摘要
通过对腾格里沙漠腹地典型线性沙丘进行了三期定点监测,结合周边区域风况资料,从沙丘的形态特征、年摆动幅度及其监测断面的高程分布等对其形成环境及动力过程进行了研究。线性沙丘纵向年增高幅度达1.8 m,沙丘底部平均吹蚀深度达25 cm,脊线监测点高差可达1.13 m。沙丘底部风蚀现象比较严重,中上部位主要以积沙为主。该沙丘围绕主体走向向东摆动,沙丘脊线整体向东水平摆动距离达5.8 m。特别是沙丘顶部摆动幅度尤为明显,最大摆动幅度达到13.2 m。在沙丘K监测断面上,沙丘脊线西侧各控制点的高程呈减小趋势,沙丘主体向东侧摆动。从三次不同时期沙丘纵剖面控制点高程变化和横剖面K监测断面摆动特征来看,该线性沙丘除了受优势风向偏西风的影响外,还受东北风和西南风两股风的牵制,表现为沙丘脊线围绕主体走向左右摆动,整体向东侧平移。
The goal of this paper is to reveal the formative environments and dynamic process of linear dunes in hinterland of Tengger Desert,based on the three monitoring data and regional wind regime.The dynamic variation of linear sand dunes will be illustrated from the aspects of the morphological characteristics,swing amplitude and the distribution of the control post＇s height on monitoring profile.It can be found that the development of linear sand dune depends not only on the northwesterly prevailing wind direction,but on the restriction of wind from northeast and southwest in terms of the control post＇s height along longitudinal profile and the swing amplitude of K cross section.The ridge of linear sand dune sways left-rightward beside its fundamental strike and takes on an eastward movement averagely.The primeval strike of the linear sand dune was NW70° on August 3rd in 1994,and then changed to NE15° on April 21st in 2001.The peak height of the linear sand dune increased to 1.8 m longitudinally,which reveals great wind-blown sand activities in this region.Wind erosion frequently occurs on the bottom of sand dune,while sand accumulation characterizes on its mid-upper section.The mean aeolian depth is 25 cm on the bottom of linear sand dune and the difference in height of the control post reaches to 1.13 m on the sand＇s ridge.Although linear sand dune sways on the both side of its main strike,the horizontal displacement of its ridge moved 5.8 m eastward averagely.Especially for the crest of linear sand dune,swing amplitude is very distinctly with the most value of 13.2 m.The height of control post in the K profile to the west side of sand dune＇s ridge began to increase in the afterward observation.The highest site in the K profile sways on the both sides of sand dune＇s ridge and its height is 19.88 m at K5,19.61 m at K6 and 19.05 m at K7 irrespectively during the three observations.Aforementioned variation sufficiently shows the lateral swing of linear sand dune is distinct on the northwesterly prevailing wind direction and takes an eastwardly displacement trend.
出处
《干旱区地理》
CSCD
北大核心
2010年第3期340-345,共6页
Arid Land Geography
基金
国家自然科学基金(40701171)项目资助
关键词
线性沙丘
腾格里沙漠
动力过程
linear sand dune
Tengger Desert
dynamic process
