A new model of wind erosion in the presence of vegetation

Abstract

Vegetation is known to impact strongly the erosion of soil by the wind. Lateral cover is the primary parameter used to represent the amount of vegetation in aeolian research and, in particular, shear stress partitioning research. Although lateral cover provides a simple means for representing how much vegetation is in an area, it is not capable of characterizing how vegetation is distributed. A new, nonequilibrium model for the representation of nonerodible roughness elements is presented that uses the size distribution of erodible gaps between plants to characterize the ratio of the maximum shear stress to the average shear stress at the surface. The model shows very good agreement with measured shear stress ratios from the laboratory and field experiments. The model also satisfactorily explains relatively high horizontal aeolian sediment flux at high lateral cover. The relationship between this model and another shear stress partitioning model is explored, and the new model is found to be superior to the existing model because it (1) utilizes parameters with physical meaning that are measurable in the field or laboratory, (2) explains observations of horizontal flux at high cover, (3) overcomes difficulties inherent in the use of lateral cover to characterize vegetation on the surface, (4) is scale‐explicit, and (5) can be used at multiple scales from an individual unvegetated gap to an entire landscape.