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Freely accessible inventory and spatial distribution of large-scale landslides in Xianyang City,Shaanxi Province,China

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Earthquake Research Advances 2023年第3期3卷 11-18页

作者： Jingyu Chen Lei Li Chong Xu Yuandong Huang Zhihua Luo Xiwei Xu Yuejun Lyu National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing100085China School of Engineering and Technology China University of Geosciences(Beijing)Beijing100083China Key Laboratory of Compound and Chained Natural Hazards Dynamics Ministry of Emergency Management of ChinaBeijing100085China School of Earth Sciences and Resources China University of Geosciences(Beijing)Beijing100083China

In this study, we used high-resolution optical satellite images on the Google Earth platform to map large-scale landslides in Xianyang City, Shaanxi Province, China. After mapping, a comprehensive and detailed large-scale landslide inventory that contains 2 924 large-scale landslides was obtained. We analyzed the spatial distribu-tion of landslides with seven influencing factors, including elevation, slope angle, aspect, curvature, lithology, distance to a river, and distance to the fault. Landslide Number, Landslide Area, Landslide Number Density(LND), and Landslide Area Percentage(LAP) were selected as indexes for the spatial distribution analysis. The results show that the number and area of landslides in the elevation range of 1 000–1 200 m is the highest. The highest number of landslides was observed in the slope angle of 25°–30°. North-facing slopes are prone to sliding. The area and number of landslides are the largest when the slope curvature ranges from-1.28 to 0. The LND and LAP reach their maxima when the slope curvature is less than-2.56. Areas covered by the Tertiary stratum with weakened fine-grained sandstone and siltstone show the highest LND and LAP values. Regarding distance to a river, the LAP peaks in the range of 300–600 m, whereas the LND peaks in an area larger than 2100 m. The values of LND and LNP rise as the distance from the faults increases, except for the locations 30 km away from active faults. This phenomenon is because active faults in this area pass through the plain areas, while landslides mostly occur in mountainous areas. The cataloging of landslide development in Xianyang City provides a significant scientific foundation for future research on landslides. In addition, the spatial distribution results are useful for landslide hazard prevention decisions and provide valuable references in this area.

关键词： Xianyang City Loess Plateau Google Earth GIS Landslide spatial distribution

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Estimation of the Threshold Friction Velocities over Various Dust Storm Source Areas in Northwest China

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Acta meteorologica Sinica 2010年第5期24卷 548-557页

作者：朱好张宏升 Department of Atmospheric and Oceanic Sciences School of PhysicsPeking University

The emission of dust particles into the atmosphere is governed by the aerodynamic and resistant factors, which are quantified by the friction velocity u. and the threshold friction velocity u＊t, respectively. The threshold friction velocity u＊t influences the vertical dust flux and dust transport. Based on the micro-meteorological data obtained in the springs of 2004 and 2006 over Hunshandake desert area, Loess Plateau, and Gobi desert area, the relationship between dust concentration and friction velocity for the dust events that occurred over Hunshandake desert area was investigated, and the threshold friction velocities over the three different dust source areas were estimated. The results show that the value of dust concentration is low during the pre-emission stage of a dust storm event, and the rapid increase of friction velocity provides favor-able dynamic conditions for dust emission. During the dust emission stage, the dust concentration increases sharply due to mechanical and thermal turbulent mixing. At the calm-down stage, the dust concentration drops nearly linearly with the decreasing friction velocity, on account of the gravitational deposition of larger dust particles. When the dust concentration is higher than 200 μgm-3, it is considered as a dust emission process. According to the criteria, the values of threshold friction velocity over Hunshandake desert area and Gobi region are 0.6 and 0.45 m s-1, respectively. The threshold friction velocity over Loess Plateau depends on the wind direction, due to the complex terrain and inhomogeneous surface. The northwest wind shows the effects of the Mu Us desert in the northwest. The corresponding u＊t is 0.35 m s-1. The south wind exhibits the characteristics of the loess hilly dunes in the south, and the u＊t is 0.7 m s-1. The large roughness length of the loess hilly dunes and the large inter-particle cohesion for the clay soil texture increases the local friction velocity. Different threshold friction velocities and occurrence frequencies of strong wind

