Migration of barchan dunes and factors that influence migration in the Sanlongsha dune field of the northern Kumtagh Sand Sea, China

Yang, Zhuanling; Qian, Guangqiang; Dong, Zhibao; Tian, Min; Lu, Junfeng

doi:10.1016/j.geomorph.2021.107615

Cited by 15 publications

(18 citation statements)

References 32 publications

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“…Consequently, the dune number decreases rapidly, the volume of barchans and the inter-dune spacing increase in this stage (Figure 5b). As the evolution time continuously increases, the number of collisions between barchans decreases due to the further increased dune volumes and the reduced migration velocities of barchans (Bo & Zheng, 2013a; Z. L. Yang et al, 2021), which makes the dune number decrease at a small rate and tend to a stable state. Figure 5c shows the temporal evolution process of dune number density in barchan dune fields with different areas.…”

Section: Temporal Evolution Of Barchan Dune Number Densitymentioning

confidence: 99%

“…This is due to: first, the dune number density peak in barchan dune fields with small sand particle diameters appears earlier and the peak value is larger, thus, the interactions are more active within dune fields. Second, the wind field has strong erosion and transport capacity for sand particles with small diameters, resulting in a faster migration velocity of barchans when the sand particle diameter is small, which promotes dune interactions (Bo & Zheng, 2014; Groh et al., 2009; Z. L. Yang et al., 2021). Moreover, it can be seen from the figure that more interactions occur within a dune field as the sand particle diameter decreases, and the spatial density of interactions that cause a decrease in dune number density increases significantly, which results in a faster decrease in dune number density in the barchan dune field with small sand particle diameter.…”

Section: Dynamic Mechanism Analysismentioning

confidence: 99%

Section: The Environmental Factors Influence During the Decline Stage...mentioning

confidence: 99%

“…Therefore, the decay rate of dune number density gradually increases. When the value of H further increases to 0.95 m, a large number of barchans are connected with each other to form barchan dune chains due to the sufficient sand supply, causing an increase in the dune volume and a decrease in the migration velocity of barchans (Bagnold, 1941; Gay, 1999; Z. L. Yang et al., 2021), resulting in a decrease in spatial density of dune interactions. Therefore, the decay rate of dune number density decreases.…”

Section: Dynamic Mechanism Analysismentioning

confidence: 99%

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Temporal Evolution of Dune Number Density in a Barchan Dune Field

2023

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The present work examines the temporal evolution of dune number density in desert barchan dune fields and the effects of wind velocity, particle diameter and sand supply thickness using the Comprehensive Scale‐Coupled Model of dune field considering turbulence. Results show that the dune number density exhibits a temporal evolution trend of “increase—decrease—tend to be stable,” which is similar to the “overshoot” phenomenon of the per unit width sand transport rate evolving with time. The larger the wind velocity and the smaller the particle diameter are, the enhanced surface sand transport by wind causes the dune number density peak to be larger and appear earlier, but the more active dune interactions result in a higher decay rate during the decline stage. In addition, a small sand supply thickness slows sand accumulation and thus delays the initial development of barchans. With an increase in the sand supply thickness, more small‐scale barchans are formed earlier in dune fields due to gradually sufficient sand amounts, which promotes dune interactions and thus accelerates the decay of dune number density. Nevertheless, as the sand supply thickness continuously increases, the barchans link together to form dune chains, resulting in a slowed migration velocity and a reduced spatial density of interactions. The present work makes up for the lack of understanding of the initial evolution stage of barchan dune fields and the dune interactions in existing studies, and thus may be helpful for gaining insight into the dynamic evolution process of aeolian dune systems.

