戈壁砾石覆盖度与风蚀强度关系实验研究  

Gravel Cover of Gobi Desert and Its Significance for Wind Erosion: An experimental study

作　　者：王训明[1] 郎丽丽[1] 花婷[1] 张彩霞[1] 王振亭[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室,甘肃兰州730000

出　　处：《中国沙漠》2013年第2期313-319,共7页Journal of Desert Research

基　　金：国家自然科学基金项目(41071008和41225001)资助

摘　　要：戈壁表面的砾石覆盖度对风沙物质的运移有不可忽略的影响,在极端干旱区砾石覆盖是防沙治沙的重要手段。通过风洞实验模拟了阿拉善戈壁区砾石覆盖度与风蚀强度的关系。结果表明,当因地表风化作用等产生的松散颗粒物被吹蚀后,不同地点、不同样品之间风蚀强度有明显的差异,因而砾石覆盖度与风蚀强度之间的相关关系并不显著;但数据标准化后则表明,当砾石覆盖度在40%以下时,随砾石覆盖度的增加风蚀强度也有所增大。戈壁地区的风沙运动中,在砾石覆盖度小于40%条件下,不同风速下风蚀强度的变异系数是不同砾石覆盖度下的风蚀强度的变异系数的2倍左右。在极端干旱的戈壁区,影响风蚀强度的因素十分复杂,砾石覆盖度增大不仅不能控制风蚀现象的发生,反而增强气流对地表的风蚀能力,这一因素可能是阿拉善高原戈壁区成为中亚强沙尘暴主要源地的重要原因之一。Coverage of gravels plays a major role in sand transport and dust emission in extremely arid gobi deserts. Covering surfaces with gravels is often utilized as important sand-controlling technique. Using in- tact samples of gobi surfaces, we conducted wind tunnel experiments and related analyses to describe the gravel cover of the gobi desert and its significance for wind erosion. Results show that after loose particles on the gobi surfaces have been removed, due to differences of surface materials and their structures, there are high variations for sand transport in different sites and there are no significant correlations between gravel cover and intensity of wind erosion. However, after gravel cover and sand transport data have been normalized, the intensity of wind erosion increased with increasing gravel cover. When gravel cover was less than 40 %, the coefficient of variation of the sand transport resulted from wind velocity variations are a- bout two-folds of that under the gravel cover variations. Because in most gobi deserts the gravel cover is less than 40%, these results suggest that increasing gravel cover cannot restrain wind erosion. The low gravel cover in the A｜xa Gobi may be one of the important factors for it to become the potential dust source area in Central Asia.

关 键 词：风沙活动 戈壁 砾石 覆盖度 风蚀强度 

分 类 号：X169[环境科学与工程—环境科学]