自然风成沙纹的形态特征及其与地表沙物理性状的关系

Shape characteristics of the natural aeolian sand ripples and their relations with the physical characteristics of surface sand.

为了进一步探明自然风成沙纹形态的形成、发育过程，该文通过野外观测和统计分析的方法，研究了自然风成沙纹的形态特征及其与地表沙物理性状的关系，并构建了沙纹形态特征与地表沙颗粒机械组成及容重之间的关系模型．结果表明，沙纹波长、迎风坡长、背风坡长和高度相互之间呈线性关系，与地表沙机械组成中粒径为3～1mm、1～0．25mm和0．005～0．00mm的颗粒组成之间呈多元线性函数关系，与地表沙容重之间呈三次函数关系；地表沙的平均粒径越大，其形成的沙纹越高，波长也越长；相反，平均粒径越小，其形成的沙纹越细小，波长也越短；在自然风成沙纹的形态塑造过程中，粒径为1-0．25mm的中粗沙扮演着重要角色．

In order to better understand the forming of natural aeolian sand ripples, this paper had researched the shape characteristics of them by field observation and investigation, and analyzed the relations between shape characteristics of sand ripples and physical characteristics of surface sand. The models between shape characteristics of sand ripples and bulk density or mechanic composition of surface sand were constructed. Results showed that there was linear relationship each other among sand ripple＇s four attributes--wavelength, windward slope length, leeward slope length and height. Those attributes assume multivariate linear models with sand grain sizes of 3-1 mm, 1-0.25 mm and 0.005-0.001 mm, and cubic functions with bulk density of surface sand. The bigger the average size of sand grain is, the higher and bigger the sand ripple is, and also the longer the wavelength is, or vice versa. Furthermore, the sand grain size of 1-0.25 mm in mechanic composition plays a major role in formatting and developing of natural aeolian sand ripples.