Next Article in Journal
Geotourism and Local Development Based on Geological and Mining Sites Utilization, Zaruma-Portovelo, Ecuador
Next Article in Special Issue
Migration of Barchan Dunes in Qatar–Controls of the Shamal, Teleconnections, Sea-Level Changes and Human Impact
Previous Article in Journal
Response of Soils and Soil Ecosystems to the Pennsylvanian–Permian Climate Transition in the Upper Fluvial Plain of the Dunkard Basin, Southeastern Ohio, USA
Previous Article in Special Issue
Role of Aeolian Dust in Shaping Landscapes and Soils of Arid and Semi-Arid South Africa
Article Menu
Issue 6 (June) cover image

Export Article

Open AccessArticle
Geosciences 2018, 8(6), 204; https://doi.org/10.3390/geosciences8060204

Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China

1
Key Laboratory of Desert and Desertification, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
2
School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
3
Department of Geosciences, University of Cologne, 50969 Cologne, Germany
*
Authors to whom correspondence should be addressed.
Received: 4 May 2018 / Revised: 30 May 2018 / Accepted: 1 June 2018 / Published: 6 June 2018
(This article belongs to the Special Issue Aeolian Processes and Geomorphology)
Full-Text   |   PDF [4183 KB, uploaded 6 June 2018]   |  

Abstract

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 ≈ 2835 m2 s−1, and W0 ≈ 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 ≈ 1722 m2 s−1 and L0 ≈ 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. View Full-Text
Keywords: barchan dunes; China; Hexi Corridor Desert; dune migration rate barchan dunes; China; Hexi Corridor Desert; dune migration rate
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material

SciFeed

Share & Cite This Article

MDPI and ACS Style

Zhang, Z.; Dong, Z.; Hu, G.; Parteli, E.J.R. Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China. Geosciences 2018, 8, 204.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Geosciences EISSN 2076-3263 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top