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101.
面向地貌学本源的数字地形分析研究进展与展望   总被引:5,自引:2,他引:3  
数字地形分析(DTA)是地理信息科学(GIS)研究的热点。但是,当前基于数字高程模型(DEM)的数字地形分析在地貌学研究中存在重形态轻机理、重现象轻过程、重地上轻地下等问题,急需从单一的地貌形态分析,迈向面向成因、过程与机理等地貌学本源问题的研究转变。据此,本文系统梳理了面向地貌学本源的数字地形分析的相关研究现状,并从地貌学本源认识、地貌形态建模、地形因子提取、以及其他地形分析方法等研究进行了系统的回顾、梳理与分析。研究表明,基于DEM的数字地形分析虽具有地貌特征分析的潜力与优势,但是,数字地形分析存在数据表达与分析模式上的先天缺陷,亟待通过基础理论与关键技术的突破,实现理论与方法的创新发展,实现从“坡面”走向“区域”,从“形态”走向“过程”,从“地形”走向“地貌”。而当今地球系统科学的研究发展态势也到了数字地形分析研究从重视地貌形态走向揭示地貌学本源的关键阶段。因此,本文从DEM数据模型增值、地形因子及其地形空间关系、以及宏观地形分析等侧面展望了面向地貌学本源的数字地形分析研究。当今基于DEM的数字地形分析研究,正像当前的GIS是否能够真正支撑地理学发展一样,已经处于一个非常关键的十字路口。面向地貌学本源的数字地形分析研究思路可望成为地理信息科学领域理论与方法创新的一次重要探索与实践。  相似文献   
102.
Geomorphology-oriented digital terrain analysis: Progress and perspectives   总被引:1,自引:1,他引:0  
Digital terrain analysis(DTA) is one of the most important contents in the research of geographical information science(GIS). However, on the basis of the digital elevation model(DEM), many problems exist in the current research of DTA in geomorphological studies. For instance, the current DTA research appears to be focused more on morphology, phenomenon, and modern surface rather than mechanism, process, and underlying terrain. The current DTA research needs to be urgently transformed from the study of landform morphology to one focusing on landform process and mechanism. On this basis, this study summarizes the current research status of geomorphology-oriented DTA and systematically reviews and analyzes the research about the knowledge of geomorphological ontology, terrain modeling, terrain derivative calculation, and terrain analytical methods. With the help of DEM data, DTA research has the advantage of carrying out geomorphological studies from the perspective of surface morphology. However, the study of DTA has inherent defects in terms of data expression and analytic patterns. Thus, breakthroughs in basic theories and key technologies are necessary. Moreover, scholars need to realize that DTA research must be transformed from phenomenon to mechanism, from morphology to process, and from terrain to landform. At present, the research development of earth science has reached the critical stage in which the DTA research should focus more on geomorphological ontology. Consequently, this study proposes several prospects of geomorphology-oriented DTA from the aspects of value-added DEM data model, terrain derivatives and their spatial relations, and macro-terrain analysis. The study of DTA based on DEM is at a critical period along with the issue on whether the current GIS technology can truly support the development of geography. The research idea of geomorphology-oriented DTA is expected to be an important exploration and practice in the field of GIS.  相似文献   
103.
Remotely sensed data show details of the geomorphic features and landscape evolution west of the Nile. The detected features include remnants of paleochannels, flutes and rock-mass movements. Fused radar/optical data, altitudinal profiles and 3D perspective view provided evidences of massive landslides that fully blocked the earlier Nile channel near to the Western Desert plateau. This channel was ~30 km west of the present Nile at ~100 m above the present level of the Nile. Subsequently, the fluvial activities shifted about ~10 km eastward, leaving behind several remnants of paleochannels, fluvial deposits, ancient landscape and Nilotic fauna. The automatic extraction of stream networks clearly depicts the developments of paleochannels. Our results revealed that fluvial activity switched from the Gallaba plain to the present Nile course through a series of tectonic and climatic changes. Furthermore, integration of radar and optical images provided an explanation for causes of the undulated forms ‘flutes’.  相似文献   
104.
