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基于SQL Server Analysis Service(SSAS)的土地地类关系空间数据挖掘 被引量:1
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作者 任沂军 刘玲玲 +1 位作者 邹艳红 陈佳音 《城市勘测》 2014年第6期35-39,共5页
基于SQL Server Analysis Services(简称SSAS)提供的Microsoft关联规则挖掘算法和事务数据挖掘功能,通过利用Arc GIS软件、空间数据库引擎Arc SDE和数据库SQL Server软件,提出了一种新的土地地类关系挖掘实现方案。首先结合空间数据挖掘... 基于SQL Server Analysis Services(简称SSAS)提供的Microsoft关联规则挖掘算法和事务数据挖掘功能,通过利用Arc GIS软件、空间数据库引擎Arc SDE和数据库SQL Server软件,提出了一种新的土地地类关系挖掘实现方案。首先结合空间数据挖掘(Spatial Data Mining,SDM)相关技术方法,以土地利用数据库为基础,实现空间数据提取;然后通过空间关联操作将空间信息转化为事务,最后在SSAS中创建多维数据集,完成相关数据挖掘任务。基于某市实例土地利用数据库,采用该方法探测相邻地类间的隐含关系,通过建立相邻地类图斑空间关联规则挖掘模型,设置不同的参数,得到了一系列比较实用合理的关联规则,通过实践证明了这种方案的有效性。 展开更多
关键词 土地地类关系 SQL Server ANALYSIS Service(SSAS) 空间数据挖掘 关联规则算法
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露天煤矿开采对呼伦贝尔草原地类变化研究 被引量:3
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作者 刘雪冉 胡振琪 +1 位作者 许涛 朱琦 《中国矿业》 北大核心 2017年第5期69-73,共5页
基于2000年、2005年和2010年的三期Landsat4/5TM遥感影像,运用ArcGIS软件,制作2000年、2005年和2010年呼伦贝尔草原地类分布图,定量分析露天煤矿开采对整个呼伦贝尔草原的影响:(1)整个呼伦贝尔草原地类变化剧烈程度减缓,整体规模趋于平... 基于2000年、2005年和2010年的三期Landsat4/5TM遥感影像,运用ArcGIS软件,制作2000年、2005年和2010年呼伦贝尔草原地类分布图,定量分析露天煤矿开采对整个呼伦贝尔草原的影响:(1)整个呼伦贝尔草原地类变化剧烈程度减缓,整体规模趋于平衡,主要集中在草地转为建设用地和未利用土地,草地减少比重为0.38%;(2)露天煤炭开采加大草地减少面积,草地减少比重为3.09%,地类变化剧烈;(3)露天煤炭开采区耕地、林地、湿地、水域变化相对稳定,建设用地和未利用土地不断增加,主要来源于草地面积的减少。 展开更多
关键词 呼伦贝尔草原 露天煤矿 土地利用 土地地类
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Application of GIS in Ecological Land Type(ELT)mapping--A case in Changbai Mountain area 被引量:2
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作者 肖宝英 代力民 +1 位作者 陈高 邵国凡 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第1期56-60,84,共5页
This paper depicted the physiographic landscape features and natural vegetation situation of study area (the eastern Jilin Province), and expatiates the definition, basic characters and its development of Ecological L... This paper depicted the physiographic landscape features and natural vegetation situation of study area (the eastern Jilin Province), and expatiates the definition, basic characters and its development of Ecological Land Classification (ELC). Based on the combination of relief map, satellite photography for study area and vegetation inventory data of 480 sample sites, a 5-class and a 15-class ecological land type map was concluded according to 4 important factors including slope, aspect, vegetation and elevation. Ecological Classification System (ECS) is a method to identify, characterize, and map ecosystems. The Ecological Land Type (ELT) was examined and applied initially in eastern Jilin Province. 展开更多
关键词 Ecological Land Type(ELT) Ecological Classification System(ECS) Ecological land classification(ELC) Geographic Information system(GIS)
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Integrating TM and Ancillary Geographical Data with Classification Trees for Land Cover Classification of Marsh Area 被引量:14
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作者 NA Xiaodong ZHANG Shuqing +3 位作者 ZHANG Huaiqing LI Xiaofeng YU Huan LIU Chunyue 《Chinese Geographical Science》 SCIE CSCD 2009年第2期177-185,共9页
The main objective of this research is to determine the capacity of land cover classification combining spec- tral and textural features of Landsat TM imagery with ancillary geographical data in wetlands of the Sanjia... The main objective of this research is to determine the capacity of land cover classification combining spec- tral and textural features of Landsat TM imagery with ancillary geographical data in wetlands of the Sanjiang Plain, Heilongjiang Province, China. Semi-variograms and Z-test value were calculated to assess the separability of grey-level co-occurrence texture measures to maximize the difference between land cover types. The degree of spatial autocorrelation showed that window sizes of 3×3 pixels and 11×11 pixels were most appropriate for Landsat TM im- age texture calculations. The texture analysis showed that co-occurrence entropy, dissimilarity, and variance texture measures, derived from the Landsat TM spectrum bands and vegetation indices provided the most significant statistical differentiation between land cover types. Subsequently, a Classification and Regression Tree (CART) algorithm was applied to three different combinations of predictors: 1) TM imagery alone (TM-only); 2) TM imagery plus image texture (TM+TXT model); and 3) all predictors including TM imagery, image texture and additional ancillary GIS in- formation (TM+TXT+GIS model). Compared with traditional Maximum Likelihood Classification (MLC) supervised classification, three classification trees predictive models reduced the overall error rate significantly. Image texture measures and ancillary geographical variables depressed the speckle noise effectively and reduced classification error rate of marsh obviously. For classification trees model making use of all available predictors, omission error rate was 12.90% and commission error rate was 10.99% for marsh. The developed method is portable, relatively easy to im- plement and should be applicable in other settings and over larger extents. 展开更多
