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沙漠化研究的现状与趋势 总被引：7，自引：0，他引：7
２０世纪是沙漠化概念形成与发展的主要时期，通过回顾国内外沙漠化研究的兴起与发展历程，阐述了其研究现状，介绍了对沙漠化的定义、成因、时空尺度、过程与指征等有关问题上的主要观点，分析了目前沙漠化研究中所存在的问题及其发展趋势，并提出了今后应研究的主要课题。 相似文献
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沙漠化:从圈层耦合到全球变化 总被引：3，自引：0，他引：3
从沙漠化概念提出伊始 ,沙漠化成因机理的研究就一直成为学术界关注的焦点。沙漠化过程究竟有多少是由自然因素所致 ,多少是由人类活动所为 ,诸因素与沙漠化之间有何内在关系 ,沙尘天气发生发展过程及其诱因等 ,当属地球系统科学应解决的难题。文章从全球变化的角度 ,将沙漠系统视作一种类生命的非线性动力系统 ,指出沙漠化源于地球表层系统各圈层之间复杂的相关与耦合作用 :气候变化是控制沙漠进退的首要因素 ;陆表水持续亏损则是导致干旱、半干旱地区沙漠化发展的直接原因 ;岩石圈构造运动塑造了不同的地形地貌单元 ,奠定了沙漠分布的地理格局 ;人类的不当活动和气候变化引起的生物生产力的衰退及土地覆盖的破坏 ,造成了现代沙漠化的快速扩张。 相似文献
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毛乌素沙地沉积物粒度特征与土地沙漠化 总被引：5，自引：0，他引：5
为了研究毛乌素沙地沉积物的粒度特征与土地沙漠化的地质成因类型,通过系统研究沙地及相邻地区晚更新世以来在沙地内部、覆沙黄土区、黄土高原和河流谷地与湖泊等不同地质构造地貌条件下所形成的沉积物粒度特征,指出不同地质成因类型的沉积物是这些地区土地沙漠化的物质基础,区分不同类型的沉积物也是构成不同地质成因类型土地沙漠化分类的理论基础,探讨了不同地质作用对土地沙漠化的贡献及其对土地沙漠化防治方面的意义。研究表明,研究区的土地沙漠化是以各种类型的就地起沙为主要特征,地表径流的水力搬运是沙漠化物质搬运的重要途径。现代毛乌素沙地及其邻区的土地沙漠化是对地质历史时期形成的各种沉积物的进一步搬运、分选和再沉积过程,具有相对复杂的粒度特征。 相似文献
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土地沙漠化的因素有自然因素和人为因素。自然因素有气象、地形地貌、地层、构造等;人文因素有滥牧、滥垦、滥樵等。本文以东胜煤田北部地区为研究对象,通过对自然因素中地质因素分析,以期探讨沙漠化的内在原因。１沙漠的分布与地质构造研究区位于华北地台内蒙古地轴的南?.. 相似文献
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要重视全球变化对我国北方沙区可能影响的研究 总被引：3，自引：1，他引：3
讨论了全球变化及其对我国北方沙区可能影响的三个问题。首先，全球变化是人为因素与自然变化的藕合，不能忽视全球自然变化过程的研究;其次，沙漠的变化主要与气候
干湿变化有关，要注重研究未来增暖伴随的降水变化，预浏土地沙漠化未来发展趁势;第三，要研究土地沙漠化及其逆转对气候的反馈作用。
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干湿变化有关，要注重研究未来增暖伴随的降水变化，预浏土地沙漠化未来发展趁势;第三，要研究土地沙漠化及其逆转对气候的反馈作用。
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神府－东胜矿区在特写的自然地质环境和人为因素的影响下，土地沙漠化呈不断扩展的演化趋势。矿区大规模的开发建设，更加速了沙漠化进展。本文利用典型地段的沙漠化发展速率，依据矿区总体设计模型，对矿区自然沙漠化趋势和开矿新增沙漠化土地面积进行了定量预测，并提出了相应的防治措施。 相似文献
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科学分析人为因素在沙漠化过程中的作用是沙漠化研究的关键问题之一。研究普遍认为,人为因素是当前沙漠化的主要原因,滥垦、滥牧、滥樵是其主导因素,其中尤以滥垦的作用为主。现以西藏中部雅鲁藏布江流域为研究区域,探讨人为因素在沙漠化过程中的作用。回土地沙漠化现状区内有沙漠化土地314．IX104m2,占区域面积13．l％,其中轻度、中度和重度沙漠化土地分别为133．9X104m2,164．4X104m2和15．8x104m2。区内沙漠化土地分布广泛且又相对集中,并造成了多方面危害,计有2．88X104m2耕地、331．28X10‘hln‘草地、462个村庄、292．3kin公路、186．0k 相似文献
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基于RS和GIS的沙漠-黄土过渡带土地沙漠化分布与变化研究--以陕北榆林地区为例 总被引：5，自引：0，他引：5
选择毛乌素沙漠和黄土高原过渡带——陕北榆林地区作为研究区域,在地理信息系统支持下,对两个不同时期的遥感影像进行了解译,总结了该区10余年来沙漠化土地景观特征,分析了土地沙漠化空间格局的动态变化规律。结果表明,研究区内沙漠化土地形势仍十分严峻,沙漠化土地面积占土地总面积的67．7％,其空间分布具有明显的不平衡性,表现为西北部和中部区域沙漠化程度较为严重,土地沙漠化空间分布的不平衡性与该区自然因素和土地利用方式的空间差异有关。经过几十年的积极治理与改造,该区土地沙漠化过程逐渐趋于稳定。通过探讨土地沙漠化的成因,认为自然环境与人类行为的相互作用及在时间尺度上的矛盾造成了该区持续的土地沙漠化过程。 相似文献
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Identifying the provenance of aeolian sediments in the Hunshandake Sandy Land is of great importance for understanding the formation of the dune fields in the mid-latitudes and for deciphering information about desert’s responses to global change. By determining the major and trace elements concentrations of aeolian sands in three grain size fractions from the central and western parts of the Hunshandake Sandy Land, we systematically study the provenance and the depositional history of aeolian sands in this desert environment. Our results show that