试论地貌学的新进展和趋势   总被引:1,自引:0,他引:1  
地貌变化有内在的规律,对环境保育、资源利用和自然灾害防治有重要影响。作为交叉学科和地理学的重要分支学科,地貌学具有重要理论价值和实际意义。过去10多年来,随着遥感、地理信息技术和沉积物定年、地球物理和地球化学探测以及数值模拟等新技术和新方法的应用,地貌学家的研究视野和深度不断扩大与加深,在构造地貌、气候地貌和人类活动与地貌过程等传统领域有很多新进展,揭示了不同地貌单元的变化规律和机理,极大地推动了地貌学的发展。在新时代,除了继续加强传统地貌单元的深入研究外,地貌学的发展应与全球环境变化和未来地球等重大科学问题(计划)紧密结合;地貌学家要关心人类活动对地貌过程的影响及适应,并利用新技术开展地貌过程的定量重建和数值模拟。同时加强地理学专业学生的地质学基础学习、发展定量地貌学和行星地貌学、系统开展人类活动对地貌过程的影响和适应研究,是提升中国地貌学水平的途径,也可为推动国际地貌学发展做出贡献。  相似文献   
105.
柴达木盆地盐湖锂矿床成矿过程及分布规律   总被引:2,自引:1,他引:1  
柴达木盆地盐湖蕴藏230×10~4t锂,集中分布在别勒滩、东西台等4个盐湖,占我国卤水锂资源总量~80%,战略资源地位不言而喻。近年来提锂技术及工程化研究倍受重视,而对盐湖锂矿成因和分布规律的了解凸显不足,锂矿资源流失严重与之不无关联。研究查明,昆仑山高温热泉群含锂泉水长期注入洪—那河,流入终端盐湖,蒸发富集成矿;锂的年输入通量748.8 t,结合区内盐湖锂矿总储量保守估算,成矿期始于14 ka BP之后;洪—那河早期主要流向别勒滩,在山前冲积扇向北推进、扇前河改道北流后,方才形成含锂河水当前分配格局。据此,破解了别勒滩锂矿在研究区储量最大的原由。还查明了锂矿床仅存在于别勒滩,而在达布逊等3个区段不能成矿的原因。阐明了锂的来源与新生代火山喷发岩、深部岩浆房、昆仑大断裂活动有关,以及含锂热水持续远程输送至盐湖成矿的地貌和水文气候动因。企业应当根据锂的分布规律和矿床特征,迅速转变钾肥生产模式。  相似文献   
106.
国家自然科学基金项目资助的地貌学研究现状与效应   总被引:2,自引:2,他引:0  
程维明  刘樯漪  申元村 《地理学报》2016,71(7):1255-1261
通过对2010-2015年国家自然科学基金资助下地貌学研究项目的总体状况、项目类型、依托单位、研究区域、人才队伍、研究热点、成果产出、获奖及社会效应等方面的分析,归纳概括地貌学的研究现状与态势等。结果表明:近5年来,地貌学获得的资助项目呈上升趋势,相关研究不断深入,各类研究团队显著壮大;研究系统已由高等院校为主逐渐发展成高等院校与科研机构并行的格局;不同地域地貌学研究的发展程度、研究对象及热点问题均表现出一定的区域不均衡性;构造、河流水文、黄土、冰川、风沙等是目前中国地貌学研究的主体方向。从资助项目的研究成果和产生效应来看,地貌学研究得到恢复和较快速发展,发表论文的数量和质量稳步提升,资助项目成果获奖层次高、社会效益显著。  相似文献   
107.
Reconstructing the evolution of ice sheets is critical to our understanding of the global environmental system, but most detailed palaeo-glaciological reconstructions have hitherto focused on the very recent history of ice sheets. Here, we present a three-dimensional (3D) reconstruction of the changing nature of ice-sheet derived sedimentary architecture through the Quaternary Ice Age of almost 3 Ma. An extensive geophysical record documents a marine-terminating, calving Fennoscandian Ice Sheet (FIS) margin present periodically on the mid-Norwegian shelf since the beginning of the Quaternary. Spatial and temporal variability of the FIS is illustrated by the gradual development of fast-flowing ice streams and associated intensification of focused glacial erosion and sedimentation since that time. Buried subglacial landforms reveal a complex and dynamic ice sheet, with converging palaeo-ice streams and several flow-switching events that may reflect major changes in topography and basal thermal regime. Lack of major subglacial meltwater channels suggests a largely distributed drainage system beneath the marine-terminating part of the FIS. This palaeo-environmental examination of the FIS provides a useful framework for ice-sheet modelling and shows that fragmentary preservation of buried surfaces and variability of ice-sheet dynamics should be taken into account when reconstructing glacial history from spatially limited datasets.  相似文献   
108.