关键词 land cover classification classification trees Landsat TM ancillary geographical data MARSH
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Urban Spatial Restructuring in Transitional Economy——Changing Land Use Pattern in Shanghai 被引量:10
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作者 XU Jiangang LIAO Banggu +2 位作者 SHEN Qing ZHANG Feng MEI Anxin 《Chinese Geographical Science》 SCIE CSCD 2007年第1期19-27,共9页
For almost three decades, China has been undergoing significant transition from a planned economy to a market economy. Fast-paced economic growth and urbanization, interacting with market-oriented reforms in land re- ... For almost three decades, China has been undergoing significant transition from a planned economy to a market economy. Fast-paced economic growth and urbanization, interacting with market-oriented reforms in land re- sources allocation, have caused profound spatial restructuring of Chinese cities. This paper examines urban expansion and land use reconfiguration in Shanghai’s central city from 1979 to 2002, with a special focus on the effect of the adoption of the land-leasing system in 1988. The empirical research, which employs GIS-based spatial analysis tech- niques to explore land use data for multiple years, indicates fundamental changes in the spatial characteristics of urban development in Shanghai after this important land policy reform. 展开更多
关键词 land use pattern land policy GIS SHANGHAI China
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Land Use and Land Cover Change on Slope in Qiandongnan Prefecture of Southwest China 被引量:3
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作者 LU Liang GUO Luo ZHAO Song-ting 《Journal of Mountain Science》 SCIE CSCD 2014年第3期762-773,共12页
This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou provi... This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou province, China. The land use data were classified into five types, forest, farmland, grassland, water and built-up, the slope gradients were divided into four grades. Indices for analyzing land use features were defined by their proportions, transformation matrixes, land use degree and changes The results showed that all land use types can be found at every gradient. Generally, with the slope degree increased, the area of forest being augmented as well, while the area of the other land use types (farmland, grassland and build-up) declined. Moreover, a mass of farmland were shifted from other land use types from o° to 25°, while a quantity of forest were transformed from the other land use types on 〉 25° from 2993 to 2009. In terms of land use degree and changes, the area of farmland and buildup land use types decreased when slope degree increased. Finally, we calculated the five landscape pattern metrics: Patch Density (PD) value, Largest Patch Index (LPI), Shannon's Diversity Index (SHDI), Area-Weighted Mean Shape Index (AWMSI) and Contagion Index (CONTAG). The results of metricsanalysis showed that PD values, SHDI values and CONTA values had a similar variation trend, that is, they decreased when slope degree increased. There was no obvious variation trend on LPI value. 展开更多
关键词 Land use Land cover change Spatialgradient slope Landscape metrics Qiandongnanprefecture
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Effect of Agricultural Land Use Changes on Soil Nutrient Use Efficiency in an Agricultural Area,Beijing,China 被引量:5
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作者 CHEN Liding QI Xin +2 位作者 ZHANG Xinyu LI Qi ZHANG Yanyan 《Chinese Geographical Science》 SCIE CSCD 2011年第4期392-402,共11页
Agricultural land use and management practices may affect soil properties,which play a critical role in sustaining crop production.Since the late 1970s,several new agricultural land use types had been introduced in th... Agricultural land use and management practices may affect soil properties,which play a critical role in sustaining crop production.Since the late 1970s,several new agricultural land use types had been introduced in the rural areas of China.The purpose of this study is to evaluate the effect of these land use changes on the soil properties,nu-trient absorption rate,and nutrient use economic efficiency ratio in an agricultural area of Beijing.Specifically,the cropland,the orchard and the vegetable field were examined.Results of this study suggest that land use and farming management practices significantly affect the content of soil organic carbon (SOC),total nitrogen (TN),total phos-phorus (TP),and available phosphorus in the surface layer of 0-25 cm (p<0.05) in the Yanqing Basin,northwestern Beijing.Soil nutrients in each agricultural land use type decrease rapidly with the increasing soil depth.Orchard and vegetable field tend to have higher soil nutrients than the cropland does.However,the soil nutrient-absorption rate (NAR) of the orchard and vegetable field is lower than that of the cropland,even though orchard and vegetable field may provide much higher economic benefit.While increasing SOC,TN,and TP in the orchard and vegetable field by intensive farming may be a valuable option to improve soil quality,potential increase in the risk of nutrient loss,or agricultural non-point source pollution can be a tradeoff if the intensive practices are not managed appropriately. 展开更多
