毛乌素沙地南缘横向沙丘粒度分布及其对风向变化的响应  

Grain-size Variation on a Transverse Dune and Response to Wind Direction Changes on Southern Edge of Mu Us Desert

作　　者：哈斯[1] 庄燕美[1] 王蕾[2] 王志[1] 

机构地区：[1]北京师范大学资源学院,防沙治沙教育部工程研究中心,北京100875 [2]首都师范大学资源环境与旅游学院,北京100037

出　　处：《地理科学进展》2006年第6期42-51,共10页Progress in Geography

基　　金：国家自然科学基金(40471013)资助

摘　　要：在风季发生转换期间,根据不同方向风的持续时间,对毛乌素沙地南缘长48m,高8m的横向沙丘进行了7次断面形态测量和表面沉积物采样分析。结果表明,横向沙丘断面形态及表面沉积物粒度分布随区域气流方向和强度而发生变化。在沙丘各部位,丘顶及附近两侧的沙粒活动性强,表面沉积物粒径及分选参数变化显著。在粒径及分选参数中,粒径频率曲线、平均粒径和偏度对风的作用比较敏感,随时间的变化也明显,利用它们的变化可以解释区域气流变化对沙丘的影响。风向发生转换时期的短期观测和采样分析结果进一步说明采样时间是影响沙丘表面沉积物粒度特征的重要因素。The transect data of morphology and grain-size samples has been obtained from a transverse dune with 8m high and 48m long in the south edge of Mu Us Sandy Land in the period of wind direction transitions. The results show that there exist temporal changes in grain-size and its spatial pattern on transverse dune responding to different wind directions and magnitudes. These changes are more obvious in the creastal zone of dune with more sand activity. Great temporal changes take place in the grain size frequency distribution, mean grain size and skewness among the grain-size parameters. This suggests that these parameters are most suscep- tive to the wind, and so their changes can be used to explain the difference of dunes in the influence of different wind. The evidences of the wind direction, dune morphology and grain-size characteristics identified there not only have seasonal but daily changes in grain-size patterns on the dune when wind direction changes. It further confirms the conclusion that the time of sampling is as important as the site.

关 键 词：毛乌素沙地 横向沙丘 粒径及分选 风向 形态 

分 类 号：P931.3[天文地球—自然地理学]