aeolian sands from the Hunshandake Sandy Land are enriched in SiO2 and are depleted in many other elements compared to those of the Upper Continent Crust (UCC). Variations of the immobile elements ratios like Zr/Hf, La/Yb, Th/Nb, La/Nb,LaN/YbN , GdN/YbN are relatively large in the coarse and medium fractions but minor in the fine fractions. Eu anomalies are quite different in the coarse fractions, but mostly positive in the medium fractions and all negative in the fine fractions. Decreasing tendency of Zr concentrations from the west to the east in the Hunshandake Sandy Land is evident in the coarse sands but rather weak in the fine grain size fractions. Our geochemical data indicate that the sources for the coarse and medium fractions of aeolian sands are diverse, influenced by local geology and geomorphology, while the fine sand fractions are more homogenous due to intensive mixture mainly by aeolian processes. Various ratios of immobile elements suggest that these sands should be sourced primarily from the surrounding mountains by fluvial/alluvial processes rather than from any remote territories. Aeolian sands with Ce negative anomalies are widely distributed in the Hunshandake Sandy Land, indicating that aquatic environments have occurred extensively prior to the occurrence of the dune field. 相似文献
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本文在毛乌素沙地景观分类、制图及景观动态研究的基础上,分析了50年代以来毛乌素沙地荒漠化发展状况及其时空特征,并对其扩展原因进行了分析和探讨。结果表明,50年代以来,该地区荒漠化整体上处于迅速扩展之中,只是某些局部地方植被得到一定程度的恢复;荒漠化扩展存在明显的空间和时间差异：西北部纯牧区扩展速度远远高于东部和南部半农半牧地区,70年代末至90年代初扩展速度远远低于50年代末至70年代末;荒漠化的迅速扩展主要是由于不合理的人类活动造成的,气候波动也有一定影响。 相似文献
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中国北方东部沙质荒漠化的地学观 总被引：8，自引：2，他引：8
中国北方东部的土地荒漠化主要受新构造运动以来的权造－沉积特征、青藏高原隆升所引起的全球气候变化、尤其是亚洲季风等地质背景控制。北方东部沙质荒漠化区域地质分类，按其成因可分为就地起沙型、风沙型和土地粗粒化型等3种类型。其中，就地起沙型沙质荒漠化主要分布在东部毛乌素、科尔沁、浑善达克、呼伦贝尔等沙地内，流经这些沙地的古河道，广泛发育河湖相砂质沉积物以及以砂质沉积物为母质的土壤分布区。风沙型沙质荒漠化主要分布在上述沙地的边缘地带，如毛乌素沙地以南的覆沙黄土区等。土地粗化主要分布在内蒙古锡林郭勒草原－河北坝上草原－河北坝上草原，其土壤类型多为含砾沙土，其土壤母质为基岩风化壳、残坡积或冲洪积物。荒漠化发展趋势上，尽管就地起沙型沙质荒漠化在毛乌素、科尔沁和浑善达达沙地的局部地区均有所逆转，但总体上，在北方广大地区，主要以地表土壤粗化为主的荒漠化和风沙型荒漠化等均有不同程度的扩大。上述不同类型的沙质荒漠化，总体上受地背景控制。其中，第四纪以来的构造－沉积特征控制着不同类型荒漠化的区域分布，气候变化控制着荒漠化的进程，人类活动则是在上述背景的基础上进行。 相似文献
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Aeolian desertification from the mid-1970s to 2005 in Otindag Sandy Land, Northern China 总被引：1，自引：0，他引：1
Aeolian desertification in Otindag Sandy Land has expanded dramatically during the past 50 years. This research explored processes
and causes of aeolian desertification in the study area. The results showed that aeolian desertification development in Zhenglan
Qi of typical region located at the center in the study area can be divided into three stages including rapid occurrence before
1987, parts of rehabilitation and most of deterioration from 1987 to 2000 and little rapid rehabilitation occurrence from
2000 to 2005, according to remote sensing images and field investigations. Gradually declining MI indicated that climate change
was not the major cause of aeolian desertification development during the last 40 years, while increasing population should
