摘要
干涸湖盆是干旱与半干旱地区沙尘暴的主要策源地。长江源地区卓乃湖流域湖泊溃堤后,大量湖底碎屑物质出露地表成为新的沙源,不断加剧的风沙灾害严重威胁着卓乃湖的生态环境与青藏铁路的安全运营。通过对卓乃湖西岸、南岸和东侧3个部位的风沙活动进行系统观测,获得了卓乃湖溃堤后地表及风沙流中沙尘物质的粒度分布以及风沙流结构。结果表明:卓乃湖西岸是流域内风沙活动最为强烈的区域,西岸和南岸是流域内的主要起沙起尘区;东侧为沉积沉降区,风沙沉积物既包括本地沙物质,也包含来自西岸和南岸的沙尘;由于湖相沉积物粒度较细,西岸的风沙流结构随高度线性递减。结合地表和风沙流中沙尘的粒度分析特征,认为卓乃湖流域沙尘以流体起动为主,而非传统观点认为的以跃移物质的轰击起动为主。高原地区干涸湖盆的风沙活动具有独特性,在风沙防治中不可照搬低海拔地区的防治模式。
The dry lake basin is one of the main sources of sandstorms in arid and semi-arid areas.With the burst of Zuo Lake in the source region of the Yangtze River,a large number of fragmentary materials from the lake bottom was exposed to the surface and became the new source of sand.The increasing sand storm disaster seriously threatened the ecological environment of Zuo Lake Basin and the safe operation of the Qinghai-Tibet Railway.In this paper,the grain size distribution and aeolian-sand flow structure of surface and aeolian-sand sediments after levee breach of Zuo Lake were obtained through systematic observation of aeolian-sand activities in three typical parts of west bank,south bank and east side of Zuo Lake.The results show that the west bank of Zuo Lake is the most intense area of sand activity in the basin,and the west bank and the south bank are the main source of sand and dust areas in the basin.The east side is the sedimentation area,and its blown sand sediments include both local sand materials and the dust from the west bank and the south bank.Due to the fine grain size of lacustrine sediments,the sand flow structure of west bank decreases linearly with height.Combined with the grain size results of surface and aeolian-sand flow sediments,it is speculated that the sand and dust initiation in Zuo Lake Basin is mainly aerodynamic entrainment,rather than the saltation bombardment as traditionally believed.The characteristics indicate that the aeolian sand activity in the dry lake basin in the plateau region is unique,and the prevention and control mode of low altitude areas cannot be copied in the prevention and control of aeolian-sand.
作者
范亚伟
杜鹤强
卢善龙
韩致文
刘秀帆
刘欣雷
Fan Yawei;Du Heqiang;Lu Shanlong;Han Zhiwen;Liu Xiufan;Liu Xinlei(National Key Laboratory of Ecological Security and Sustainable Development in Arid Area,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Digital Earth,Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China)
出处
《中国沙漠》
CSCD
北大核心
2023年第3期47-56,共10页
Journal of Desert Research
基金
第二次青藏高原综合科学考察研究项目(2019QZKK0202)
国家重点研发计划项目(2020YFA0608402)。
关键词
卓乃湖流域
干涸湖盆
粒度分布
风沙流结构
沙尘起动方式
Zuo Lake Basin
dry lake basin
particle size distribution
aeolian-sand flow structure
dust entrainment mode
