The Migration Process Of Aeolian Sand In Ulanbuh Desert Along The Bank Of The Yellow River, Deng Kou

Three kinds of typical models of underlying surface along the Yellow River in Ulan Buh Desert was studied by means of continuous spot observation and inner experiment, which focused on the basic situation of the soil particle, the environmental of wind energy, the structure of Wind-Sand movement of different underlying surface, the dust fall behind the desert, the morphological characteristics and the movement feature of sand dunes. The result could reveal the morphological changes and the movement feature of sand dunes, providing scientific decision-making basis for the prediction of the sediment yield of the Yellow River. The result showed that:The composition of sand particles in different underlying surface was different. The grassland was mainly in clay and silt, but the farmland and the sandy land were in very fine sand and fine sand. With the increase of soil profile, the clay and the silt of the grassland was increased and fine sand was decreased, while the farmland was on the contrary. The fractal dimension was the grassland>the farmland>the sandy land, it indicated that the fractal dimension of grass-shrub vegetation is bigger than the farmland and the sandy land. The practical size of the surface of the sand is fine than in the hinterland of desert, but mainly in fine sand, which the top was the thickest, the bottom of upwind was the finest.The dust fall was 5.03kg/m2 and mainly dominated by fine sand. Fine sand is gradually reduced with the increase of the distance. Silt and very fine sand are increased rapidly with the increase of the distance. The growth rate of 0.5m was well above 2m.The backdraft was begin at 3H. The dust fall of Ulan Buh Desert is mainly from the local material, and the proportion of material from the far sources and regional material was small.The annual mean wind speed was 3.7m/s and mainly within 10m/s. The critical threshold wind velocity was 5m/s(of 2m), also mainly in March to May and the main wind direction was SW-W. The change of wind speed from the interdune lowland to the leeward slope was follow the trend of parabola. The sediment load of different underlying surface were different, but the amount of the sediment load was Mobile dune> Fixed dune>farmland> semi-fixed sand dune>grassland, the sediment load was power function decreasing with height except the grassland. The movement of sand dunes was greatly influenced by the monsoon and had no regularity. The sand dunes movement was mainly in March to May when more southwest wind, and moved 19.45 m in five years with fast one-way transport. The amount of movement of typical dune was 897.56m3-1305.29m3, the sediment load was 29.011 t/m·a-22.443 t/m·a(2012-2013). The sand dunes movement was significant positive correlation with the wind direction of W, WNW and negative correlation with the dune height. In general the sand dunes moved eastward toward the southeast.