关键词 agricultural land use soil nutrient absorption rate (NAR) soil nutrient use economic efficiency ratio (NEER) soil property environmental effect
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The non-point output of different agriculture landuse types in Zhexi hydraulic region of Taihu Basin 被引量:2
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作者 LIHengpeng LIUXiaomei HUANGWenyu 《Journal of Geographical Sciences》 SCIE CSCD 2004年第2期151-158,共8页
This paper takes Zhexi hydraulic region in Taihu Basin as a study area. On the basis of hydraulic analysis function of Arcgis8.3, the drainages were delineated by selecting the monitoring points and discharge stations... This paper takes Zhexi hydraulic region in Taihu Basin as a study area. On the basis of hydraulic analysis function of Arcgis8.3, the drainages were delineated by selecting the monitoring points and discharge stations as outlets. The landuse map were finished by denoting the TM/ETM image. The precipitation map was finished by spatial interpolation according to the rainfall monitoring records. Overlaying the drainage boundary, landuse map and precipitation map, the rainfall, different landuse type area, and runoff pollution concentration and runoff were calculated. Based on these data in different sub-watersheds, by Origin7.0 regression tool, an equation is established to predict runoff using the relationships between runoff, precipitation depth and land use patterns in each of the sub-watersheds. Selecting the sub-watershed which is mainly composed of forest landuse type, the mean runoff concentration (MRC) from sub-watershed has been estimated. The mean runoff concentration of farmland has been estimated by the same methods after the contribution of forest landuse type was removed. The results are: for the forest landuse type, the mean runoff concentrations of COD, BOD, Total N and Total P are 2.95 mg/l, 1.080 mg/l, 0.715 mg/l, and 0.039 mg/l, respectively; for the farmland, the mean runoff concentrations of COD, BOD, Total N and Total P are 5.721 mg/l, 3.097 mg/l, 2.092 mg/l, and 0.166 mg/l, respectively. By using these results, the agriculture non-point pollution loads have been assessed. The loads of COD, BOD, Total N and Total P in Zhexi region are 14,631.69 t/a, 6401.93 t/a, 4281.753 t/a and 287.67 t/a, respectively. 展开更多
关键词 Taihu Basin Zhexi hydraulic region LANDUSE non-point pollution
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Surface Brightness Temperature Variation of Different Land Use Types
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作者 石亦霏 查勇 《Agricultural Science & Technology》 CAS 2011年第12期1873-1876,1971,共5页
[Objective] The aim of this study is to investigate the surface brightness temperature variation of different land use types.[Method] Based on MODIS data in 2008 and IGBP land classification system,the surface brightn... [Objective] The aim of this study is to investigate the surface brightness temperature variation of different land use types.[Method] Based on MODIS data in 2008 and IGBP land classification system,the surface brightness temperature in the Yangtze River Delta area was calculated,and its rules and reasons were also discussed in this study.[Result] Different land use types had its own special brightness temperature variation.During the day,the brightness temperature was as follows:grassland or urban and built-up landcropland,forest land and barrenwetland and water.During the night,the brightness temperature was as follows:water,wetland and barrengrassland or urban and built-up landforest land and cropland.Brightness temperature showed the trend of high in summer and low in winter or increasing in spring and decreasing in fall.The characteristics of surface thermal radiation could be reflected better by brightness temperature at night.Solar radiation,mixed pixel,heat capacity,water content were the main reasons for the difference of brightness temperature in different land types.[Conclusion] The brightness temperature variation of different land use types has significance for water content analysis in soil and dynamic monitoring of land use. 展开更多
关键词 MODIS Remote sensing Surface brightness temperature Land use type
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Monitoring urban land cover and vegetation change by multi-temporal remote sensing information 被引量:10
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作者 DU Peijun LI Xingli +2 位作者 CAO Wen LUO Yan ZHANG Huapeng 《Mining Science and Technology》 EI CAS 2010年第6期922-932,共11页
