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Journal of Desert Research ›› 2023, Vol. 43 ›› Issue (5): 194-203.DOI: 10.7522/j.issn.1000-694X.2023.00106

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Surface aerodynamic characteristics of flat quicksand in the middle reaches of Yarlung Tsangpo River

Ting Liu1,2(), Xiaopeng Jia1, Dingmei Chen3, Lamu Yixi3, Yan Zhang1,2, Kaijia Pan1,2, Zhengcai Zhang1,4()   

  1. 1.Key Laboratory of Desert and Desertification,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.Shannan Meteorological Bureau,Shannan 856000,Xizang,China
    4.School of Geography Science and Tourism,Shaanxi Normal University,Xi'an 710119,China
  • Received:2023-05-31 Revised:2023-07-14 Online:2023-09-20 Published:2023-09-27
  • Contact: Zhengcai Zhang

Abstract:

The near-ground aerodynamic process and characteristics are important factors affecting the process and intensity of wind-blown sand movement, which are influenced by a variety of factors such as surface roughness characteristics and air density, and are the important contents of the scientific research on wind-blown sand. The middle reaches of Yarlung Tsangpo River are one of the regions with the most frequent wind-blown sand activities in the Qinghai-Tibet Plateau, but the research on the surface aerodynamic process of shifting sand is relatively weak. Based on the field measured wind speed data of Shigatse wide valley and Shannan wide valley, this paper analyzes the wind speed profile, aerodynamic roughness (z0) and frictional wind speed (u*) of shifting sand surface, aiming to provide theoretical basis for the process and mechanism of high-altitude wind-blown sand movement, and provide ideas for the prevention and control of wind-blown sand disasters in this area. The results show that: (1) When the air density is 0.84±0.02 kg·m-3, the wind velocity profile on the surface of quicksand meets the logarithmic function. The mean intercept and slope of wind velocity profile at high altitude are greater than those at low altitude, indicating that air density caused by altitude affects near-ground air flow. (2) The friction wind speed in Yarlung Tsangpo River increases linearly with the increase of wind speed (R2> 0.75), but the fitting coefficient between the two is greater than the previous research results, which further indicated that the air density affected the near-formation airflow movement. (3) u* and z0 satisfy the exponential model z0=b1exp (u* / b2)+b3, which is different from previous field measured data and wind tunnel test results (2-parameter exponential model, etc.). (4) Under similar homogeneous underlying surface conditions, u* and z0 are significantly positively correlated with air temperature, humidity and altitude, and air temperature has the greatest influence.

Key words: Yarlung Tsangpo River, wind speed profile, friction wind speed, aerodynamic roughness length

CLC Number: