The dynamical processes of a typical linear dune including morphological features, dune ridge swing range and crest height were investigated at different monitoring periods in the hinterland of Tengger Desert. The results indicated that the development of linear dune depends on not only the northwesterly prevailing wind, but also the winds from northeast and southwest. The dune ridge swayed along its fundamental strike and took on an eastward movement gradually. The original dune strike was NW70° on August 3, 1994, and then changed to NE15° on April 21, 2001. The dune crest increased by 1.8 m longitudinally, which manifested strong wind-blown sand activities in this region. Wind erosion frequently occured at the bottom of sand dune, while sand accumulation appeared on its mid-upper section. The mean wind erosion depth was 25 cm on the bottom of linear dune and the height difference of the control points on the dune's ridge was 1.13 m. Although the linear dune swayed laterally, the horizontal displacement of its ridge moved eastward 5.8 m averagely. The swing range of the dune crest line is very distinct, with a maximum value of 13.2 m. The highest site on the K-profile swayed on both sides of the dune ridge and the heights were 19.88 m at the control point K5, 19.61 m at K6 and 19.05 m at K7, respectively. The results indicated that the lateral swing of the linear dune was distinct under the northwesterly wind and it moved toward east gradually.
Sand damages along the Qinghai-Tibet Railway occur frequently and have spread rapidly since it was completely opened to traffic in 2006.The goal of this study was to understand the effects of sand damages on the railway via meteorological data and in situ observation of wind-blown sand.We selected the Tuotuohe section of this railway as a typical research object,and we systematically investigated its characteristics of sand damages,drift potential,sand-driving wind rose,and their time variation.The direction of sand-drifting wind clearly varies with the season.In winter,the predominant wind blows from the west and lasts for three months,while in summer the frequency of northeasterly wind begins to increase and multi-directional winds also occurs in July.The drift potential in this area is 705.81 VU,which makes this a high-energy wind environment according to Fryberger's definition.The directional variability (RDP/DP) is 0.84 and the resultant drift potential is 590.42 VU with a resultant direction of 89.1°.
KeCun Zhang QingHe Niu JianJun Qu ZhengYi Yao QingJie Han
