海岸横向沙脊表面风沙流结构粒度响应的野外观测研究  

Field Measurements of Vertical Distribution of Different Sand Grain Sizes in Structure of Wind-sand Flow on Coastal Transverse Ridge

作　　者：董玉祥[1] Hesp P A Namikas S L 马骏[1] 

机构地区：[1]中山大学地理科学与规划学院,广东广州510275 [2]Depart ment of Geography and Anthropology,Louisiana State University,USA

出　　处：《中国沙漠》2008年第6期1022-1028,共7页Journal of Desert Research

基　　金：国家自然科学基金项目(40571019)资助

摘　　要：风沙流中沙粒粒度组成的垂向变化及不同粒径沙粒的垂向分布特征等是风沙流结构粒度响应的基本研究内容,但一直较缺少野外观测实证证据。在我国海岸沙丘集中分布的河北昌黎黄金海岸,选择规模高大、形态典型的横向沙脊,采用野外梯度风速仪和平口式积沙仪对其顶部风沙流结构的粒度响应进行了野外实地观测。结果表明,海岸沙丘表面风力的分选作用明显,与横向沙脊表面相比风沙流所含沙物质中细沙组分比例增多、粗沙组分比例降低;粒度构成的垂向变化是,在风沙流0—10 cm、10—40 cm和40—60 cm三个高程段内,分别是以中沙为主、中沙与细沙并重和以中沙为主,其中中沙含量在三个高程段内分别呈现出自地表向上逐渐降低、含量比较稳定、向上逐渐升高的垂向变化,细沙则呈现相应的反向变化,随之平均粒径也呈现为自下而上逐步变细、比较稳定到逐渐变粗的变化,但分选系数、偏度和峰态无明显差异;横向沙脊顶部的风沙流结构整体符合指数分布,但不同粒径沙粒的垂向分布特征并不相同,其中粗沙为幂函数分布,细沙遵循指数函数递减,中沙的指数函数和幂函数拟合均有较高相关系数,但在0—40 cm高度内更符合指数函数分布。The vertical change of sand grain size and vertical distribution characteristics of different sand grain size groups in the structure of wind-sand flow are important problems of research on the structure of wind-sand flow, but it is short of the field measurement data. On the typical coastal transverse ridge at Changli Gold Coast in Hebei Province, which is one of the most typical coastal Aeolian distribution regions in China and famous for the tall and typical coastal transverse ridges, this field work was carried out on the top of typical coastal transverse ridge in Changli coast by use of field vertical anemometer and sand trap. The field measurement results show： @Comparison of the composition of sand grain size in wind-sand flow with that on coastal transverse ridge fine sand proportion increases. and its top, the proportion of coarse @The proportion of middle sands at sands in wind-sand flow decreases and the heights of 0--10 cm on the top of transverse ridge decrease with the height, it steady keeps in 10--40 cm and increases with the height in 40--60 cm, but the proportion of fine sands has the reverse change with the height, which induces the mean size also has the same change feature, but other grain size parameters almost have no difference at different heights in wind-sand flow. @In the structure of wind-sand flow on the top of transverse ridge, the distribu- tion of the safid transport rate of coarse sands could be expressed by the power function, the distribution of the sand transport rate of fine sands can be expressed by an exponential function, the distribution of the sand transport rate of middle sands at 0--40 cm height also could be expressed by an exponential function, but it has almost the same high relation coefficient with the exponential function and the power function in the whole height.

关 键 词：海岸横向沙脊 风沙流结构 粒度 野外观测研究 

分 类 号：X169[环境科学与工程—环境科学]