干旱区生态环境知识资源中心

Under the influence of the properties of underlying surface, the wind-sand flow structure near the ground is different when the sandstorm occurs in different areas. In this paper, in order to explore the structure features of the wind-sand flow near the ground during a sandstorm in desertification grassland, Zhao He observation station at Inner Mongolia, China, in desertification grassland has been selected as an example. According to data measured by anemometer and sand collector, a comparative analysis on the relative sediment concentrations for different height in eight directions during the sandstorm on April 29-30, 2011, and study the pattern of wind-sand flow structure have been done. The result shows that the first-rank curve fitting of wind-sand flow structure is exponential function under the northwest (main direction of the sandstorm), and the sediment discharge were increased with the height increase. The wind-drift sand flows are mainly suspension in prevailing wind direction. In the southeast, the opposite to the prevailing wind direction, the first-rank curve fitting of wind-sand flow structure is power function that showed sediment discharge were decreased with height increase, and saltation is the main wind-drift sand flows movement pathway. In the rest directions, weak correlations between sediment discharge and height during a sandstorm have been found. The closer directions to the prevailing wind direction, the more relative sediment discharge in the elevations above 30-35cm.