The linear sand transport processes in arid regions

Arid lands cover approximately 40% of Earth's land surface and experience significant aeolian hazards. Wind-driven sand transport drives agricultural desertification, dust storms, and other environmental impacts. Sand transport occurs across all land surface types in arid and semiarid regions, controlled by wind dynamics (shear velocity and turbulence) and surface characteristics (e.g., sand availability). Although well-studied above shifting sands, generalized transport models remain debated. This study investigates sand transport rate dependencies on shear velocity and transported mean grain size across five surfaces at the Tengger Desert margin (northern China): shifting sand, vegetated sand, degraded vegetation, agricultural land, and agriculture- agriculture transition zones. Field data test existing shear velocity-based models. Results indicated that sand flux follows exponential decay with height, consistent with prior studies; transported grain size differs significantly across surface types; transport rates (Q) show invariance with grain-size and saltation-height (zq); Q increases linearly with shear velocity and creep rates (q0); dimensionless transport rates scale linearly with measured rates and Shields numbers; impact entrainment explains observations more effectively (R2=0.91) than fluid mechanisms (R2=0.86), i.e., impact ultimately dominates transport. Current models systematically underestimate transport rates. Improved field studies across diverse arid landscapes are needed to advance predictive modeling.