库布齐沙漠南缘抛物线形沙丘表面风速与输沙率的变异  

Variation of Surface Wind Velocity and Sand Transport of Parabolic Dune at Southern Fringe of the Hobq Desert

作　　者：陶彬彬[1] 哈斯额尔敦[1] 乌格特茉勒[1] 管超[1] 

机构地区：[1]北京师范大学资源学院,北京100875

出　　处：《中国沙漠》2015年第6期1445-1452,共8页Journal of Desert Research

基　　金：国家自然科学基金项目(41171002);国家"十二五"科技支撑计划项目(2012BAD16B02)

摘　　要：以库布齐沙漠南缘典型抛物线形沙丘为研究对象,选取3个沙丘前端活动区的纵断面和一个贯穿两翼及翼间平地的横断面,同步观测各个断面的风速与输沙率,讨论抛物线形沙丘表面形态-动力学过程。结果显示,沙丘前端活动区3个纵断面的风速和输沙率遵循一般变化规律,即沿迎风坡上升逐渐增加,至丘顶及附近达到最大,并在背风侧降低;二者在3个纵断面上的变化趋势一致,但具体变化形式不同,沙丘表面动力与输沙过程存在较大的空间异质性。沙丘两翼具有纵向沙丘的动力学性质,翼体两侧风速和输沙率具有对称性。该沙丘沙源匮缺,前端活动区主要依靠两翼内侧侵蚀提供沙源。受沙丘形状和植被等因素影响,坡脚及坡下部风速与输沙率之间没有相关性,因此简单的风速放大率和输沙率变化程度无法准确揭示该类型沙丘表面复杂的形态-动力学关系。In the present study,we focused on a typical parabolic dune at the southern fringe of the Hobq desert to discuss the dynamic process acting on this type dune.We selected three longitudinal sections at the dune head which is active and one cross section traversing the two arms and the deflation basin between the arms.The wind velocity as well as sediment transport rate were observed simultaneously.At those three longitudinal sections,wind velocity and sediment transport rate increase with rising elevation along the stoss slope.Besides,the wind velocity and sediment transport rate reach their peaks near the crest,then reduce at the leeward slope between the crest and brink.It was found that the change trend of wind velocity and sediment transport rate at the three sections is similar,while their change modes are varied significantly.In a word,there is distinct spatial heterogeneity of the flow and sediment transport process on parabolic dune.When flow blows obliquely into the dune,the arms of parabolic dune are considered to have dynamic properties of longitudinal dunes.The wind velocity and sediment transport rate of two flanks of each arm are symmetric respectively.Sand source for this dune is limited and mainly comes from erosion of inner flank of its arms.Influenced by factors like special dune shapes and vegetation anchoring on and around the dune,mean wind velocity has almost no correlation with sediment transport rate at the toe as well as the lower part of slopes.Therefore,simple fractional speed-up ratio and sediment transport rate change between crest and toe are not effective and accurate to reveal the sophisticated morphodynamics of parabolic dunes.

关 键 词：抛物线形沙丘 风速 输沙率 库布齐沙漠 

分 类 号：P931.3[天文地球—自然地理学]