be the underlying cause of local aeolian desertification. Irrational human activities mainly including unsuitable reclamation
in the 1960s and lasting over-grazing after 1980 are direct causes contributing to local aeolian desertification, especially
over-grazing, while climate change often played a revealer of irrational human activities mainly through drought events. Over-grazing
and undesirable climate have different functions during the whole aeolian desertification process. Over-grazing gradually
changed grasslands to slight aeolian desertified lands at the initial stage, while climate with windy days or droughts often
accelerated formation of serious aeolian desertified lands. Aeolian desertification in the study area both possesses occurrence
possibility and great rehabilitative potential. At present, more integrated countermeasures combating local aeolian desertification
still are expected. 相似文献
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Change trends for desertified lands in the Horqin Sandy Land at the beginning of the twenty-first century 总被引：2，自引：1，他引：1
Zhiwen Han Tao Wang Changzhen Yan Yubin Liu Lichao Liu Aimin Li Heqiang Du 《Environmental Earth Sciences》2010,59(8):1749-1757
The dynamics of desertification in the Horqin Sandy Land between 2000 and 2005 were analyzed using Landsat TM/ETM images and
the data-processing function of geographical information software. The results showed that the extent of desertified land
decreased at a rate of slightly more than 0.1 km2 year−1, from 22,423.1 km2 in 2000 to 22,422.4 km2 in 2005, indicating that desertification has been controlled in this area and that desert areas may be approaching a steady
state. The dynamics of desertification differed among land types. Desertification decreased most obviously in areas of previous
desert land. The area in which desertification was ameliorated was higher than the area that underwent further degradation,
but non-desertified land (113.3 km2) deteriorated at a rate of 22.7 km2 year−1 during this period. This significant change requires careful attention by managers in the study area. 相似文献
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Xiaoan Zuo Halin Zhao Xueyong Zhao Yirui Guo Jianying Yun Shaokun Wang Takafumi Miyasaka 《Environmental Geology》2009,58(6):1227-1237
The Horqin Sandy Land is one of the most severely desertified regions in northern China. Plant communities and soil conditions
at five stages of grassland desertification (potential, light, moderate, severe and very severe) were selected for the study
of vegetation pattern variation relating to soil degradation. The results showed that vegetation cover, species richness and
diversity, aboveground biomass (AGB), underground biomass, litter, soil organic carbon (C), total nitrogen (N), total phosphorus
(P), electrical conductivity, very fine sand (0.1–0.05 mm) content and silt (0.05–0.002 mm) content decreased with the desertification
development. Plant community succession presented that the palatable herbaceous plants gave place to the shrub species with
asexual reproduction and sand pioneer plants. The decline of vegetation cover and AGB was positively related to the loss of