In order to analyze changes in human settlement in Xuzhou city during the past 20 years, changes in land cover and vegetation were investigated based on multi-temporal remote sensing Landsat TM images. We developed a ... In order to analyze changes in human settlement in Xuzhou city during the past 20 years, changes in land cover and vegetation were investigated based on multi-temporal remote sensing Landsat TM images. We developed a hierarchical classifier system that uses different feature inputs for specific classes and conducted a classification post-processing approach to improve its accuracy. From our statistical analysis of changes in urban land cover from 1987 to 2007, we conclude that built-up land areas have obviously increased, while farmland has seen in a continuous loss due to urban growth and human activities. A NDVI difference approach was used to extract information on changes in vegetation. A false change information elimination approach was developed based on prior knowledge and statistical analysis. The areas of vegetation cover have been in continuous decline over the past 20 years, although some measures have been adopted to protect and maintain urban vegetation. Given the stability of underground coal exploitation since 1990s, urban growth has become the major driving force in vegetation loss, which is different from the vegetation change driven by coal exploitation mainly before 1990. 展开更多
关键词 urban settlement land cover change VEGETATION hierarchical classifier system URBANIZATION NDVI NDVI difference urban remote sensing
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The dynamics of landscape-scale ecological connectivity based on least-cost model in Dongshan Island,China 被引量:2
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作者 WU Li-yun HE Dong-jin +3 位作者 YOU Wei-bin JI Zhi-rong TAN Yong ZHAO Li-li 《Journal of Mountain Science》 SCIE CSCD 2017年第2期336-345,共10页
As a hot topic in Landscape Ecology study,ecological connectivity is an important indicator for regional land sustainable use and biological protection. This paper conducted a systematic assessment of ecological conne... As a hot topic in Landscape Ecology study,ecological connectivity is an important indicator for regional land sustainable use and biological protection. This paper conducted a systematic assessment of ecological connectivity using remote sensing images of Dongshan Island in 1994, 2003 and2011. Based on least-cost modelling, the method takes into consideration the type of barrier, the distance impact, and the adjacent land use types to obtain the Barrier Effect Index(BEI) and Ecological Connectivity Index(ECI). The application of this method to Dongshan Island showed the ecological connectivity index(ECI) was low in 1994, improved in 2003, and decreased significantly in 2011. The results of the dynamic analysis of landscape structure showed farmland and roads were the main landscape classes that caused the low observed ECI in 1994 and 2003;these tended to divide the landscape and cause fragmentation. Construction land and roads were the main landscape classes resulting in low ECI in 2011,while forest and grassland had a high ECI. Trajectory analysis showed ECI tended to decrease in the low mountain forest zone of the northwestern and southeastern parts of Dongshan Island as well as in the coastal protection forest area. The areas where ECI became high were located in the northeastern part of Dongshan Island where cities and towns are concentrated with high human populations.Therefore, rapid urbanization has been the most important factor driving changes in landscape structure and patterns during the last 17 years on Dongshan Island. The approach not only assists us in revealing the driving mechanism of landscape dynamics from another aspect, but also can assess the impacts of regional and urban plans on landscape structure and function. 展开更多
关键词 Cost-distance model Dongshan Island Ecological connectivity Spatio-temporal dynamics
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Discretization Approach in Integrated Hydrologic Model for Surface and Groundwater Interaction 被引量:3
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作者 ZHANG Jing Mark A ROSS Jeffery GEURINK 《Chinese Geographical Science》 SCIE CSCD 2012年第6期659-672,共14页