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Section: Temporal Evolution Of Barchan Dune Number Densitymentioning

confidence: 99%

Section: Dynamic Mechanism Analysismentioning

confidence: 99%

Section: The Environmental Factors Influence During the Decline Stage...mentioning

confidence: 99%

Section: Dynamic Mechanism Analysismentioning

confidence: 99%

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Temporal Evolution of Dune Number Density in a Barchan Dune Field

2023

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“…where U is the surface wind speed at 10 m above ground (m s À1 ) and U t is the wind speed threshold for initiating sand transport, set here at 6 m s À1 (Fryberger, 1979;Yang et al, 2021). From the daily scalar magnitude of DP and the u-and v-components of the wind, the vector direction of DP was calculated and averaged for each day.…”

Section: Sand Drift Potentialmentioning

confidence: 99%

Dune movement under climatic changes on the north‐eastern Tibetan Plateau as recorded by long‐term satellite observation versus ERA‐5 reanalysis

Dörwald,

Lehmkuhl,

Walk

et al. 2023

Earth Surf Processes Landf

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The movement of active dunes is tightly linked to climatic conditions (e.g., wind regime, temperature and precipitation) as well as human influence (e.g., grazing, dune fixation and greening). Dune migration rates can be studied to draw conclusions of changing wind conditions over time. The Gonghe Basin (GB), located on the north‐eastern Tibetan Plateau (TP), offers a good testing ground for these assumptions. The intramontane basin is highly influenced by two major wind regimes: the mid‐latitude Westerlies and the East Asian summer monsoon. To investigate environmental changes, this study combines optical remote sensing techniques with climatic datasets. High‐resolution satellite images of the last five decades, such as CORONA KH‐4B, are used to map dunes and calculate their respective migration rates. Further, height information was extracted as well. Climatic changes from the ERA‐5 reanalysis dataset and normalized difference vegetation index (NDVI) values were processed alongside. Relating the dunes' surface processes to climate model data shows an accordance between slowing migration, expanding vegetation and a decrease in sand drift potential. From 1968 to present time, an average dune migration rate of 7.3 m a−1 was extracted from the satellite images, with an overall reduction of −1.81 m a−1. The resultant drift potential (RDP) values for the GB are calculated to be below 10 m3 s−3 with a spatial decrease, following a direction from the NW to the SE, fitting well with a corresponding decrease in the migration rates. Our results indicate a good agreement between the development of aeolian landforms and the ERA‐5 climate reanalysis model data, even in a high‐altitude setting with complex topography, which is known to influence such datasets.

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UAV‐SfM‐based field quantification of barchan dune celerity and morphodynamics in Gonghe Basin

Shao,

Luo,

Che

et al. 2024

Earth Surf Processes Landf

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Barchan dunes do not often coexist with grasslands. However, in Gonghe Basin, north‐eastern part in Qinghai‐Tibetan Plateau (QTP), China, many barchan dunes are distributed on the grassland at high altitude. Identifying celerity and morphodynamics of barchan dunes and exploring the interaction between barchans and grassland landscape can help us better understand aeolian system sand mitigate damages. In this work, we tracked dune celerity and observed three‐dimensional changes of symmetrical and asymmetrical barchan dunes in Ertala based on high‐resolution UAV‐SfM reconstruction in short‐term monitoring and discussed the factors influencing dune celerity and deformation at high altitude. The results revealed that the barchan dunes are highly mobile with an average celerity of 0.85 m/M for the whole study area. Based on observations of dune morphology and dynamics, we found the following: (1) The dune deformation degree in a short time is not large but is widespread, especially in the elongated arm of asymmetric dune. The deformation of symmetric dune is symmetrical, whereas that of dune with extended horn is asymmetrical; (2) the sand supply, vegetation and airflow at low air density all influence the celerity and deformation degree in the development of barchan dunes; (3) the asymmetric airflow and sediment supply are important cause of dune asymmetry. The above results help us understand the deformation of barchan dune from the three‐dimensional, especially the difference reflected by the symmetry of barchan dune at high altitude.

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Migration of barchan dunes and factors that influence migration in the Sanlongsha dune field of the northern Kumtagh Sand Sea, China

Cited by 15 publications

References 32 publications

Temporal Evolution of Dune Number Density in a Barchan Dune Field

Temporal Evolution of Dune Number Density in a Barchan Dune Field

Dune movement under climatic changes on the north‐eastern Tibetan Plateau as recorded by long‐term satellite observation versus ERA‐5 reanalysis

UAV‐SfM‐based field quantification of barchan dune celerity and morphodynamics in Gonghe Basin

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