Full particle size distribution characteristics of land surface sediment and their effect on wind erosion resistance in arid and semiarid regions of Northwest China

Particle size distribution (PSD) is one of the fundamental physical properties of clastic sediment. Although many mathematical models have been proposed to describe the PSD of sediment, the physical meaning behind model parameter characterization remains poorly understood, which means it is seldom used in studies of the environment, geomorphologic evolution, and related surface wind-sand processes in arid areas. In this study, based on the Li model of the PSD of sediment, the parameters of sediment obtained from different landscapes in Northwest China were investigated and their relationship with the resistance of sediment to wind erosion was analyzed. Results showed that the full PSD parameters (mu and Dc) of the Li model not only revealed the full PSD of the surface sediment of the various landscapes, but also reflected the differences in sediment structure. The full PSD parameters of fine silty, sandy, and sandy gravel surface sediment were -0.2 < mu < 0 and Dc < 0.08,-0.2 < mu < 0 and 0.08 <= Dc <= 0.2, and mu < 0 and Dc > 0.2, respectively. Parameter Dc not only represents the mean particle size of sediment, but it also indicates the degree of sorting, that is, it has a positive linear correlation with the component content of coarser particles in the sediment structure. Results also showed that vegetation cover markedly enhances surface resistance to wind erosion. Under different vegetation cover scenarios, the resistance of sandy and sandy gravel surfaces to wind erosion increased as the Dc value increased. (C) 2020 Elsevier B.V. All rights reserved.