The commonly used discretization approaches for distributed hydrological models can be broadly categorized into four types,based on the nature of the discrete components:Regular Mesh,Triangular Irregular Networks(TINs... The commonly used discretization approaches for distributed hydrological models can be broadly categorized into four types,based on the nature of the discrete components:Regular Mesh,Triangular Irregular Networks(TINs),Representative Elementary Watershed(REWs) and Hydrologic Response Units(HRUs).In this paper,a new discretization approach for landforms that have similar hydrologic properties is developed and discussed here for the Integrated Hydrologic Model(IHM),a combining simulation of surface and groundwater processes,accounting for the interaction between the systems.The approach used in the IHM is to disaggregate basin parameters into discrete landforms that have similar hydrologic properties.These landforms may be impervious areas,related areas,areas with high or low clay or organic fractions,areas with significantly different depths-to-water-table,and areas with different types of land cover or different land uses.Incorporating discrete landforms within basins allows significant distributed parameter analysis,but requires an efficient computational structure.The IHM integration represents a new approach interpreting fluxes across the model interface and storages near the interface for transfer to the appropriate model component,accounting for the disparate discretization while rigidly maintaining mass conservation.The discretization approaches employed in IHM will provide some ideas and insights which are helpful to those researchers who have been working on the integrated models for surface-groundwater interaction. 展开更多
关键词 DISCRETIZATION distributed hydrological model Integrated Hydrologic Model(IHM) INTERACTION
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Rocky Desertification Risk Zone Delineation in Karst Plateau Area:A Case Study in Puding County,Guizhou Province 被引量:15
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作者 ZHANG Panpan HU Yuanman +3 位作者 XIAO Duning LI Xiuzhen YIN Jie HE Hong S 《Chinese Geographical Science》 SCIE CSCD 2010年第1期84-90,共7页
Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management a... Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention. We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification. The potential risk of rocky desertification was quantifed with the factor-weights union method and statistical analysis method. Five grades of rocky desertification risk were delineated based on Geographic Information System. The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively. As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area. However, more than half of the area (about 50.81%) was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification. Rocky desertification risk was higher in the southeast and lower in the northwest of the study area. Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found. 展开更多
关键词 rocky desertification rocky desertification risk zone karst plateau Guizhou Province
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Soil Erosion under Different Land Use Types and Zones of Jinsha River Basin in Yunnan Province,China 被引量:13
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作者 YANGZisheng LIANGLuohui 《Journal of Mountain Science》 SCIE CSCD 2004年第1期46-56,共11页
Severe soil erosion in the middle and upper reaches of Yangtze River has been regarded as a major environmental problem. The on-site impact of soil erosion on agricultural production and the off-site impact on floods ... Severe soil erosion in the middle and upper reaches of Yangtze River has been regarded as a major environmental problem. The on-site impact of soil erosion on agricultural production and the off-site impact on floods and sedimentation in Yangtze Rive are well known. A quantitative assessment of soil erosion intensity is still scanty for developing appropriate soil erosion control measures for different land use types and zones in this region. This article constructs a localized USLE and estimates the average soil loss in the Jinsha River Region in Yunnan Province, one of the priority areas for soil erosion control in the middle and upper reaches of Yangtze River. The estimation is done under different land uses and zones in this basin. The estimation shows that while soil erosion in the cultivated land is the most severe, 36~40% of the garden and forest land suffers from soil erosion of various degrees due to lack of ground cover and other factors. Soil erosion in the pasture is modest when the ground cover is well maintained. It also confirmed that terracing can reduce soil erosion intensity significantly on the cultivated land. Research findings suggest that sufficient attention must be paid to regeneration of the ground cover in reforestation programs. In addition to mass reforestation efforts, restoration of grassland and terracing of the cultivated land should also play an important role in erosion control. 展开更多
关键词 Soil erosion soil loss equation land use type soil erosion control Jinsha River Basin in Yunnan
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Monitoring and Evaluation of Soil Changes Under Landuse of Different Patterns at a Small Regional Level in South China 被引量:11
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作者 WANGXIAOJU GONGZITONG 《Pedosphere》 SCIE CAS CSCD 1996年第4期373-378,共6页
MonitoringandEvaluationofSoilChangesUnderLanduseofDifferentPatternsataSmallRegionalLevelinSouthChinaWANGXIAO... MonitoringandEvaluationofSoilChangesUnderLanduseofDifferentPatternsataSmallRegionalLevelinSouthChinaWANGXIAOJUandGONGZITONG(I... 展开更多
