西沟孔兑下垫面特征及风沙输移规律研究

The ten major Kongdui in the upper reaches of the Yellow River pose a serious threat to the ecology of the Yellow River and the development of the surrounding areas.Through the sample survey,the type of the underlying surface was divided and the sand collecting instrument and HOBO small data collection instrument were used to observe the sand transport volume,wind speed and wind direction of each underlying surface,and the wind and sand area of Xiliugou,one of the ten major Kongdui,were studied,and the characteristics of different underlying surfaces and the law of aeolian sand transport in the area were explored,which provided a reference basis for the protection and treatment of similar river basins.The results showed that:(1)The underlying surface of the Xiliugou hole to aeolian sand area was divided into flowing sand,semi-fixed sand and fixed sand,and the area,length and width of the riverbed of the flowing sand were higher than that of fixed and semi-fixed sand.(2)The prevailing winds in the study area were all southwest winds,and the main harmful winds were northwest winds;Moreover,the change of wind speed near the ground showed an increasing trend with the increase of the height from the surface.(3)In the same underlying surface type,with the increase of the height from the surface,the sand transport rate showed a decreasing trend.When there are different underlying surfaces,due to the different surface roughness,the sand transport rate at the same surface height is also different,and it also shows a trend of reduction,indicating that the surface roughness has a certain hindering effect on the movement of sand grains.