关键词： dust storm dust rising threshold friction velocity Hunshandake desert area Loess Plateau Gobi desert area

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Seasonal variations in the influence of vegetation cover on soil water on the loess hillslope

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Journal of Mountain Science 2020年第9期17卷 2148-2160页

作者： SHEN Ming-shuang ZHANG Jian-jun ZHANG Shou-hong ZHANG Hai-bo SUN Ruo-xiu ZHANG Yi-zhou School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China National Station for Forest Ecosystem Research in Ji County Ji County 042200Shanxi ProvinceChina

Soil water is the key factor that restricts the restoration of the local ecological systems in the Loess Plateau of China.Studying the effects of vegetation types on soil water and its seasonal variation helps to understand hydrological characteristics and provides insights into the sustainable restoration of vegetation.Therefore,the Caijiachuan watershed was chosen as the research object to investigate the water status of a 0-10 m soil layer under different vegetation types including Pinus tabulaeformis,Robinia pseudoacacia,Platycladus orientalis,apple orchard,natural forestland,farmland and grassland.By comparing the difference between soil water of different land use types and that of grassland during the same period,the seasonal changes of soil water status of different types were judged.The results show that(1)in the 0-10 m soil layer,the largest value of soil water content was in the0.3-0.4 m layer,and the lowest was in the 5.6-5.8 m layer.The depths at which the vegetation cover influenced the soil water were up to 10 m;(2)among summer,fall and spring,the soil water storage wasthe highest in the fall.In addition,the lowest value of relative accumulation was in the fall,which was the period in which the soil water recovered;(3)the soil water in the 0-10 m layer was in a relatively deficient state in the artificial forestlands,apple orchards and native forestlands,while the relative accumulation was in the farmland.In addition,the relative deep soil layers(8-10 m)had more serious deficits in the areas in which P.tabulaeformis,R.pseudoacacia and the apple orchard grew;(4)during the study period,the farmland in the summer had the largest relative accumulation(182.71 mm),and the land under R.pseudoacacia in the fall had the lowest relative deficit(512.20 mm).In the Loess Plateau,vegetation cover will affect the change of deep soil moisture and artificial forest will cause soil water loss in different degrees.

关键词： Seasonal variation Soil water Vegetation cover Hillslope Loess Plateau

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The application and comparison of several flux profile relations in CoLM

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Research in Cold and Arid Regions 2014年第1期6卷 73-80页

作者： ZhenChao Li ZhiGang Weia ZhiYuan Zheng Hong Wei Hui Liu Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences College of Global Change and Earth System Science Beijing Normal University

This paper discusses the important role that flux profile relations play in momentum flux, sensible heat flux, and latent heat flux simulations in CoLM （Common Land Model） and compares the application of three flux profile relation schemes in CoLM by means of the Loess Plateau Land-Atmosphere Interaction Pilot Experiment （LOPEX） of 2005. It reveals that the results simulated by the model barely changed in the original flux profile schemes of the models a^er eliminating the very stable condition and the very unstable condition, and there were only tiny changes in numerical values. This indicates that the corrected terms added to fm（ξm）,fh（ξh） were very tiny and can be ignored under very stable and very unstable circumstances. According to a comparison of the three flux profile relations, the simulation results were basically coherent by using any CoLM： the correlation coefficient of the simulation value and the observed value was 0.89, and this bears on the coherence with the numerical procedures for the flux pro- file relations under unstable circumstances. The simulation results were improved considerably by utilizing the Lobocki flux pro- file schemes, which numerical procedures under unstable circumstances differed significantly fi＇om other three flux profile schemes; in this case the correlation coefficient of the value of simulation and the observed value became 0.95. In the next itera- tion of this study, it will be of great importance for the development of the land surface process model to continue experimenting with the application of some novel flux profile schemes in the land surface process models in typical regions.