soil organic C and total N with progressive desertification (P < 0.01). The multivariate statistical analysis showed that plant community distribution, species diversity and ecological
dominance had the close relationship with the gradient of soil nutrients in the processes of grassland desertification. These
results suggest that grassland desertification results in the variation of vegetation pattern which presents the different
composition and structure of plant community highly influenced by the soil properties. 相似文献
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甘肃省黑河流域土地沙漠化的水文学指征初探 总被引：1，自引：0，他引：1
黑河流域土地沙漠化及水资源合理利用一直是该流域研究的焦点问题。文章首先从土地沙漠化分布范围、种类、面积、沙漠化程度等方面，分析了黑河流域土地沙漠化的现状：土地沙漠化主要发生在流域的中下游地区，尤以额济纳绿洲沙漠化形势严峻；其次，从地表水、地下水之水质、水量方面分析了黑河流域水环境变化的状况：人类不合理的经济活动，导致黑河流域水资源环境恶化，具体表现在地下水、地表水水位下降、水质恶化。在此基础上，从黑河流域地表水及地下水着手，初步提出了黑河流域土地沙漠化的水文学指征体系：其中，地表水主要包括蒸发与蒸腾的消耗、径流和渗漏3个部分；径流部分又分为地表水流经区域及水量变化、干流水量的系列变化以及泥沙沉积3方面；地下水则主要有水质变化及水位的连续变化2方面。 相似文献
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Shulin Liu Tao Wang Jian Guo Jianjun Qu Peijun An 《Environmental Earth Sciences》2010,60(7):1459-1466
Dynamic change of vegetation in northern China from 1998–2007 was explored, based on SPOT-VGT data. The results showed that
the NDVI can effectively monitor vegetation change, but also the mean multi-year NDVI maximum of 0.10 basically can be considered
as the threshold of vegetation cover in northern China, and those places with smaller than or equal to the threshold value
mainly were covered by deserts, Gobi and lakes, salinization lands, glaciers, snow patches and bare mountains, etc. The change
trends of vegetation where sub-region C and D were affected by east-Asia monsoon were similar with the characteristics of
first decreasing, later increasing and finally slowly decreasing; the difference lies in that sub-region C maintained a lower
vegetation state, and sub-region D reached a higher state. The vegetation change of sub-region A was anomalous with smaller
fluctuation. The change trend of vegetation of sub-region B was not only extremely unstable, but also the change extent was
huge. As far as the whole of northern China is concerned, vegetation has not demonstrated obvious improvement since these
ecological construction and protection projects, and the area of vegetation degradation still is much larger than that of
vegetation improvement from 1998 to 2007, but there was a bigger spatial difference. Field investigation and remote sensing
monitoring reveal that vegetation has obviously been improved in the agro-grazing mixing zone and to the south, as well as
many oases in the northwestern arid zone, while vegetation still has worsened in the steppes, especially the Ulanqab steppe,
Hunshandake Sandy Land, the region along the Sino–Mongolia border within Xilingol Meng, Hulunbeir Sandy Land and the northern
Tianshan mountain region in Xinjiang. Human activities only obviously showed success in local regions. The compelling challenges
of restoring the eco-environment are still immense, especially in the northern grazing zone of China. 相似文献