干旱区生态环境知识资源中心(Arid): Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China

Arid

DOI	10.3390/geosciences8060204
	Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China
	Zhang, Zhengcai; Dong, Zhibao; Hu, Guangyin; Parteli, Eric J. R.
通讯作者	Zhang, ZC
来源期刊	GEOSCIENCES
EISSN	2076-3263
出版年	2018
卷号	8 期号:6
英文摘要	Crescent-shaped barchan dunes often display an asymmetric shape, with one limb longer than the other. As shown in previous studies, asymmetric bimodal winds constitute one major cause of barchan asymmetry, but the heterogeneous conditions of sand availability or flux, as well as topographic influences, may be also important. Understanding the morphology and dynamics of asymmetric barchans may have an impact in a broad range of areas, particularly as these dunes may serve as a proxy for planetary wind regimes and soil conditions in extraterrestrial environments. However, in addition to the existing theories and numerical models that explain barchan asymmetry, direct measurements of migration rates and morphologic changes of real asymmetric barchans over a time span of several years would be beneficial. Therefore, here we report such measurements, which we have acquired by investigating asymmetric barchans in the Hexi Corridor, northwest of China. We have found that dune interactions and asymmetric influx conditions are the most important causes of barchan asymmetry in this field. Particle size distributions in the Hexi Corridor display strong variations over different parts of the asymmetric barchans, as well as over different dunes, with gravel particles being incorporated from the substrate as the dunes migrate. Our observations have shown that upwind sediment sources are important for dune formation in the Hexi Corridor, and that interdune interactions affect dune shape in different ways, depending on their offset. The asymmetric barchans in the Hexi Corridor are active, with an average migration rate (MR) between 8 and 53 m year(-1), in spite of the different asymmetric shapes. Our data for dune migration rates can be described well by a scaling of MR = A/(W + W0), where W is the barchan cross-wind width, A approximate to 2835 m(2) s(-1), and W0 approximate to 44 m. A similar scaling fits very well the migration rate as a function of dune along-wind width L, (i.e., MR = B/(L + L0), with B approximate to 1722 m(2) s(-1) and L0 approximate to 13 m). Linear relations are also found between both dune widths and the average limb and windward side lengths, thus indicating that the morphometric relations that are predicted from models for steady-state, symmetric crescent-shaped dunes can be applied to different transitional morphologies of interacting, asymmetric barchans.
英文关键词	barchan dunes China Hexi Corridor Desert dune migration rate
类型	Article
语种	英语
开放获取类型	DOAJ Gold
收录类别	ESCI
WOS记录号	WOS:000436131300016
WOS关键词	GRAIN-SIZE CHARACTERISTICS ; SOLITARY WAVE BEHAVIOR ; SAND DUNES ; FLUME EXPERIMENTS ; SPATIAL-ANALYSIS ; PARABOLIC DUNES ; WESTERN DESERT ; SEIF DUNES ; TRANSVERSE ; MODEL
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
Scopus学科分类	Shaanxi Normal Univ, Sch Geog & Tourism, Xian 710119, Shaanxi, Peoples R China.
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/332841
作者单位	[Zhang, Zhengcai; Hu, Guangyin] Chinese Acad Sci, Northwest Inst Ecoenvironm & Resources, Key Lab Desert & Desertificat, Lanzhou 730000, Gansu, Peoples R China; [Dong, Zhibao] Shaanxi Normal Univ, Sch Geog & Tourism, Xian 710119, Shaanxi, Peoples R China; [Parteli, Eric J. R.] Univ Cologne, Dept Geosci, D-50969 Cologne, Germany
推荐引用方式 GB/T 7714	Zhang, Zhengcai,Dong, Zhibao,Hu, Guangyin,et al. Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China[J],2018,8(6).
APA	Zhang, Zhengcai,Dong, Zhibao,Hu, Guangyin,&Parteli, Eric J. R..(2018).Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China.GEOSCIENCES,8(6).
MLA	Zhang, Zhengcai,et al."Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China".GEOSCIENCES 8.6(2018).