关键词： CoLM Loess Plateau flux profile relations comparison

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Modeling of state of vegetation and soil erosion over large areas

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International Journal of Sediment Research 2008年第3期23卷 181-196页

作者： Zhao-Yin WANG1*, Guangqian WANG2, and Guohe HUANG31 Prof., State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China2 Prof., State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China3 Prof. and Canada Research Chair, Environmental Systems Engineering Program, Faculty of Engineering, University of Regina, Regina, Sask S4S 0A2, Canada Prof. State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China Prof. State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China Tel: 86-10-62781748 Fax: 86-10-62772463 Prof. and Canada Research Chair Environmental Systems Engineering Program Faculty of Engineering University of Regina Regina Sask S4S 0A2 Canada

A vegetation-erosion model was developed to assess the extent of soil erosion and development trend of vegetation in the context of existing and contemplated vegetation-based soil erosion controls under different climatic, topographical and soil conditions. The model recognizes four vegetation-mediated soil erosion states: (i) an expanding vegetation coverage coupled with reduced erosion (C), (ii) a deteriorating vegetation coverage coupled with increased erosion (A), (iii) two transitional states between A and C, one with increasing erosion and vegetation coverage (B) and the other with decreasing erosion and vegetation coverage (D). With the model, the vegetation-erosion state of any particular area can be quantitatively described, by way of a vegetation-erosion chart, for varying climate, soil and topographic conditions, as demonstrated for the Xishan region, the East River basin, the Wangjiagou and Anjiagou watersheds (Loess Plateau), and the Xiaojiang watersheds (hot and dry valleys in the upper Yangtze River basin) in China. This paper presents the principles and results of area-specific investigations that track the fractions of the areas covered by vegetation and experiencing soil erosion (with soil loss determined in t/km2yr). This is done within the context of local soil erosion control initiatives via re-vegetation efforts, or the lack thereof, over the course of 30 years. The effectiveness of reforestation and erosion-control measures vary under different climatic, topographical and soil conditions. The vegetation may be quickly restored in the hot and wet East River basin but is very difficult on the dry and cold Loess Plateau. In the hot and dry valleys the vegetation can be restored if erosion is controlled and intensive reforestations for small watersheds are performed.

关键词： Soil erosion Vegetation coverage Loess Plateau Vegetation-erosion chart Reforestation

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INITIATION AND DEVELOPMENT PROCESSES OF TUNNEL SYSTEMS IN THE HILLY loess REGION OF NORTHERN CHINA

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International Journal of Sediment Research 2006年第3期21卷 171-179页

作者： T. X. ZHU1 Dr., Department of Geography, University of Minnesota-Duluth, 10 University Dr., Duluth, MN 55812, U.S.A. Department of Geography University of Minnesota-Duluth MN 55812 United States

Tunnel systems in the hilly loess region of northern China are among the largest and most complicated in the world. Tunnel formation and development processes were investigated in the Yangdaogou catchment over the period of 1989 through 2002. Newly formed tunnels on the roads in the Wangjiagou watershed were also examined in detail during a single storm in 2002. Soil samples were taken from various locations of the tunnel systems in the Yangdaogou catchment for chemical and physical analyses. The controlling factors of tunnel formation are surface drainage conditions and soil materials. Rapid downward mechanical erosion by storm flows seems to be responsible for the original formation of inlets. All tunnels are found in loess and none was found in red Tertiary earth. Underground tunnel paths often develop right above an impeding layer, mainly resulting from mechanical erosion rather than chemical dissolution. New inlets develop in old tunnel systems in two major ways. One is roof collapses of an existing tunnel path and the other is the mechanical scouring action of storm flows. A tunnel system can expand upslope or downslope but the associated processes differ. Upslope expansion often starts with the formation of one or more inlets resulting from surface washes, followed by the development of an underground tunnel path. Downslope development of a tunnel system is characterized by uneven enlargement of tunnel paths. This study suggests that the key to control of tunnel development is reducing surface water entering a tunnel.

