Advances in Earth Science ›› 2021, Vol. 36 ›› Issue (1): 95-109. doi: 10.11867/j.issn.1001-8166.2021.009

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Form-flow Feedback within Blowouts at Different Developing Stages in the Gonghe Basin, Qinghai Province

Xuehua CHE 1 , 2( ), Wanyin LUO 1( ), Mei SHAO 1 , 2, Zhongyuan WANG 3   

  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.Beijing Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China
  • Received:2020-10-29 Revised:2020-12-09 Online:2021-03-19 Published:2021-03-19
  • Contact: Wanyin LUO;
  • About author:CHE Xuehua (1997-), female, Lüliang City, Shanxi Province, Master student. Research areas include aeolian geomorphology and physics of blown sand. E-mail:
  • Supported by:
    the National Natural Science Foundation of China "Mega-blowouts formation and its response to the environmental change"(41771015)

Xuehua CHE, Wanyin LUO, Mei SHAO, Zhongyuan WANG. Form-flow Feedback within Blowouts at Different Developing Stages in the Gonghe Basin, Qinghai Province[J]. Advances in Earth Science, 2021, 36(1): 95-109.

Blowouts are the primary geomorphologic manifestation and driving force of sandy grassland desertification in the Gonghe Basin. However, their feedback mechanism between the flow dynamics and geomorphology is unclear. Two-dimensional ultrasonic anemometers and gradient sand traps were used in this study to measure the characteristics of wind flows and sediment transport at different blowouts of different developing stages in the Gonghe Basin. The feedback between the morphology-dynamic processes of the blowouts was discussed. Results show as follows. After entering the sand patch and small bowl blowout along the prevailing wind direction, air flow expanded and decelerated, and then accelerated until going outside the blowout; when entering a trough blowout of a small or medium size, it expanded and decelerated at the headwall, accelerated at the bottom of blowout, decelerated at the windward slope of the depositional lobe, and then recovered somewhat at the leeside slope of the depositional lobe. Besides, the wind speed was negatively correlated with steadiness of flow and directional steadiness in the early stage of blowout, but was positively correlated with the steadiness of flow and negatively correlated with the directional steadiness in the middle stage of blowout. Due to the rotating vortices in the blowout, the wind speed profiles in the trough blowout displayed a nonlogarithmic behavior. The measured sand flux density at different stations decreased exponentially with height. However, due to the feedback effect between flow dynamics and morphology, the sediment transport fluxes at different positions were obviously different, with the lowest at the bottom of the blowout and the largest in front of the windward slope of the deposition lobe. In conclusion, there is a form-flow feedback in the blowout, and the bigger the blowout is, the more obvious the feedback effect is.

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