Journal of Geographical Sciences ›› 2007, Vol. 17 ›› Issue (4): 453-468.doi: 10.1007/s11442-007-0453-7

• Climate and Environmental Change • Previous Articles     Next Articles

A wind tunnel simulation of the dynamic processes involved in sand dune formation on the western coast of Hainan Island

LI Sen1,2, LIU Xianwan3, LI Huichuan4, ZHENG Yinghua5, WEI Xinghu1   

  1. 1. Institute of Resources and Environment Science, Foshan University, Foshan 528000, Guangdong, China|
    2. College of Geography and Environment Science, Northwest Normal University, Lanzhou 730070, China|
    3. Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730070, China|
    4. Shunde Branch, Bureau of Land and Resources of Foshan City, Shunde 528300, Guangdong, China|
    5. College of Resources Science &|Technology, Beijing Normal University, Beijing 100875, China
  • Received:2007-03-21 Revised:2007-06-15 Online:2007-12-25 Published:2007-12-25
  • Supported by:

    National Natural Science Foundation of China, No.40671186; No.40271012

Abstract:

The western coast of Hainan Island exhibits a savanna landscape. Many types of sand dunes, including transverse dune ridges, longitudinal dune ridges, elliptical dunes, coppice dunes, and climbing dunes, are widely distributed in the coastal zone. In winter, high-frequency and high-energy NE winds (dominant winds) are prevalent, with a resultant drift direction (RDD) of S35.6°W. In spring, low-frequency and low-energy SW secondary winds prevail, with a RDD of N25.1°E. Wind tunnel simulations revealed that the airflow over the dune surface is the main factor controlling the erosion and deposition patterns of dune surfaces and the morphological development of dunes. In the region's bidirectional wind en-vironment, with two seasonally distinct energy levels, the airflow over the surface of elliptical dunes, barchan dunes, and transverse dune ridges will exhibit a transverse pattern, whereas the airflow over longitudinal dunes ridges exhibits a lateral pattern and that over climbing dunes exhibits a climbing-circumfluent pattern. These patterns represent different dynamic processes. The coastal dunes on the western coast of Hainan Island are influenced by factors such as onshore winds, sand sources, coastal slopes, rivers, and forest shelter belts. The source of the sand that supplements these dunes particularly influences the development pattern: when there is more sand, the pattern shows positive equilibrium deposition between dune ridges and dunes; otherwise, it shows negative equilibrium deposition. The presence or absence of forest shelter belts also influences deposition and dune development patterns and transformation of dune forms. Coastal dunes and inland desert dunes experience similar dynamic processes, but the former have more diversified shapes and more complex forma-tion mechanisms.

Key words: western coast of Hainan Island, coastal dune, surface airflow, dynamic processes, wind tunnel simu-lation