关键词： Piping Tunnel erosion Semi-arid areas Gully erosion Loess Plateau

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生态系统服务权衡与集成方法

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生态环境与保护 2016年第5期 1-9页

作者：傅伯杰于丹丹

生态系统服务是人类从生态系统中所获得的各种惠益，自20世纪90年代提出后在国际上迅速成为生态学、地理学和环境科学等领域的研究前沿热点。联合国大会于2012年正式批准生物多样性与生态系统服务政府间科学政策平台(IPBES)建设，制定... 详细信息

生态系统服务是人类从生态系统中所获得的各种惠益，自20世纪90年代提出后在国际上迅速成为生态学、地理学和环境科学等领域的研究前沿热点。联合国大会于2012年正式批准生物多样性与生态系统服务政府间科学政策平台(IPBES)建设，制定概念框架，确定近期研究主要任务包括三项快速的评估和两项政策决策性的评估。本文探索了生态系统服务权衡及区域集成方法，并以黄土高原地区为例进行了应用。研究结果表明，土地利用变化与土壤保持、碳固定具有正效应，与产水量间存在负效应；粮食生产能力与农业生产条件改善、人工投入增加和技术进步密切相关。生态系统服务之间的消长和权衡具有尺度依赖性，植被恢复的区域适宜性评价及水分效应方面还需要进一步研究。

关键词：生态系统服务黄土高原权衡区域集成 ecosystem services Loess Plateau trade-off regional ensemble

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SEDIMENT YIELD MODELING FOR SINGLE STORM EVENTS BASED ON HEAVY-DISCHARGE STAGE CHARACTERIZED BY STABLE SEDIMENT CONCENTRATION

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International Journal of Sediment Research 2007年第3期22卷 208-217页

作者： Mingguo ZHENG1, Qiangguo CAI2, and Qinjuan CHENG3 1Assistant professor, Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences & Natural Resources Research, CAS, Beijing 100101,China. 2 Professor, Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences & Natural Resources Research, CAS, Beijing 100101,China. 3 Doctoral candidate, Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences & Natural Resources Research, CAS, Beijing 100101,China. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China. Chinese Acad Sci Inst Geog Sci & Nat Resources Res Key Lab Water Cycle & Related Land Surface Proc Beijing 100101 Peoples R China

The relation between runoff volume and sediment yield for individual events in a given watershed receives little attention compared to the relation between water discharge and sediment yield, though it may underlie the event-based sediment-yield model for large-size watershed. The data observed at 12 experimental subwatersheds in the Dalihe river watershed in hilly areas of Loess Plateau, North China, was selected to develop and validate the relation. The peak flow is often considered as an important factor affecting event sediment yield. However, in the study areas, sediment concentration remains relatively constant when water discharge exceeds a certain critical value, implying that the heavier flow is not accompanied with the higher sediment transport capacity. Hence, only the runoff volume factor was considered in the sediment-yield model. As both the total sediment and runoff discharge were largely produced during the heavy-discharge stage, and the sediment concentration was negligibly variable during this stage, a proportional function can be used to model the relation between event runoff volume and sediment yield for a given subwatershed. The applicability of this model at larger spatial scales was also discussed, and it was found that for the Yaoxinzhuang station at the Puhe River basin, which controls a drainage area of 2264km2, a directly proportional relation between event runoff volume and sediment yield may also exist.

