塔克拉玛干沙漠大气降尘粒度特征——以塔里木沙漠公路沿线为例  

Study on Grain Size Characteristics of Dustfall in the Taklimakan Desert—A Case Study along the Tarim Desert Highway

作　　者：孙艳伟[1,2] 李生宇[1] 徐新文[1] 李莹[1,2] 范冬冬[1,2] 

机构地区：[1]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 [2]中国科学院研究生院,北京100049

出　　处：《干旱区研究》2010年第5期785-792,共8页Arid Zone Research

基　　金：中国科学院重要方向项目(kzcx3-sw-342);中国科学院西部行动计划项目(KZCX2-XB2-13);中国科学院"西部之光"人才培养计划项目(20052118);中国科学院新疆生态与地理研究所绿洲学者"博士人才"计划项目资助;国家自然科学基金项目(40701019);新疆维吾尔自治区重大科技专项(200733144-3)

摘　　要：选择塔里木沙漠公路沿线典型下垫面,通过连续野外定点观测、室内粒度分析等手段,研究塔克拉玛干沙漠腹地与复合纵向沙垄区不同地貌部位近地表大气降尘的粒度特征及其空间分异规律。结果发现:沙漠公路沿线大气降尘的平均粒径在3.28Φ～3.47Φ之间,以细砂、极细砂为主,粒径分布呈双峰态,表明降尘来源的多样性。沿线不同下垫面降尘中粒径<50μm的细粒物质组成差异明显,位于沙漠北部和中部开阔的垄间区是沙尘的潜在源地。复合纵向沙垄区不同地貌部位的降尘细粒物质组成(粒径<50μm)差异明显,垄间区降尘中的细粒物质含量最高。非尘暴降尘较之尘暴降尘偏细,粉砂和黏土含量更多,分选性更差。大气沉降颗粒的粒度分形维数可以从整体上反映出颗粒物的粒度分布和级配特征,是描述大气沉降颗粒物粒度特征的重要指标。Study on the laws of wind-blown sand movement and its relationships with the geomorphological settings and surface materials are one of the important fields of desert researches.In this study,the typical underlaying surface along the Tarim Desert Highway is selected as the study area.Grain size characteristics and spatial distribution of dustfall were studied by the means of continuous spot observation along the complex longitudinal dune chains in the hinterland of the Taklimakan Desert and the particle size analysis in laboratory.The results show that the average grain size of dustfall along the Tarim Desert Highway varies in a range from 3.28Φ to 3.47Φ.The dustfall is dominated by fine sand and very fine sand,and the grain size distribution curves are bimodal,which reveal that the sources of dustfall are various.On the larger scale,the difference of composition of fine material（ 50 μm） is obvious among different underlaying surfaces.The characteristics of underlaying surface and its composition are the determining factors of wind-blown sand-dust.On the small scale,the particle size of dustfall in the inter-dune areas in the complex longitudinal dune region is the finest compared with that in other regions.The fine material content in the inter-dune areas is the highest among all the geomorphological positions.So it is considered that the inter-dune areas in the northern and central parts of the desert are the potential sources of aeolian dust.Dust collected under non-dust weather is poorer in sorting,coarser and has higher silt and clay content than that collected under dust weather,and the curves of grain size distribution of both are bimodal.This result reveals that dustfall is the mixture from the local area and the remote regions.The correlation analysis between the fractal dimensions and the particle size parameters reveals that the fractal dimensions can be effectively indicators of the grain size distribution and composition characteristics of aeolian dust,and they are one of the important indices

关 键 词：大气降尘 粒度特征 分形维数 塔里木沙漠公路 塔克拉玛干沙漠 

分 类 号：X513[环境科学与工程—环境工程]