Quick Search:       Advanced Search
Field determination for roughness length above the different non-erodible surfaces
Received:August 23, 2016  Revised:October 30, 2016  Click here to download the full text
Citation of this paper:HeQiang Du,Tao Wang,Xian Xue,2017.Field determination for roughness length above the different non-erodible surfaces.Sciences in Cold and Arid Regions,9(1):67~77.
Hits: 316
Download times: 410
Author NameAffiliationE-mail
HeQiang Du Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China dilikexue119@163.com 
Tao Wang Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China  
Xian Xue Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China  
基金项目:This work was financial supported by the Nature Science Foundation of China (Grant Nos. 41601009, 41401645), and the Open Fund of Yellow River sed-iment key laboratory of Ministry of Water Resources of China (Grant No. 2015004).
 
Abstract:Non-erodible elements, for its disturbance to the near-surface airflow, have been widely used in arid and semi-arid regions to protect the surface from wind erosion. Roughness length was usually used to evaluate the protection effect of non-erodible elements from wind erosion. In this study, the wind profiles above five types of non-erodible surfaces including gravel, wheat straw checkerboard barriers, cotton stem checkerboard barriers, shrubs, and herbs were measured and analyzed. The wind velocities above these surfaces increased with height approximately in logarithmic functions. The roughness length of different non-erodible surfaces was calculated by the functions of wind profiles. The results reveal that:(1) Roughness length increased with wind velocity in given wind velocity ranges. (2) On vegetative surfaces, wind did not effectively bend the stems. The threshold wind velocity for bending the stems of Achnatherum splendens was 4 m/s, 10 m/s for Agropyron cristatum, and for Artemisia ordosica, no obvious bending of stems even for wind velocity reaching 12 m/s. (3) Correlation analysis results show that the vegetation's coverage and frontal area affect the roughness length more significantly than the other parameters. (4) The protective results of these non-erodible elements were evaluated. The checkerboard sand barriers made of cotton stem could provide more effective protection than that made of wheat straw. In the same coverage conditions, vegetation could provide more effective protection from wind erosion than gravel, and the blending of different non-erodible elements especially the combination of blending of vegeation and checkerboard sand barriers could provide more effective protection to the surface.
keywords:non-erodible elements  wind velocity  wind erosion  protective results
HTML  View Full Text  View/Add Comment  Download reader