Wind Ripples

Sharp, Robert P.

doi:10.1086/626936

Cited by 327 publications

(424 citation statements)

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“…At high wind velocities, by comparison, aeolian sand flow is large enough to attain the full development stage on a short bed (Andreotti et al, 2010). This phenomenon further confirms that splashing processes and creeping (reptation) sand play important roles in the formation and evolution of aeolian sand ripples (Sharp, 1963;Anderson, 1987;Anderson and Haff, 1988;Rice et al, 1995;Rioual et al, 2000;Durán et al, 2014).…”

Section: Differences In Sand Ripples Along the Bed Surfacesupporting

confidence: 75%

“…Ripple height of sand ripples initially increases with wind velocity and decreases after wind velocity reaches a certain value (Bagnold, 1941;Li and Ni, 2004;Zhu, 2009). Ripple height of coarse grains is greater than that of fine grains (Zhu, 1962;Li and Ni, 2004), and ripple height is proportional to sand grain size (Sharp, 1963). The wavelength of sand ripples increases with time according to a logarithm (Werner and Gillespie, 1993;Yizhaq et al, 2004) or power function (Valance and Rioual, 1999;Csahók et al, 2000;Andreotti et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…However, sand ripples disappear when wind velocity exceeds a critical value (Rasmussen et al, 2015). The propagation velocity of sand ripples is inversely proportional to sand height so that small ripples can catch up with and merge into larger ripples (Bagnold 1941;Sharp, 1963;Forrest and Haff, 1992;Landry and Werner, 1994;Hoyle and Woods, 1997). This is the primary effect of scale, as the volume increases with the cube of the length and the surface with the square of the length, and the wind is acting on the surface (Anderson, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…The propagation velocity of developing sand ripples decreases with time (Bagnold 1941;Sharp, 1963;Stone and Summers, 1972;Seppälä and Lindé, 1978), but has not been quantitatively validated. The propagation velocity of fully developed sand ripples increases as a power (Ling et al, 2003) or linear function (Sharp, 1963;Andreotti et al, 2006;Zhu, 2009) of wind velocity.…”

Section: Introductionmentioning

confidence: 99%

“…Continuously monitoring the topographic parameters of sand ripples is a good way to study ripple formation and evolution, but the application of this method is to a large extent restricted by existing techniques. This is also the reason why few comparisons have been made among numerical models, field observations (Bagnold, 1941;Sharp, 1963;Ellwood et al, 1975), and wind tunnel experiments on sand ripples (Seppälä and Lindé, 1978;Goossens, 1991;Werner and Gillespie, 1993;Andreotti et al, 2006). The drawback of simulation models results in obvious differences between simulation and experiment results.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study of aeolian sand ripples in a wind tunnel

Cao

Liu

et al. 2017

Earth Surf Processes Landf

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The topographic parameters and propagation velocity of aeolian sand ripples reflect complex erosion, transport, and deposition processes of sand on the land surface. In this study, three Nikon cameras located in the windward (0-1 m), middle (4.5-5.5 m), and downwind (9-10 m) zones of a 10 m long sand bed are used to continuously record changes in sand ripples. Based on the data extracted from these images, this study reaches the following conclusions. (1) The initial formation and full development times of sand ripples over a flatbed decrease with wind velocity. (2) The wavelengths of full development sand ripples are approximately twice the wavelengths of initially formed sand ripples. Both wavelengths increase linearly with friction velocity. During the developing stage of sand ripples, the wavelength increases linearly with time. (3) The propagation velocity of full development sand ripples is approximately 0.6 times that of the initially formed sand ripples. The propagation velocity of both initial and full development of sand ripples increase as power functions with respect to friction velocity. During the developing stage of sand ripples, the propagation velocity decreases with time following a power law. These results provide new information for understanding the formation and evolution of aeolian sand ripples and help improve numerical simulations.

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Section: Differences In Sand Ripples Along the Bed Surfacesupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Experimental study of aeolian sand ripples in a wind tunnel

Cao

Liu

et al. 2017

Earth Surf Processes Landf

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Mechanisms limiting the growth of aeolian megaripples

Katra

Yizhaq

Kok

2014

Geophysical Research Letters

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Megaripples are distinguished from regular ripples by their larger size and bimodal sediment distribution. The interplay between wind, grain size, and morphology controls their development, but the exact mechanisms that limit the size of megaripples have been unclear. Using wind tunnel experiments, we found two main mechanisms that limit the height of megaripples. The first mechanism is megaripple flattening due to strong enough winds that drive the coarse grains into saltation; the second mechanism is megaripple deflation by impacts of faster saltation grains. In this latter mechanism, the coarse grains are propelled by the impacts of fine saltating grains. The occurrence of both these mechanisms depends on the grain size distribution and increases with both megaripple height and wind speed. Thus, for a given wind environment and grain size distribution, there exists a limit on the size of megaripples, which is determined by these two mechanisms.

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MAHLI at the Rocknest sand shadow: Science and science‐enabling activities

et al. 2013

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During Martian solar days 57–100, the Mars Science Laboratory Curiosity rover acquired and processed a solid (sediment) sample and analyzed its mineralogy and geochemistry with the Chemistry and Mineralogy and Sample Analysis at Mars instruments. An aeolian deposit—herein referred to as the Rocknest sand shadow—was inferred to represent a global average soil composition and selected for study to facilitate integration of analytical results with observations from earlier missions. During first‐time activities, the Mars Hand Lens Imager (MAHLI) was used to support both science and engineering activities related to sample assessment, collection, and delivery. Here we report on MAHLI activities that directly supported sample analysis and provide MAHLI observations regarding the grain‐scale characteristics of the Rocknest sand shadow. MAHLI imaging confirms that the Rocknest sand shadow is one of a family of bimodal aeolian accumulations on Mars—similar to the coarse‐grained ripples interrogated by the Mars Exploration Rovers Spirit and Opportunity—in which a surface veneer of coarse‐grained sediment stabilizes predominantly fine‐grained sediment of the deposit interior. The similarity in grain size distribution of these geographically disparate deposits support the widespread occurrence of bimodal aeolian transport on Mars. We suggest that preservation of bimodal aeolian deposits may be characteristic of regions of active deflation, where winnowing of the fine‐sediment fraction results in a relatively low sediment load and a preferential increase in the coarse‐grained fraction of the sediment load. The compositional similarity of Martian aeolian deposits supports the potential for global redistribution of fine‐grained components, combined with potential local contributions.

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Wind Ripples

Cited by 327 publications

References 0 publications

Experimental study of aeolian sand ripples in a wind tunnel

Experimental study of aeolian sand ripples in a wind tunnel

Mechanisms limiting the growth of aeolian megaripples

MAHLI at the Rocknest sand shadow: Science and science‐enabling activities

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