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1.
Modern dust storms in China: an overview 总被引：4，自引：0，他引：4
This paper discusses the sources, spatial distribution, frequency and trend of dust storms in China. Most dust storms in China originate from one of three geographic areas: the Hexi (River West) Corridor and western Inner Mongolia Plateau, the Taklimakan Desert, and the central Inner Mongolia Plateau. Dust is most likely from deteriorated grasslands, Gobi, alluvial, lacustrine sediments and wadis at the outer edge of deserts. But deserts themselves contribute only slightly to the dust storm directly. Two geographic areas frequently have dust storms: one is in the western Tarim Basin, a ground surface of deteriorated land and wadi, but it only affects its neighboring areas, and the other one is in the western Inner Mongolia Plateau, a ground surface of Gobi, alluvial and lacustrine sediments, but it causes most of the dust storms in north China. Generally speaking, dust storms have reduced in most regions of China from the 1950 to 2000. Dust storms are highly correlated with human activities and climate changes. 相似文献
2.
东亚沙尘源地、沙尘输送路径的遥感研究 总被引：27，自引：6，他引：27
东亚沙尘灾害严重影响东亚各国的生态环境 ,在源地大量侵蚀表层土壤 ,在输送过程中严重污染大气环境质量。此外 ,作为气溶胶 ,对区域辐射平衡和天气系统产生重大影响。本文利用 Sea Wi FS遥感数据分析了东亚沙尘灾害的源地、沙尘输送路径 ,结果显示 :东亚沙尘的三个主要源地是蒙古的戈壁、内蒙古中西部的沙漠戈壁和塔克拉玛干沙漠。沙尘输送路径有北路、中路和南路三条 ,北路主要影响中国的东北地区 ,中路主要影响中国的华北地区 ,南路主要影响中国的华中、华东地区。通过遥感确定沙尘源地和沙尘输送路径对于东亚沙尘灾害的治理有指导意义 ,也是对沙尘大气模式的一种检验。 相似文献
3.
Using intact samples of Gobi surfaces, we conducted wind tunnel experiments and related analyses to describe the surface characteristics of Gobi deserts and their significance for dust emissions in the Ala Shan Plateau, an area of Central Asia with high dust emissions. Under relatively high wind velocities (22 m s−1), the total sediment transport approached 700 g m−2, with the fine fractions (<50 μm in diameter) accounting for up to 26 g m−2. In consecutive experiments, the emission rates decreased greatly due to depletion of erodible particles. In the Ala Shan Plateau, coverage by gravels varied, and aeolian sediment transport increased with increasing gravel cover (to about 30%); above that level, transport decreased. Because gravel cover was less than 30% in most areas, the gravel may not play important role in dust emissions in this region. Although the Gobi surfaces are covered by gravel, high clay contents that may restrain sediment transport. In the Ala Shan Plateau, dust emissions therefore appear to be controlled mainly by the availability of fine particles, which is in turn controlled by their deposition by ephemeral streams, by their creation via physical, salt, and chemical weathering, and by other processes such as aeolian abrasion. 相似文献
4.
The degree to which dust emissions are controlled by geomorphic conditions, wind environments and land use was investigated using the dust storm frequency (DSF) and data from more than 300 meteorological stations throughout northern China. Our analysis showed that most dust emissions originated in gobi deserts that developed in piedmont alluvial fans of the Kunlun, Qilian and Helan mountains. Dust emissions are low from other gobi desert regions, such as the northern Gurbantunggut and eastern Taklimakan, where high vegetation coverage restrained dust emissions or where dust-size particles are not abundant after a long period of strong wind erosion. Sandy deserts with relatively high vegetation coverage or an extensive cover by mobile sands are not a major dust source. Although the highest dust emissions did not appear in regions with the highest wind energy, DSF trends in each region from 1960 to 2003 were closely related to local wind activity. DSF was low in regions with high levels of human activity, where the mean DSF from 1960 to 2003 did not exceed 4 days/year; even from the 1960s to the early 1970s, the period with the greatest DSF, frequency did not exceed 8 days/year, which indicates that extensive land use did not contribute to DSF. The low DSF in these areas might result from the fact that although land use could produce abundant fine soil fractions, vegetation coverage and soil moisture remained higher than in the gobi deserts of arid China, thereby decreasing dust-storm occurrence. 相似文献
5.
