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Journal of Desert Research ›› 2018, Vol. 38 ›› Issue (6): 1144-1152.DOI: 10.7522/j.issn.1000-694X.2017.00092

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Characteristics of Aeolian Sediment Flux Structure over Different Underlying Surfaces in Semi-arid Area

Yang Huan1, Li Yuqiang1, Wang Xuyang1,2, Niu Yayi1,2, Gong Xiangwen1,2, Yu Peidong3   

  1. 1. Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
    3. School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
  • Received:2017-10-27 Revised:2017-11-28 Online:2018-11-20 Published:2018-12-05

Abstract: Based on measured data from sand traps and weather station from April to May in 2017, aeolian sediment flux structure at 0-75 cm is analyzed over three typical types of underlying surface which included moving dune, semi-fixed dune and fixed dune in Korqin Sandy Land. The results showed:(1)The percentage of total sand transport flux decreased with the increase of height while the percentage of total sand transport flux increased with the increase of wind speeds, and 92.20%-95.60% of the total sand transport flux was distributed within the height 0-21 cm.(2)The total sand transport rate sequences are moving dune>semi-fixed dune> fixed dune. When both the total sand transport rate and the wind speeds at height of 200 cm are calculated through function fitting analysis, moving dune present the power function relation, and semi-fixed dune and fixed dune present the exponential function relation.(3)When both the sand transport rate at the each level and the wind speeds at height of 200 cm are calculated through function fitting analysis, the proposed power function of moving dune(R2 ≥ 0.9045) and semi-fixed dune(R2 ≥ 0.9681) is better than exponential function, and the exponential function of fixed dune(R2 ≥ 0.9230) is better than the power function.(4)At certain height, the sand transport rate of three types of sand dunes increases with the increase of wind speed. Under certain wind speed conditions, the sand transport rate decreased with the increase of the height.(5)The characteristic values of the three types of dunes with the increase of wind speed present a gradually increasing trend, moving dune(λ>1) still have the ability of erosion surface to continue transport sand particle; The semi-fixed dune showed a gradually weak erosion state when the wind speed was over 9.0 m·s-1. The the surface of fixed dune(λ<1) is mainly accumulated.(6)The three types of sand dunes are composed of fine particles from 0.1 mm to 0.25 mm, and the sediment yield is 50.09%-85.11% at the height of 0-30 cm, and the sediment yield is 43.53%-75.53% at the 30-75 cm height.

Key words: aeolian sediment flux structure, particle size distribution, sand transport rate, Korqin Sandy Land

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