通过对祁连山东段童子坝河各级阶地的年代和变形程度进行测定,得到了河流阶地的形成年代和过程,推算出民乐—大马营逆断裂的活动强度和速率,并分析了阶地形成和气候变化之间的关系。童子坝河5级阶地(年龄分别为16.70±1.81 cal,ka BP、 10 092.5±27.5 cal a BP、8127.5±72.5 cal a BP、2900±60 cal a BP、282.5±17.5 cal a BP)均形成于气候由冷转暖的阶段,属于气候成因阶地。基于断裂两侧阶地面的平面几何形态并结合上、下盘阶地横剖面同级阶地的高差,得到T4、T3、T2和T1阶地在民乐—大马营断裂处的垂直位错分别为10.6±3.1,m、5.0±2.6 m、2.0±1.9 m和1.9±1.3 m,推算出全新世以来民乐—大马营断裂的垂直滑动速率为1.05±0.31 mm/a,水平缩短速率为1.02±0.60 mm/a。  相似文献   
109.
This paper uses detailed mapping of eskers to address three questions which are important for reconstructing meltwater behaviour beneath contemporary and ancient ice masses: ‘What controls the morphology of simple and complex esker systems?’, ‘How do esker systems evolve through time?’ and ‘Are esker patterns compatible with groundwater controlled hydraulic spacing of esker tunnels?’. Esker crestlines and widths are mapped on the Breiðamerkurjökull foreland for eight time slices between 1945 and 2007, from high resolution (~50 cm) aerial photography, permitting their long‐term morphological evolution to be analysed in a high level of detail. We find that complex eskers develop where meltwater and sediment is abundant, such that sediment clogs channels, forming distributary eskers. Isolated eskers are simpler and smaller and reflect less abundant meltwater and sediment, which is unable to clog channels. Eskers may take several decades to emerge from outwash deposits containing buried ice and can increase or decrease in size when ice surrounding and underlying them melts out. It has been suggested that groundwater–channel coupling dictates the spacing between eskers at Breiðamerkurjökull. Our results do not dispute this, but suggest that the routing of sediment and meltwater through medial moraines is an additional important control on esker location and spacing. These results may be used to better understand the processes surrounding esker formation in a variety of geographical settings, enabling a more detailed understanding of the operation of meltwater drainage systems in sub‐marginal zones beneath glaciers and ice sheets. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
110.
Glaciokarst is a landscape which combines karst features and hydrology as well as inherited glacial features. It is a result of glaciation upon a karst geomorphological system. The relationship between glaciers and karst is rather poorly known and inadequately recognized. This research focuses on three distinct karst areas along the Adriatic coast in the southern Dinaric Alps that were affected by the Quaternary glaciations. An insight into specific glaciokarst processes and surface features was provided through the study of the areas of the Lov?en, Orjen and Vele? Mountains. A glaciokarst geomorphology is in general well preserved due to the prevailing vertically oriented chemical denudation following de‐glaciation and almost the entire absence of other surface processes. Typical glacial erosional features are combined by a variety of depressions which are the result of a karstic drainage of sub‐glacial waters. The majority of glacial deposits occur as extensive lateral‐terminal moraine complexes, which are often dissected by smaller breach‐lobe moraines on the external side of the ridge. Those moraine complexes are likely to be a product of several glacial events, which is supported by complex depositional structures. According to the type of glacial depositional features, the glaciers in the study areas were likely to have characteristics of moraine‐dammed glaciers. Due to vertical drainage ice‐marginal fluvial processes were unable to evacuate sediment. Fluvial transport between glacial and pro‐glacial systems in karst areas is inefficient. Nevertheless, some sediment from the glacier margin is washed away by the pro‐glacial streams, filling the karst depressions and forming piedmont‐type poljes. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
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