为了选择适宜规格的纱网沙障进行流动沙地治理,在乌兰布和沙漠流动沙丘设置2 m×2 m,4 m×4 m,6 m×6 m网格或2 m,4 m,6 m带宽的带状纱网沙障,采用美国HOBO全自动风速风向仪测定其风速变化,并分析了地表粗糙度、相对风速和防风效能。结果 表明:2 m×2 m网格纱网沙障地表粗糙度随着风速增加而呈现出线性降低的规律; 纱网沙障主要是降低近地表30 cm以下高度的风速,并提高近地表粗糙度; 随着风速增加,纱网沙障防风效能变化总体呈现出降低的趋势。在流动沙丘设置2 m×2 m,4 m×4 m网格或2 m,4 m带状纱网沙障可有效降低近地表风速、增加地表粗糙度,总体防风效能较好。
In order to select suitable gauze sand barriers for control mobile sand, the effect of the gauze sand barrier on sand fixation was studied, and it's the impact on the characteristics of near-surface wind speed was evaluated. The 2 m × 2 m, 4 m × 4 m, 6 m × 6 m grid or 2 m, 4 m, 6 m belt gauze sand barriers were set up in the mobile dunes of Ulan Buh Desert, the wind speed change of the gauze sand barriers was measured by using the HOBO wind speed anemometer. The surface roughness, relative wind speed, and wind protection effectiveness were analyzed. The results showed that the surface roughness of 2 m × 2 m grid gauze sand barriers decreased linearly with increase of wind speed; the gauze sand barrier mainly reduced the wind speed at a height below 30 cm near the surface, and increased the surface roughness; with the increase of wind speed, the change of wind breaking efficiency of gauze sand barriers generally showed the decreasing trend. The 2 m×2 m, 4 m×4 m grids or 2 m, 4 m belt gauze sand barriers set up on the mobile dunes can effectively reduce the near-surface wind speed, increase surface roughness, which has the better windproof performance.