沙尘天气是东亚地区常见的灾害性天气之一,强沙尘天气的发生不仅导致建筑物倒塌、人畜伤亡、植被破坏,还会导致火灾、空气污染等环境问题,对人体健康、社会经济活动及其全球沙尘循环产生重要影响。然而从东亚地区沙尘天气在长时间序列区域特征角度上系统分析的研究较少。基于此,本文利用1981—2019年东亚地区697个地面气象站点沙尘数据,分析了其区域时空分布特征。结果表明：空间上,东亚沙尘天气集中在位于内陆干旱区的蒙古国和中国西北地区,其中弱沙尘天气集中在中国北方地区,而强沙尘天气则集中在蒙古国。月变化上,东亚沙尘天气集中在春季（3—5月份）,在相对低纬度的中国青藏高原北麓沙尘天气3月份最多,位于中纬度的中国北方大部分地区4月份最多,而较高纬度的哈萨克斯坦东部和蒙古国5月份最多。年际变化上,40a间东亚沙尘呈减少趋势,尤其是在2000年之后多项生态工程的有效实施下中国北方大部分区域沙尘天气显著减少,但近几年内蒙古中西部地区强沙尘天气呈增长趋势;在生态环境较脆弱的蒙古国和塔克拉玛干沙漠等区域弱沙尘天气和强沙尘天气均呈增长趋势。本研究对准确地掌握东亚沙尘分布特征和防范沙尘灾害具有重要意义。 相似文献
6.
基于CALIPSO星载激光雷达的中国沙尘气溶胶观测 总被引：2，自引：0，他引：2
基于2006年6月至2012年5月无云条件下CALIPSO星载激光雷达观测资料,分析中国典型地区（塔克拉玛干沙漠、柴达木盆地、戈壁区和华北）沙尘气溶胶分布。结果表明：塔克拉玛干沙漠和戈壁区为沙尘天气发生频率高值区,且前者在各高度层的沙尘发生频率都大于后者。沙尘发生呈季节性分布。塔克拉玛干沙漠在春季沙尘发生频率最大,抬升最高可至10 km,冬季频率最小,高度最低,主要分布在3 km以下。戈壁区在春季沙尘发生频率、抬升高度最大,冬季抬升高度最低,但低层发生频率大于夏、秋两季。在塔克拉玛干沙漠,沙尘光学厚度春季最大约为0.44,冬季最小约为0.17,春,冬季消光系数峰值最大,可达0.25 km-1,且随高度的递减率大于夏,秋季。在戈壁区和柴达木盆地,沙尘光学厚度春季最大、秋季最小。在华北,沙尘光学厚度春季最大、夏季最小,消光系数在2 km以上春季最大,这主要是由于春季远距离高空传输到华北的沙尘量最多。塔克拉玛干沙漠与柴达木盆地的退偏比为0.2~0.35,戈壁区为0.16~0.28,可能是由于塔克拉玛干沙漠的物质组成与柴达木盆地相同,而与戈壁区不同。华北因低层沙尘与其他气溶胶混合导致退偏振比廓线随高度递增。4个区域对流层上部退偏比全为0.2,表明高空气溶胶可能为来自相同源区的沙尘。 相似文献
7.
中国西北干旱区有大面积的戈壁地貌,但对其形成过程的研究不多。阿尔金山北缘的沉积物记录着临近戈壁地貌的发育过程。选择甘肃敦煌南湖绿洲附近的山水沟剖面作为研究对象,在独立的光释光测年基础上,通过对比分析粒度特征、磁化率和有机碳同位素值变化,探讨5 ka BP以来阿尔金山北缘戈壁沉积动力过程及其环境控制因素。结果表明：戈壁发育进程具有波动性,戈壁沉积动力在百（千）年时间尺度上受到环境因素制约,在2.67～3.57 ka BP和1.65～1.95 ka BP干热气候条件下,沉积物搬运动力较弱,戈壁发育受限;在4.27～4.84 ka BP时期水量较大,戈壁发育范围较广,属于扩张阶段。这一结果初步揭示了戈壁地貌演化与气候环境变化的联系。 相似文献
8.
《Geomorphology》2004,57(1-2):41-51
Dust samples, collected monthly for 15 years from 50 urban sites in 10 cities in Gansu Province, China, provide information on modern rates of dust deposition in the desert and Gobi areas and in the Loess Plateau. Dust deposition is highest during spring months and lowest during autumn months, in both the desert and Gobi areas and the Loess Plateau. There is a significant positive correlation between dust deposition and dust event, and an inverse correlation between dust deposition and precipitation. The 15-year mean maximums in the desert and Gobi areas and the Loess Plateau are 498.64 and 327.02 t km−2 year−1, respectively, and the mean minimums are 290.22 and 180.86 t km−2 year−1, respectively. Drought may have a widespread, major influence on the modern rates of the dust deposition. 相似文献
9.