关键词 EVALUATION geographical information system LANDUSE soil changes soil quality
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Spatial-temporal Pattern and Differences of Land Use Changes in the Three Gorges Reservoir Area of China during 1975-2005 被引量:9
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作者 CAO Yingui ZHOU Weit +1 位作者 WANG Jing YUAN Chun 《Journal of Mountain Science》 SCIE CSCD 2011年第4期551-563,共13页
Regional land use changes are an important part of global changes.The research on land use changes in the Three Gorges Reservoir Area of China attracts a lot of attention owing to the Three Gorges Dam building.The Thr... Regional land use changes are an important part of global changes.The research on land use changes in the Three Gorges Reservoir Area of China attracts a lot of attention owing to the Three Gorges Dam building.The Three Gorges Reservoir Area becomes one of the important research areas.This study analyzed the transforming processes and traits of each land use type and the regional differences of land use changes during the past 30 years,summarized the distribution of different land use types in different buffer zones and regresses the equation areas and different buffer distances based on buffer analyses and regression analyses,and then analyzed the transforming rules in different buffer distances,got the optimal influence distances.The research results indicate that,(1) cultivated land lies at the northwest of the reservoir and was decreasing,however,the construction land was increasing,especially the urban construction land,a large number of land was flooded because of the reservoir water level rise;(2) urban area was sprawling quickly in developed and neighboring areas,and a great deal of cultivated land and a considerable amount of grassland were occupied;in the earlier time,rural settlements occupied lots of cultivated land and a sum of forestry land in the later time;(3) the optimum influenced distances for cultivated land and forestry land were 10-35 km,and for urban and rural settlements were in 5-20 km.Overall,this research can reflect the spatial-temporal characteristics of land use changes during the 30 years,and it is helpful for urban planning and land use planning in the reservoir area. 展开更多
关键词 Land use Spatial-temporal changes DIFFERENCES Three Gorges Reservoir Area
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Efects of Cropland Cover Changes on Regional Climate over Western China Based on Simulations with RegCM3 被引量:2
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作者 SHI Xue-Li HE Hui-Juan REN Hong-Chang 《Advances in Climate Change Research》 SCIE 2013年第4期250-259,共10页
The impacts of land cover changes on regional climate with RegCM3. Sensitivity experiments were conducted by in Shaan-Gan-Ning (SGN) in western China were simulated replacing crop grids with different new land cover... The impacts of land cover changes on regional climate with RegCM3. Sensitivity experiments were conducted by in Shaan-Gan-Ning (SGN) in western China were simulated replacing crop grids with different new land cover types in the key area of SGN, where the returning cropland to tree/grass project has been carried out since 1999. The modified new land cover types include desert, forest, shrub and grass. They represent degraded, improved, and maintained vegetation cover with natural canopy in the key area. Results from three individual case studies show that the land cover change causes changes in temperature and terrestrial water variables especially within the key area, while changes in precipitation are found for a larger area. The strongest changes appear where the cropland is degraded to bare soil, leading to increasing temperature and decreases in rainfall, evaporation and soil water. Opposite changes occur when cropland changed into forests, especially with strong increases in soil water. When cropland changed to grass and shrub land, the climatic changes are closer to those with forest cover. This shows the importance of improving and maintaining the vegetation in SGN for the ecosystem and regional climate. 展开更多
关键词 land cover change REGCM3 regional climate
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Distribution and Assessment of Soil and Land Degradation in Subtropical China—A Case Study of the Dongxi River Basin, Fujian Province *1 被引量:7
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作者 PULIJIE D.L.HIGGITT 《Pedosphere》 SCIE CAS CSCD 1998年第3期201-210,共10页
