| 柴达木盆地表土与大气降尘粒度Weibull组成及其环境意义 |
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| 引用本文： | 肖舜,周爱锋,黄小忠,金明,孙东怀,陈发虎.柴达木盆地表土与大气降尘粒度Weibull组成及其环境意义[J].中国沙漠,2012,32(5):1193-1200. |
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| 作者姓名： | 肖舜 周爱锋 黄小忠 金明 孙东怀 陈发虎 |
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| 作者单位： | 1. 兰州大学西部环境与气候变化研究院／西部环境教育部重点实验室,甘肃兰州730000／中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,陕西西安710075／陕西省气象局气候中心,陕西西安710014
2. 兰州大学西部环境与气候变化研究院／西部环境教育部重点实验室,甘肃兰州,730000 |
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| 基金项目： | 黄土与第四纪地质国家重点实验室开放基金项目，陕西省气象局博士基金项目 |
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| 摘 要： | 柴达木盆地北部现代地表不同沉积环境沉积物粒度分析结果显示,多数盆地地表沉积物质呈Weibull三峰分布,具有超细粒、细粒、粗粒3个组分,个别样品包含沙粒组分,绝大多数的样品匮乏细粒-超细粒组分,以高含量分选性较好的粗粒组分和低含量分选性差的细粒-超细粒组分为总体特征。现代沙尘暴天气降尘粒度分布模式较为单一,以高含量窄峰态的粗粒组分为显著特征。依据含量最高主峰所在Weibull粒度组分,本研究将全部粒度分布分为3种类型:以高含量细粒组分主导的F型、以高含量粗粒组分主导的C型和以高含量沙粒组分主导的S型。比较沙尘暴降尘、季节降尘和年降尘粒度分布模式的结果表明,研究区全年和季节大气降尘主要由沙尘暴天气降尘贡献,在细粒和超细粒组分上,同时混合有尘暴释放和正常天气条件下大气本底粉尘沉降两种来源的风尘成分。分析冬季研究区湖泊（苏干湖）冰层粉尘粒度分布模式发现,细粒组分含量显著偏高,可达70.6%,明显有别于其他沉积环境粒度组成,对比年降尘细粒-超细粒组分成因我们初步认为,细粒组分可用于指示冬季风盛行季节近地面大范围风场搬运风尘物质的状况。
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| 关 键 词： | 柴达木盆地 表土 大气降尘 粒度分布 Weibull组分 |
| 收稿时间： | 2012-02-16; |
Grain-size Weibull Composition of Surface Dust Deposits and Atmospheric Dustfall, and Their Environmental Implications in Qaidam Basin, China |
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| XIAO Shun,ZHOU Ai-feng,HUANG Xiao-zhong,JIN Ming,SUN Dong-huai,CHEN Fa-hu.Grain-size Weibull Composition of Surface Dust Deposits and Atmospheric Dustfall, and Their Environmental Implications in Qaidam Basin, China[J].Journal of Desert Research,2012,32(5):1193-1200. |
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| Authors: | XIAO Shun ZHOU Ai-feng HUANG Xiao-zhong JIN Ming SUN Dong-huai CHEN Fa-hu |
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| Institution: | 1(1.MOE Key Laboratory of Western China’s Environmental Systems/Research School of Arid Environment and Climate Change,Lanzhou 730000,China;2.State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710075,China;3.Climate Center of Shaanxi Meteorological Bureau,Xi’an 710014,China) |
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| Abstract: | Global warming has been proved by many observational data from all over the world.The role of aeolian dust in climate system has been especially paid much attention to due to its potential in cooling the Earth.Arid northwestern China is a main dust source region in the Northern Hemisphere.The fine grain and clay fraction particles in these areas can be uplifted into upper level air flow by westerly circulation and dispersed over a wide altitudinal range,and may deposit far from the source areas.Consequently,the fine and ultrafine components,equivalent to fine silt and clay fractions,have the global connections with aeolian dust,climate and ocean biogeochemistry.In comparison,the coarse grains are generally transported by surface wind in short-duration suspension episodes,and they accumulate in the adjacent downwind areas to form loess.In the paper,we summarize the grain-size distribution patterns of aeolian dust deposits from different sedimentary environments.Results show that there are lower content of fine and ultrafine components in surface deposits,higher content of coarse component in dust storm samples,and high content of fine component in dust-trapped lake ice column from the Sugan Lake in northern Qaidam Basin.There are similar grain-size distribution patterns in annual dustfall,seasonal dustfall and dustfall during duststorm events,which indicate that annual dustfall and seasonal dustfall are mainly contributed by regional duststorm events.In summer,the content of fine component in dustfall is slightly higher,which should be due to more precipitation.Detailed examination on the fine and the ultrafine components of annual dustfall,seasonal dustfall and duststorm samples suggests that dust particles originate not only from dustfall during duststorm events,but also from atmospheric dust loadings associated with westerly circulation.In addition,the fine component of dust trapped in lake ice column can be regarded a paleoclimatic proxy for winter wind regime responding to Siberian-Mongolian High Pressure System. |
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| Keywords: | Qaidam Basin surface dust deposits atmospheric dustfall grain-size distribution Weihull com ponents |
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