戈壁沉积物组分结构具有分形特征,能否利用分形特征及其变异性指示戈壁地表沉积物形成过程中的风沙作用目前认识不足。通过计算内蒙古苏宏图戈壁地表表层沉积物的分形维数值并分析了其空间变异性。结果表明:沉积物分形维数值随0.050~0.179 mm跃移组分含量的增大而增大,随0.179~20.919 mm蠕移及风蚀残余组分含量的增大而减小。风为塑造戈壁地貌的主导因素,戈壁沉积物分形值小于冲积、洪积作用下的泥石流沉积物(2.630~2.738),大于风力作用为主的沙漠、黄土沉积物(2.122、1.930)。风力使戈壁形成“均质面”,空间变异程度为中等空间相关性(32.8%):主导上风向裸露戈壁地表,沉积物以蠕移及风蚀残余组分为主(平均含量59.88%),分形维数均值为2.39;下风向半荒漠戈壁地表,沉积物以跃移组分为主(平均含量46.96%),分形维数均值分别为2.45、2.48,受主导风影响较弱的山间砂砾质地表,蠕移及风蚀残余组分含量较多(平均含量58.22%),分形维数均值为2.46。分形及其变异性指标可反映戈壁沉积物组分变化中的风沙作用过程。 相似文献
10.
戈壁砾石覆盖度与风蚀强度关系实验研究 总被引：3，自引：1，他引：2
戈壁表面的砾石覆盖度对风沙物质的运移有不可忽略的影响,在极端干旱区砾石覆盖是防沙治沙的重要手段。通过风洞实验模拟了阿拉善戈壁区砾石覆盖度与风蚀强度的关系。结果表明,当因地表风化作用等产生的松散颗粒物被吹蚀后,不同地点、不同样品之间风蚀强度有明显的差异,因而砾石覆盖度与风蚀强度之间的相关关系并不显著;但数据标准化后则表明,当砾石覆盖度在40%以下时,随砾石覆盖度的增加风蚀强度也有所增大。戈壁地区的风沙运动中,在砾石覆盖度小于40%条件下,不同风速下风蚀强度的变异系数是不同砾石覆盖度下的风蚀强度的变异系数的2倍左右。在极端干旱的戈壁区,影响风蚀强度的因素十分复杂,砾石覆盖度增大不仅不能控制风蚀现象的发生,反而增强气流对地表的风蚀能力,这一因素可能是阿拉善高原戈壁区成为中亚强沙尘暴主要源地的重要原因之一。 相似文献
11.
Dust/sand storms are common events in the arid and semi-arid regions of Central Asia. The region is characterized by strong winds, scarcity of vegetation cover, continental climate with long and dry summers, frequent soil and atmospheric droughts. Central Asian drylands, covered by a great variety of desert types, represent a powerful source of mineral and salt aerosols.The main objectives of this study are to monitor and assess the spatial and temporal distribution of dust storms over the Central Asian region during the last seven decades. The identified active source areas of dust storms are located mainly in the sandy deserts and other types of deserts where the sensitive ecosystems suffered from human impact. The main persistent sources of dust storms are located in the large “dust belt” that extends from west to east over the southern deserts, north of Caspian Sea deserts, south of Balkhash Lake, and Aral Sea region. The results of the analysis show a significant decrease in dust/sand storm frequency during the last decades and considerable changes in the active source areas. 相似文献
12.
ZHU Bingqi YU Jingjie QIN Xiaoguang Patrick RIOUAL LIU Ziting XIONG Heigang 《地理学报(英文版)》2014,24(1):177-190
Sandy desert landscape is a geological product of arid climate and abundant sand materials supply in natural conditions, therefore the formation of sandy desert is an ideal studying object for understanding the interaction between various stratigraphic/epigenetic spheres of the earth system. However, until now, the knowledge about the provenance and formation of these deserts in Xinjiang, Central Asia is diverse and inconsistent, a systematic review is necessary. Ancient aeolian sand sediments in the internal areas of these deserts and their twin dust deposits in the Cenozoic strata surrounding the Xinjiang deserts are direct and indirect clues reflecting the provenance of sand materials and the formation and evolution of deserts. Based on the geochemical, mineralogical and isotopic evidences of desert sands and relevant deposits in the peripheral regions, this paper reviews the research progress on the development of the sandy deserts in Xinjiang, Northwest China. Many proofs proposed that desert sands in Xinjiang were mainly sourced from the ancient pluvial, alluvial and fluvial sediments and were eventually achieved because of the local sand supply. It pointed out that the settings of tectonic structure in Xinjiang had made sediments both in the Tarim Basin and the Junggar Basin being influenced greatly by regional hydrological system and aeolian processes originated from the planetary wind system of westerly, the East Asian winter monsoon and the topographical mountain-valley winds. However, the directions of transpor- tation paths are different between the hydrological dynamics and the aeolian dynamics, which are decided by the slantwise structures of the basins tectonics and the regional atmospheric circulation routes, respectively, and have determined anisotropies of the transport pathway of these sediments delivered by different agents. This results in a geological cycle of detrital sediment transportation in the two large sediment mixing, alternation and recycle basins and thus largely increases the degree of between younger and older sediment sources, as well as the complexity and diversity of sand provenances. 相似文献
13.
