塔克拉玛干沙漠土壤粒度分布特征及其对粉尘释放的影响  

Characteristics of soil particle size distribution and its effect on dust emission in Taklimakan Desert

作　　者：杨兴华[1] 康永德 周成龙[1] 霍文[1] 杨帆[1] 潘红林 孟露 何清 Yang Xinghua;Kang Yongde;Zhou Chenglong;Huo Wen;Yang Fan;Pan Honglin;Meng Lu;He Qing(Institute of Desert Meteorology,China Meteorological Administration,Urumqi 830002,China;Xinjiang Meteorological Bureau,Urumqi 830002,China)

机构地区：[1]中国气象局乌鲁木齐沙漠气象研究所,乌鲁木齐830002 [2]新疆气象局,乌鲁木齐830002

出　　处：《农业工程学报》2020年第5期167-174,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：中国气象沙漠科学基金“地表土壤粒径谱对起沙通量模拟结果的影响”(sqj2018019),国家自然科学基金(41875019)资助。

摘　　要：塔克拉玛干沙漠是中国西北的重要粉尘源区,研究区域粒度分布特征及粉尘释放量有助于评估区域大气环境质量及其气候效应。基于此,按照空间分布特征及下垫面类型(农田、沙丘、荒漠)环塔克拉玛干沙漠采集地表土壤样品138个,利用Mastersizer2000激光粒度仪分析土壤粒度组成,利用DPM模型计算粉尘释放通量,以期揭示塔克拉玛干沙漠地表土壤微团粒粒度分布特征及其对粉尘释放通量的影响,研究结果表明:1)138个样品中流动沙丘和沙垄的粉砂和黏粒含量累计之和最少,约占10%~18%左右,属于砂质土和砂壤质土。农田(绿洲、林带区)样品多为草甸土,粉砂和黏粒累计含量约占50%~80%,戈壁(荒漠区)样品中粉砂和黏粒的含量差异较大,砂质土和砂壤土的粉砂和黏粒的含量累计之和约占20%~30%。2)地表土壤微团粒中粒径较小的是细砂和粉细砂,可用3个对数正态分布群体表示,即:粉细砂群体、细砂群体、粗砂群体,中值粒径依次为90、225、500μm,标准偏差分别为1.02、1.53、1.08,各占比例约为30%、49%、21%。3)塔克拉玛干沙漠粉细砂和细砂的粉尘释放量最大,中砂粗砂次之,极粗砂最少,其最大差值的数量级为10^-2μg/(m^2·s)。研究结果可以较好地反映不同下垫面粉尘释放差异,对定量评估区域乃至全疆的粉尘释放量等具有重要意义。Transport of dust sand caused by wind erosion is a serious problem in many arid regions in the world, and it plays animportantrolein global biogeochemical cycle. The dust induced by transport of aeolian sand can affect atmospheric radiation balance, climate, environment, air quality and human health. It has hence attracted increased attention in various areas ranging fromgeomorphology and climatology to meteorology andecological-environmental science. In addition to its natural origin, dust could also be instigated by anthropogenesis activities due to desertification.However, the relative contribution of the two origins is still an issue remaining elusive. In addition, being able to accuratelyestimate the potential of a dust source is crucial to evaluating the influence of desertification andclimate change on dust flux. The Taklimakan desert(TD) is the second largest shifting sand desert in the world, with about 85% made up by shifting sand dunes.It is animportant source of the dusts seen in China. Understanding particle size distribution of the sand and dust emission is helpful to evaluate quality of the atmospheric environment and the consequence for climate at regional scale. We collected 138 samples from soil surface based on spatial distribution and types of thesurfaces including farmland, dune and desert. Particle sizesof each sample was analyzed using the Mastersizer 2000 laser particle size analyzer, and the associated dust release flux was calculated using the DPM model.The particle size distribution of the microaggregates in each sample was obtained to elucidate its potential influence on dust release flux. The results showed that: 1) The content of silt and clay in the 138 samples was least, accounting for 10% to 18% of the total particles inthe mobile sand dunes, and 20% to 30% of the total particles in the sand ridges(e.g., sandy soil and sandy-sandy loams). Most samples taken from farmland(e. g., oasis and forest belt) are meadow soil, with silt and clay content being 50%-80%, differing from the sil

关 键 词：粉尘 粒度 侵蚀 土壤 释放 

分 类 号：X169[环境科学与工程—环境科学]