关键词： Sediment yield Peak flow Flow-sediment relation Loess Plateau

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Rb and Sr Geochemical Characterization of the Chinese loess Stratigraphy and Its Implications for Palaeomonsoon Climate

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Acta Geologica Sinica(English Edition) 2000年第2期74卷 279-288页

作者： CHEN Jun WANG Yongjin CHEN Yang LIU Lianwen JI Junfeng LU Huayu Department of Earth Sciences Nanjing UniversityNanjing 210093 Department of Geography Nanjing Normal UniversityNanjing 210097 Department of Earth Sciences Nanjing UniversityNanjing 210093 Xi’an State Key Laboratory of loess and Quaternary Geology Chinese Academy of SciencesXi’an 710061

Concentrations and distributions of Rb and Sr in loess and palaeosol samples from the Luochuan profile have been studied, in grain-size fractions and chemical forms. Results show that Rb is quite rich in the fraction of less than 2 μm, and exits only in the residual phase, while Sr is distributed in sand and silt fractions, occurring in the residual and carbonate phases. Therefore, variations of the concentrations of Rb and Sr in loess and palaeosols are closely related not only to dustfall compositions depending on winter monsoon wind strength but also to summer monsoon-induced pedogenic intensity. This indicates that variations of Rb/Sr ratio in Chinese loess sequences represent cyclic alternations of East Asian summer and winter monsoon climates on the orbital time-scale. Variations in Sr concentrations along the sequence bear a high similarity to the oxygen isotope record of the deep sea sediments over the past 2.5 Ma, whereas variations in Rb concentrations are in good agreement with the record of magnetic susceptibility determined with the duplicated samples from the same profile. This suggests that (1) the high-latitude ice volume is responsible for East Asian monsoon variations and (2) the signal of magnetic susceptibility depends dominantly on pedogenesis in Chinese loess sequences.

关键词： Rb and Sr geochemical characterization Rb/Sr ratios loess sequence palaeomonsoon climate Loess Plateau

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欠发达地区污染企业的区位选择与空间正义

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生态环境与保护 2022年第9期

作者：马蓓蓓党星袁水妹薛东前宋永永

污染企业空间管治和优化是提高欠发达地区开发过程中抗风险能力的重要环节。基于空间正义视角，以内陆型欠发达地区黄土高原为例，依据理论指向和侧重点差异，构建了集维度、属性和空间于一体的“5+5+4”污染企业区位分析框架，探讨污... 详细信息

污染企业空间管治和优化是提高欠发达地区开发过程中抗风险能力的重要环节。基于空间正义视角，以内陆型欠发达地区黄土高原为例，依据理论指向和侧重点差异，构建了集维度、属性和空间于一体的“5+5+4”污染企业区位分析框架，探讨污染企业在欠发达地区内部形成的格局特征、区位规律及与空间正义的辩证关系。主要结论：①综合“城乡+边界+权力+经济+环境”5个维度研究结果的共同指向，当前黄土高原污染企业区位整体呈现出典型的区域开发初期“低水平均衡+能矿资源依赖”的空间特征。②城市网络发育相对成熟的城市群地区是污染企业的主要集聚区，但与发达地区类似的非均衡演化和去一级中心化趋势已初步显现。③在城乡空间和制度空间上，研究区未表现出明显的环境保护“城市中心主义”和“污染避难所”现象；在经济空间上，研究区整体处于EKC曲线的上升阶段，地方经济对污染企业存在至少不排斥的依赖关系；在环境空间上，空气质量与污染企业数量属于低水平的正向耦合，但未出现随污染企业集聚空气质量显著下降的演化特征。④相对发达的省会城市和区域副中心城市在污染企业布局中呈退出趋势，具有较好工业经济基础和能矿资源赋存的城市群二级节点城市应成为今后环境规制和产业准入等政策关注的重点地区。⑤欠发达地区开发过程中污染企业存续或承接的正义性判别是具有辩证性的复杂命题，地理学区域综合分析的学科优势能为该类研究提供科学支撑；本文立足中国区域发展实践构建了以空间正义为理论指向的污染企业区位分析框架，以期为后续研究提供空间视角下的测度工具。

关键词：污染企业区位选择空间正义欠发达地区黄土高原　　polluting enterprise location selection spatial justice underdeveloped areas Loess Plateau

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