Numerical Simulation on Sand Fixed Effect of Shrub Belts and Straw Checkerboard Barriers

WANG Wan-fu~(1,2), SHEN Yan-bo~1, WANG Tao~1, SHEN Zhi-bao~1, DU Ming-yuan~3(1.Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730000;2.The Conservation Institute of Dunhuang Academy,Dunhuang, Gansu 736200;3.National Institute for Agro-environmental Science,305-8604,Tsukuba, Japan)

shrub belts;straw checkerboard barriers;sand fixed effect;numerical simulation

Combining Mesoscale Model (MM5) and Shaos wind erosion scheme, numerical simulation on sand fixed effect of shrub belts and straw checkerboard barriers were conducted on the top of the Mogao Grottoes. The study results show: building the shrub belts can make threshold shear velocity reach 1.15 m/s, which is 4.1 times of the value of unsetting of the shrub belts. The transport sand mass and dust-driving mass all reduce zero, meaning the erosion and transport sands almost inhabit. Setting straw checkerboard barriers can make shear velocity reach 0.53 m/s, which is 1.9 times as little as the value of unsetting of the straw checkerboard barriers. Q and F decrease 3/5 and 7/8 respectively, which mean fixed sand effect apparent. Generally, the shrub belts have better sand-fixed effect than that of straw checkerboard barriers. The friction velocity simulated by MM5 and observed in field have a good linear correlation, the coefficient could reach more than 0.8, meaning the results are credible by MM5 simulating friction velocity in the region.