Some alternative methods for estimating soil erosion rates rapidly were used to elucidate the relationship between the land use types and land degradation. The 137 Cs content, magnetic susceptibility, aggrega... Some alternative methods for estimating soil erosion rates rapidly were used to elucidate the relationship between the land use types and land degradation. The 137 Cs content, magnetic susceptibility, aggregate stability, and soil properties were studied in the Dongxi River Basin, a mountainous area of western Fujian. A plot of 137 Cs inventory (Y) against slope angle (X) shows a strong inverse log log relationship ( r = -0.83 ), indicating that much more soil erosion occurs on steeper slopes. Average soil loss (in thickness of top soil per year) in the past 30 years for arable slope crest, arable slopes and tea plantation slopes are 1.6 , 10.4 and 8.0 mm year -1 respectively. The surface layer enrichment factor of magnetic susceptibility (Y) in soil also shows an inverse log log relationship ( r =-0.63), indicating a similar tendency with the relationship between the 137 Cs inventory (Y) against slope angle (X). The physical and chemical properties of soils among different land use types show different degraded characteristics at different significant levels. 展开更多
关键词 Cs technique magnetic susceptibility soil and land degradation subtropical environment
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Spatial Analysis of Flood Vulnerability Levels in Port Harcourt Metropolis Using GIS 被引量:1
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作者 Olatunde Sunday Eludoyin Vincent Ezikomwor Weli 《Journal of Earth Science and Engineering》 2012年第10期617-623,共7页
The study identified spatial variations in flood vulnerability levels in Port Harcourt metropolis with the use of GIS (geographic information systems). This study considered four factors and these included landuse t... The study identified spatial variations in flood vulnerability levels in Port Harcourt metropolis with the use of GIS (geographic information systems). This study considered four factors and these included landuse types, drainage, residential densities and elevation. The elevation data and drainage data were derived from the topographical map of scale 1:35,000, while the land use types were derived from the imagery of Port Harcourt metropolis downloaded from Google Earth, 2010 version. Both the topographical map and imagery were geo-referenced to geographic coordinates and geographic features were digitized in form of shapefiles using both ArcView GIS 3.3 and ArcGIS 9.2 versions. AHP (analytical hierarchical process) was adopted in this study whereby many flood factors were ranked and overlaid for decision making. The contour data was used to generate the DEM (digital elevation model) through the process called kriging in ArcGIS 9.2. Based on the ranking index, factors considered were reclassified to three levels of vulnerability namely highly vulnerable, moderately vulnerable and lowly vulnerable through ranking method and these reclassified factors were then overlaid using an addition operator. The analysis shows that communities like Eagle Island, Ojimbo, Kidney Island were highly vulnerable to flood while communities like Choba, Ogbogoro, Rumualogu were moderately vulnerable. Communities like Rumuigbo, Rumuodomaya etc. were lowly vulnerable to flood. The highly vulnerable places covered 98.18 km2, moderately vulnerable was 220.46 km2 and lowly vulnerable areas covered 330.77 km2. 展开更多
关键词 Flood monitoring GIS ArcGIS 9.2 ArcView 3.3 KRIGING interpolation vulnerability.
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Quantitative Assessment of Impacts of Regional Climate and Human Activities on Saline-alkali Land Changes:A Case Study of Qian'an County,Jilin Province 被引量:3
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作者 LIAN Yi WANG Jie +5 位作者 TU Gang REN Hongling SHEN Baizhu ZHI Keguang LI Shangfeng GAO Zongting 《Chinese Geographical Science》 SCIE CSCD 2010年第1期91-97,共7页
Interdecadal and interannuat variations of saline-alkali land area in Qian'an County, Jilin Province, China were comprehensively analyzed in this paper by means of satellite remote sensing interpretation, field flux ... Interdecadal and interannuat variations of saline-alkali land area in Qian'an County, Jilin Province, China were comprehensively analyzed in this paper by means of satellite remote sensing interpretation, field flux observations and regional climate diagnosis. The results show that on the interannual scale, the impact of climate factors accounts for 71.6% of the total variation of the saline-alkali land area, and that of human activities accounts for 28.4%. Therefore the impact of climate factors is obviously greater than that of human activities. On the interdecadal scale, the impact of climate factors on the increase of the saline-alkali land area accounts for 43.2%, and that of human activities accounts for 56.8%. The impact of human activities on the variation of saline-alkali land area is very clear on the interdecadal scale, and the negative impact of human activities on the environment should not be negligible. Besides, changes in the area of heavy saline-alkali land have some indication for development of saline-alkali land in Qian'an County. 展开更多
关键词 saline-alkali land regional climate change human activities
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