale modeling of the saltation flux because they always involve microscale parameters. Experiments are carried out in a wind tunnel to find a simplified expression of the stress partition coefficient, f, defined by Arya. Marbles of three different diameters are used to constitute nonerodible elements arrays of various densities. They are successively laid on three substrates of varying roughness. Results deduced from wind profile analysis then show that f can be expressed simply as a function of the roughness lengths of the overall terrain and of the underlying substrate, which can be determined relatively simply. The determination of f allows us to propose a more accurate calculation of the saltation flux for large-scale models of dust production.