Ian Smalley 《Area》2008,40(1):131-134
A study of loess in Australia brings the idea of 'desert' loess back into view. Production of particles in deserts still presents problems, but deserts do make adequate storage regions for loess particles – usually produced in adjacent mountains. Straightforward for Central Asia or China (a particle source in High Asia and convenient deserts en route to eventual deposition), but the Sahara and Australian deserts traditionally present problems. If loess material is allowed to be silt-sized clay agglomerate particles as well as the usual clastic primary minerals, then loess in Australia seems reasonable. Loess acquires its remarkable loessic qualities via aeolian deposition – the nature of the particles is perhaps of lesser importance. A more generalised approach to airborne sediments might be attempted, with two major types of suspension material recognised: large dust (maybe coarse and very coarse silt, say 20–60 µm, or perhaps 4–6 phi) and small dust (fine and very fine silt, 2–8 µm, 7–9 phi). Loess is made from large dust. 相似文献
14.
根据1960-2010年全国701个地面站沙尘观测资料分析了中国春季沙尘天气的空间分布和年际变化,发现南疆和内蒙古两个沙尘源区的沙尘指数51年来都呈现出减小的趋势,其中内蒙古沙尘指数总体较小、年际变化较大,而南疆沙尘指数的波动较小。通过分析南疆和内蒙古沙尘指数典型高、低值年春季环流场发现,控制两个沙尘源区的环流场存在明显差异:南疆沙尘指数低值年时,西路入侵的冷空气减少,受此影响蒙古气旋和南疆热低压减弱,导致南疆地区近地面西风减弱,最终导致南疆沙尘天气减少;内蒙古沙尘指数低值年时,西北路和北路冷空气入侵次数减少,地面场上西伯利亚冷高压和蒙古高压减弱,并且蒙古气旋的发生发展受到限制,导致内蒙古西部近地面西北风和偏西风减小,最终导致内蒙古地区沙尘天气减少。 相似文献
15.
中国北方风尘沉积是晚新生代中纬西风和冬季风输送的粉尘相互加积的结果。对北方风尘沉积物来源和搬运动力的分析表明,风尘沉积的物质来源具有多样性,物源类型和分布、传输路径随时间变化。认为亚洲中部山地古风化壳可能是中国北方早期风尘沉积,尤其是第三纪红粘土的重要物源之一;晚新生代的粉尘源区类型由山地因干旱化被风蚀的红色风化壳逐渐向盆地周边被抬升的中、新生代砂泥岩过渡,再由盆地周边过渡到盆地内部的中生代与新生代的河湖沉积物和沙漠。同时大气环流格局的变化相应地导致了粉尘源区分布和传输路径的迁移。 相似文献
16.
17.
根据1960-2010年全国701个地面站沙尘天气观测资料分析了中国夏季沙尘天气的空间分布和年际变化,发现南疆和内蒙古两个沙尘源区的夏季沙尘指数51年来均呈现出减小的趋势。通过分析夏季沙尘指数典型高、低值年环流场发现：500 hPa高度场上强烈发展的高原-贝加尔湖平均脊和减弱的东亚大槽,减少了高空低值系统对南疆和内蒙古中西部地区的影响,地面场上“北负南正”的变压场分布使得两个地区西风和西北风减小,最终导致夏季南疆和内蒙古地区沙尘天气减少。沙尘指数高值年时影响两个地区天气系统的差异在于：影响南疆地区的天气系统主要是高空的西路冷空气和地面场上发展的南疆热低压,而影响内蒙古地区的则是北路和偏北路冷空气以及地面场上强烈发展的蒙古-内蒙古热低压。 相似文献
18.
