Coexistence of Two Dune Growth Mechanisms in a Landscape‐Scale Experiment

Lü, Peng; Narteau, C.; Dong, Zhibao; Claudin, Philippe; Rodríguez, S.; An, Zhishan; Gadal, Cyril; Pont, Sylvain Courrech du

doi:10.1029/2021gl097636

Cited by 8 publications

(5 citation statements)

References 57 publications

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“…The predicted orientation for elongating dunes is in good agreement with experiments on centimetric sand bedforms under water [41], numerical simulations [64] and field measurements [226] for bimodal flow regimes. This rule also correctly predicts the multiple directions of elongation observed for star dunes on a starved bed in numerical simulations when the flow regime is multidirectional with a null RDP [90].…”

Section: Elongation Without Migrationsupporting

confidence: 78%

Complementary classifications of aeolian dunes based on morphology, dynamics, and fluid mechanics

Courrech du Pont,

Rubin,

Narteau

et al. 2024

Preprint

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Dunes form where winds blow over a bed of mobile sediment grains – conditions that are common in our solar system. On Earth, dunes abound in arid continental interiors and along sandy coastlines. Dune fields have also been recognized on other planetary bodies, including Venus, Mars, Saturn’s moon Titan, and Pluto. Despite the relatively basic conditions required for their formation, dunes adopt a rich diversity of shapes, sizes, and behaviors in response to their boundary conditions and other environmental forcings. Thus, people around the globe and over centuries have developed a rich vocabulary to describe dunes and their complexity. In addition, many studies have been devoted to link dune shape to environmental forcings, usually by means of correlations. As a result, existing dune nomenclature often includes redundant terms with differing definitions across scientific communities. Although a worthy first step, correlation-based classifications can be misleading if not based on an underlying mechanics and if dune morphogenetic classes are not uniquely defined. Here, we synthesize existing dune terminology and put the last two decades of research on dune morphodynamics in perspective in proposing three simplified dune classification schemes based on the state-of-the-art understanding of dune morphology, morphogenetic processes and coupling between sand bed, fluid flow and sediment transport. Together, these classifications provide a unified framework for geomorphologists, sedimentologists, geographers, physicists, and others to describe windblown sand dunes on Earth and beyond through their shape, dynamics, and size as a response to winds and boundary conditions.

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Section: Elongation Without Migrationsupporting

confidence: 78%

Complementary classifications of aeolian dunes based on morphology, dynamics, and fluid mechanics

Courrech du Pont,

Rubin,

Narteau

et al. 2024

Preprint

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“…The sand supply thickness (sand availability) is often used to characterize the amount of sand that is available for transport present on the ground, and is an important environmental factor affecting the morphodynamics of sand dunes and the evolution of aeolian dune field patterns (Eastwood et al., 2011; Lv et al., 2022). Existing studies revealed that the sand supply thickness and wind direction together determine the morphological characteristics of dunes (Bo & Zheng, 2011; Courrech du Pont et al., 2014; Wasson & Hyde, 1983).…”

Section: Discussionmentioning

confidence: 99%

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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“…Robson & Baas, 2023) are also limited (e.g. Lü et al, 2022). The Gonghe Basin is located on the north‐eastern margin of the Qinghai‐Tibet Plateau (QTP; Figure 1), the north‐western edge of the Asian monsoon region, at an altitude of 3400 m (Liu et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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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Coexistence of Two Dune Growth Mechanisms in a Landscape‐Scale Experiment

Cited by 8 publications

References 57 publications

Complementary classifications of aeolian dunes based on morphology, dynamics, and fluid mechanics

Complementary classifications of aeolian dunes based on morphology, dynamics, and fluid mechanics

Temporal Evolution of Dune Number Density in a Barchan Dune Field

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

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