Abstract: Roughness elements can prevent the surface from wind erosion, and the aerodynamic effects of roughness elements are the foundation of understanding the mechanism of this protection. Shear stress and roughness length are the important aerodynamic parameters. Based on the published literatures, the research progress on two approaches of drag partition and roughness length of the surface with roughness elements in the past half century was reviewed and analyzed. One approach of drag partition was related to the roughness density, and the other was related to roughness length. However, it was not easy to estimate the parameters of both approaches. The study of roughness length was put into two periods. How to simulate the heterogeneous and complex surfaces with roughness elements is still a big challenge. In order to find the solution of this problem, we considered the remote sensing technology to be as a mean to estimate the roughness length for large regions where the roughness length cannot be obtained by other means.

Key words: roughness element, shear stress, aerodynamic effect, roughness length, remote sensing monitoring