Abstract:Sandy desert landscape is a geological product of arid climate and abundant sand materials supply in natural conditions,therefore the formation of sandy desert is an ideal studying object for understanding the interaction between various stratigraphic/epigenetic spheres of the earth system.However,until now,the knowledge about the provenance and formation of these deserts in Xinjiang,Central Asia is diverse and inconsistent,a systematic review is necessary.Ancient aeolian sand sediments in the internal areas of these deserts and their twin dust deposits in the Cenozoic strata surrounding the Xinjiang deserts are direct and indirect clues reflecting the provenance of sand materials and the formation and evolution of deserts.Based on the geochemical,mineralogical and isotopic evidences of desert sands and relevant deposits in the peripheral regions,this paper reviews the research progress on the development of the sandy deserts in Xinjiang,Northwest China.Many proofs proposed that desert sands in Xinjiang were mainly sourced from the ancient pluvial,alluvial and fluvial sediments and were eventually achieved because of the local sand supply.It pointed out that the settings of tectonic structure in Xinjiang had made sediments both in the Tarim Basin and the Junggar Basin being influenced greatly by regional hydrological system and aeolian processes originated from the planetary wind system of westerly,the East Asian winter monsoon and the topographical mountain-valley winds.However,the directions of transportation paths are different between the hydrological dynamics and the aeolian dynamics,which are decided by the slantwise structures of the basins tectonics and the regional atmospheric circulation routes,respectively,and have determined anisotropies of the transport pathway of these sediments delivered by different agents.This results in a geological cycle of detrital sediment transportation in the two large basins and thus largely increases the degree of sediment mixing,alternation and recycle between younger and older sediment sources,as wellas the complexity and diversity of sand provenances. 相似文献
19.
ZHU Bingqi YU Jingjie QIN Xiaoguang Patrick RIOUAL LIU Ziting XIONG Heigang 《地理学报》2014,24(1):177-190
Sandy desert landscape is a geological product of arid climate and abundant sand materials supply in natural conditions, therefore the formation of sandy desert is an ideal studying object for understanding the interaction between various stratigraphic/epigenetic spheres of the earth system. However, until now, the knowledge about the provenance and formation of these deserts in Xinjiang, Central Asia is diverse and inconsistent, a systematic review is necessary. Ancient aeolian sand sediments in the internal areas of these deserts and their twin dust deposits in the Cenozoic strata surrounding the Xinjiang deserts are direct and indirect clues reflecting the provenance of sand materials and the formation and evolution of deserts. Based on the geochemical, mineralogical and isotopic evidences of desert sands and relevant deposits in the peripheral regions, this paper reviews the research progress on the development of the sandy deserts in Xinjiang, Northwest China. Many proofs proposed that desert sands in Xinjiang were mainly sourced from the ancient pluvial, alluvial and fluvial sediments and were eventually achieved because of the local sand supply. It pointed out that the settings of tectonic structure in Xinjiang had made sediments both in the Tarim Basin and the Junggar Basin being influenced greatly by regional hydrological system and aeolian processes originated from the planetary wind system of westerly, the East Asian winter monsoon and the topographical mountain-valley winds. However, the directions of transportation paths are different between the hydrological dynamics and the aeolian dynamics, which are decided by the slantwise structures of the basins tectonics and the regional atmospheric circulation routes, respectively, and have determined anisotropies of the transport pathway of these sediments delivered by different agents. This results in a geological cycle of detrital sediment transportation in the two large basins and thus largely increases the degree of sediment mixing, alternation and recycle between younger and older sediment sources, as well as the complexity and diversity of sand provenances. 相似文献
20.
西北地区沙尘天气的时空特征及影响因素分析 总被引：13，自引：9，他引：4
利用1960—2005年西北地区135个台站的沙尘日数、月降水和气温资料,以及500 hPa高度场和太平洋海表温度资料,通过常规统计和诊断方法,分析了沙尘天气的时空特征及其影响因素。结果表明,除北疆北部外,西北地区大部分地方年平均沙尘日数在5 d以上,沙尘日数25 d以上的地方主要在南疆、青海西部、甘肃河西及中部地区以及宁夏、内蒙古中西部和陕北一带,而50 d以上沙尘高频区主要集中在塔克拉玛干沙漠周边地区以及巴丹吉林沙漠、腾格里沙漠和毛乌素沙地一带。沙尘天气在春季发生最频繁,而很少发生在秋季。近46 a年沙尘日数总体上呈显著下降趋势,在沙尘天气高发区的下降趋势更为明显。20世纪70年代中期开始,沙尘天气发生频数由较多期跃变为一个相对较少期。当北太平洋地区位势高度偏低,青藏高原至新疆500 hPa高压脊异常偏强,亚洲大陆中高纬高度场较常年偏高时,西北地区沙尘日数偏少,反之亦然。当春季太平洋海温表现为厄尔尼诺(拉尼娜)典型态时,同期沙尘日数偏少（多）。 相似文献