A model of the sand transport rate that accounts for temporal evolution of the bed

Abstract

Aeolian sediment transport is influenced by a variety of bed surface properties. During wind erosion, the dynamic changes of many bed surface properties lead to dynamic changes of the sand transport rate. However, researchers often simplify their research by ignoring these changes, in part because the wind velocity is stable in a wind tunnel. This leads to an incomplete understanding of aeolian sand transport processes. In the present study, we quantified how the sand transport rate changes with increasing averaging time in a wind tunnel. We found that the average sand transport rate decreased with increasing wind erosion averaging time. This phenomenon had two causes: First, because the sand bed surface became increasingly rough during erosion, the wind's sediment transport capacity decreased. Second, the bed surface became increasingly coarse-textured as fine particles were removed by the wind, thereby decreasing sediment availability at the surface. Based on these experimental results, we established a new sand transport model that accounts for the effect of averaging time on the sand transport rate. We demonstrate the performance of the model using additional wind tunnel data.