土壤学报2018，Vol.55Issue(1)：88-99,12.DOI:10.11766/trxb201706060235
新疆策勒绿洲—沙漠过渡带风沙运动沙尘物质粒径分形特征
Fractal Characteristics of Grain Size of Sand and Dust in Aeolian Sand Movement in Cele Oasis-Desert Ecotone in Xinjiang,China
摘要
Abstract
[Objective]Aeolian sand movement is very frequent in the Cele oasis-desert ecotone in Xinjiang of China. So it is of great importance to explore rules of the near-surface aeolian sand movements, in expectation of providing certain theoretical basis for prevention and control of sandstorms in the southern fringe of the Taklimakan Desert. [Method]In-lab measurements and assays,linear regression analysis and correlational statistical analysis were adopted to explore particle size and fractal characteristics of grain size of the sand and dust materials in sand movements on land surface and near surface over different terrains of the Cele oasis-desert ecotone. [Result]Results show that the sand and dust materials in various sand movements consist of five kinds of sand and dust materials,from very coarse silts to very fine sands,and coarse silts are the major component of the atmospheric dustfall,with fractal dimension varying in the range of 0.25~2.25 and the five kinds of aeolian sand and dust vary in mean fractal dimension of particle size, exhibiting an decreasing order of sand materials on the surfaces of nebkhas>thoseindustfall>those on bare flat sandy land> those transported near ground surface>those shifting with sandy,averaging 1.03~1.67 in fractal dimension of particle size,while standard deviations of their fractal dimension values are in an opposite trend. Along the prevailing wind direction from shifting sandy land to oasis,with growing vegetation coverage,fractal dimension of aeolian sand and dust materials increases,while wind speed declines. The very coarse silt and very fine sand particles in the air higher above the ground surface tend to get deposited around shrubs in the oasis-desert ecotone,so the fractal dimension of the sand and dust materials in nebkhas are the highest in value,while the surface wind speed on shifting sand dunes sparse in vegetation is high, more coarser sand particles get deposited on the surfaces of the shifting sand dunes,being the lowest in fractal dimension. Fractal dimension of the sand materials on the surfaces of nebkhasis linearly related to mean particle size,sorting coefficient and some others. But no such correlation is found with the sand materials on the surfaces of shifting sand dunes. Fractal dimension of the sand materials in nebkhas,shifting sand dunes and sand transported near ground surface is positively related to their clay content at the 0.01 significance level,but negatively related to their content of sand grade of material in nebkhas and sand transported near ground surface;positively related to content of silt grade materials in sand dunes on bare flat land and sand transported near ground surface;negatively related to silt content atthe 0.05 significance level in dustfall;but it has nothing to do with silt and sand contents on the surfaces of shifting sand dunes. [Conclusion]Particle size fractionation,movement mode,vegetation coverage,wind forces and terrain are the main causes responsible for the differentiation of characteristics of particle size and fractal dimension of the aeolian sand and dust materials in the oasis-desert ecotone.关键词
绿洲—沙漠过渡带/灌丛沙堆/流动沙丘/大气降尘/粒径分形/策勒Key words
Oasis-desert ecotone/Nebkhas/Shifting sand dune/Dustfall/Fractal dimension of particle size/Cele分类
农业科技引用本文复制引用
毛东雷,蔡富艳,方登先,雷加强,来风兵,薛杰,王雪梅..新疆策勒绿洲—沙漠过渡带风沙运动沙尘物质粒径分形特征[J].土壤学报,2018,55(1):88-99,12.基金项目
新疆维吾尔自治区高校科研计划项目(XJEDU2016I035)、新疆师范大学博士科研启动基金项目(XJNUBS1527)和国家自然科学基金项目(41601595,41661002,41561051)资助 Supported by the Scientific Research Projects for Higher Educational Universities in Xinjiang Uygur Autonomous Region(No. XJEDU2016I035)and Start-up Fund of Doctoral Research of Xinjiang Normal University(No. XJNUBS1527)and the National Natural Science Foundation of China(Nos. 41601595,41661002 and 41561051) （XJEDU2016I035）
