The airflow field and dynamic processes of pyramid dunes

• Published in: Journal of arid environments Vol. 45; no. 4; pp. 357 - 368
• Main Authors: Zhang, Weimin, Qu, Jianjun, Dong, Zhibao, Li, Xiaoze, Wang, Wanfu
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2000; Elsevier
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Geomorphology, landform evolution; local air circulation; pyramid dunes; sedimentary structures; Surficial geology; wind tunnel experiments; Asia; China; wind tunnel experiments; sedimentary structures; pyramid dunes; local air circulation; Pyramidal shape; Air flow; Geomorphology; Arid region; Dynamics; Wind tunnel test; Sedimentary structure; Dunes
• ISSN: 0140-1963; 1095-922X
• DOI: 10.1006/jare.2000.0643

Dune sedimentary structure and wind tunnel experimental results show that the pyramid dunes on the cliff top surface of Dunhuang Mogao Grottoes are formed under three wind directions (NE, SW and NW); the deformation and separation variety of chain dune. The local air circulation (SW) is key to the development of the pyramid dunes. Analysing the morphological dynamic processes indicates that inherent relations exist between trihedral pyramid dunes and other complex sand dune types (linear, reticulate and polyhedral pyramid dunes). The wind regime of multidirection, in conjunction with the connected main and subsidiary sand ridges, resulted in the geomorphological forms adapted to the near-surface air streams. It is concluded that integrated studies, including sedimentary structures and wind tunnel experiments, can make more efficient contributions to an overall, systematic and thorough understanding of the developmental processes of the pyramid dunes than previously used single-study methods.