干旱区研究

干旱区研究 ›› 2021, Vol. 38 ›› Issue (4): 1058-1064.doi: 10.13866/j.azr.2021.04.17

• 天气与气候 • 上一篇    下一篇

玛曲高寒草甸风沙环境与沙化类型研究

安志山1,2(),史博源3,谭立海1,张凯3,张克存1()   

  1. 1.中国科学院西北生态环境资源研究院,沙漠与沙漠化重点实验室,敦煌戈壁荒漠生态与环境研究站,甘肃 兰州 730000
    2.中国科学院大学,北京 100049
    3.兰州交通大学创新创业学院,甘肃 兰州 730070
  • 收稿日期:2021-01-06 修回日期:2021-04-23 出版日期:2021-07-15 发布日期:2021-08-03
  • 通讯作者: 张克存
  • 作者简介:安志山(1986-),男,高级工程师,博士研究生,主要从事风沙灾害与防沙工程研究. E-mail: an1986wen@163.com
  • 基金资助:
    国家重点基础研究发展计划“高寒湿地、草地生态系统演变及草地沙化过程与机理”(2017YFC0504801);国家自然科学基金 “垭口、山前丘陵地段风动力环境与敦格铁路沙害形成机理研究”(41871016)

Sand environment and type during sandy desertification of an alpine meadow

AN Zhishan1,2(),SHI Boyuan3,TAN Lihai1,ZHANG Kai3,ZHANG Kecun1()   

  1. 1. Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Key Laboratory of Desert and Desertification, Dunhuang Gobi and Desert Research Station, Lanzhou 730000, Gansu, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
    3. Innovative Entrepreneurship Institute, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China
  • Received:2021-01-06 Revised:2021-04-23 Online:2021-07-15 Published:2021-08-03
  • Contact: Kecun ZHANG

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摘要：

玛曲县高寒草甸沙化是青藏高原地区发生沙化的典型案例,其成因、趋势和治理一直受到极大关注。利用三维激光扫描仪,结合野外监测和室内分析等方法,揭示了区域风沙环境,结合区域沉积物粒度与形态特征,依据沙物质来源复杂程度将沙化类型划分为风蚀坑沙化类型和复杂沙化类型。结果表明:区域全年输沙势为164.34 VU,合成输沙势为91.57 VU,合成输沙方向132.37°,风向变率0.56,属于中比率低风能环境。综合风蚀坑沙化类型周边风蚀坑与积沙区的长度比、体积比、长轴线、与区域主风向吻合程度及沉积物粒度特征,可知风蚀坑是该沙化类型区域积沙的主要贡献者。在现代沙化过程中,复杂沙化类型除周边风蚀区、活化沙丘以及沙化草地等为区域积沙贡献沙物质外,黄河河道也为区域积沙提供一定量的沙物质。

关键词: 玛曲, 高寒草甸, 三维激光扫描仪, 沙化过程, 形态参数

Abstract:

Alpine meadow desertification in Maqu County is a typical case of desertification in the alpine and humid regions of China. The causes, trends, and management of desertification have received considerable attention; however, due to the limitations of research methods and other factors, the precise positioning of sand sources is still unclear. Here, we combined a three-dimensional laser scanner with traditional methods, such as field surveys and indoor analysis, to locate sand sources accurately from a morphological perspective. The results showed that the regional annual sand drift potential was 164.34 VU, synthetic sand transport potential was 91.57 VU, synthetic sand transport direction was 132.37°, and wind direction variability was 0.56, which belonged to a medium-ratio low wind energy environment. According to the complexity of the contribution of regional sand material, this paper further subdivides the sandy zone along the Yellow River into two types: blowout desertification and complex desertification. The blowout desertification was characterized by isolated sand dunes with a slightly smaller area and wind erosion blowout in the upwind direction. The long axis direction was highly consistent with the regional main wind direction, the length ratio of the wind erosion area and sand accumulation area, volume and other morphological parameters, and the special diagnosis of sand material particle size. The desertification process was relatively simple. Also, the sand material mainly came from wind erosion blowout. The complex desertification area was larger than the blowout desertification area. The causes of desertification include dune activation, regional wind erosion, thermal melt slump. The sources of dune material include surrounding activated dunes, wind erosion land, desertified grassland. Compared with the former, the sand source of complex desertification was relatively wide, and the desertification process was complex and diverse. In modern desertification, the wind-eroded depressions around the region were still the main contributors of sand accumulation in the complex desertification type. At the same time, the Yellow River also provides some amount of sand material for regional desertification.

Key words: Maqu country, alpine meadow, 3-D laser scanner, sandy desertification, morphology