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1.
由于人口的增长和经济的快速发展,发展中国家正经历着日益剧烈的土地利用变化,其变化的范围不仅发生在平原,甚至已经扩展到山区。作为山区基本的地理单元,沟域是山区经济活动的主要场所、因此,沟域土地利用的优化调控对山区绿色化发展至关重要。本文基于1995年和2012年北京山区的土地利用数据,系统分析了沟域的土地利用变化情况,同时根据典型沟域地形因子(如海拔和坡度)的土地利用变化评估结果,提出土地利用的优化调控路径。研究结果表明,沟域是评估山区土地利用变化趋势的有效地理单元,可以为未来山区的绿色化展提供科学依据。从1995年到2012年,北京山区沟域最显著的土地利用变化表现在草地面积的减少和建筑面积的增加(草地转换为建筑用地),而这些土地利用变化主要发生在海拔0-400米和坡度6-15°的区域范围内。考虑到近年来北京山区经济的快速发展,建筑用地和耕地的数量将会持续增加,但目前的结果显示地形较陡区域土地利用变化最为显著,意味着未来山区沟域土地利用优化调控应充分考虑地形因子的影响,在这些区域的土地利用政策中要着重考虑实施保障山区生态屏障和水土涵养的功能设施。  相似文献   

2.
To control soil erosion and restore the degraded environment in the Loess Plateau, a large number of measures related to soil and water conservation have been employed that have profoundly affected catchment properties. This study constructed three indicators to characterize changes to the catchment slope, proposed both a method for a regression analysis of adjacent images and a sequence model, and applied multisource remotely sensed images and GIS spatial clustering analysis technologies to extract thematic information and comprehensively analyze the catchment change characteristics. The results indicate that the catchment slope properties changed significantly. At catchment scale, the average values of ARC, DVC and ART were 6.43%, 25.57% and 4.30%, respectively. There were six clustering types of catchment slope property changes. The maximum and minimum of the average similarities of the clustering types were 0.992 and 0.935. Each slope control measures had a distinct effect on catchment slope; the dominating factor of each clustering type was identified as: Type 1: D-VC, Type 2: D-VCLU, Type 3: D-LUVC, Type 4: D-TAVC, Type 5: D-TAC and Type 6: D-MFC. Type 5 and Type 1 covered the largest areas, respectively occupying 37.28% and 31.01%. Catchment slope property changes also had distinct types that depended on their geomorphological conditions. These findings provide a useful basis from which to further study catchment slope hydrological and soil erosion processes.  相似文献   

3.
为了探讨山区表层土壤水分的空间分布格局及其影响因素,以北京市怀柔区为研究区域,联合使用ALOS/PA-LSAR微波数据和Landsat-5遥感影像反演得到研究区的土壤水分数据,运用旋转主成分分析法分析了高程、坡度、坡向和植被盖度4个环境因子对土壤水分的影响情况及分布规律,并确定相应的主控因子.结果表明:高程和坡度是影响山区表层土壤水分空间变异的主控因子,植被盖度次之,坡向的影响最弱.对主控因子(高程和坡度)的单因素分析表明,土壤含水量随着高程的增加而逐渐减少,随着坡度的增加,土壤含水量总体上呈现先增加(坡度<3°)后减小(坡度>3°)的趋势,对深入研究山区土壤水分分布特性和水土保持具有指导意义.  相似文献   

4.
草地净初级生产力(NPP)的空间格局受到各种环境要素的影响。当前大量研究探讨了不同环境变量对草地NPP的影响,但各种环境变量对其空间格局影响的相对重要性尚未统一结论。而基于模型模拟的草地NPP会加剧这一不确定性。因此,本研究基于文献资料搜集获得我国北方草地602个样点的生物量和产草量数据,构建1980-1999年草地NPP实测数据库。在此基础上,采用相关分析和主导因素分析法定量探讨了环境变量对NPP空间变异的单独和联合影响。研究表明,北方草地NPP的空间分布明显异质,在4.76 g Cm~(–2)a~(–1) to 975.94 g Cm~(–2)a~(–1)间波动。草地NPP与年降水量显著正相关,而与年均温度显著负相关,其中降水对荒漠草地的影响最大,其次为草原和草甸。由于水资源的限制,随着海拔的增加草地NPP降低。草地NPP与坡度呈正相关,与坡度的关系微弱。土壤质量越好,草地NPP越大。就各种环境要素的联合影响而言,年降水量是影响草地NPP空间格局的最主导要素,其次是高程。  相似文献   

5.
在较大区域内,城市用地扩张和农村土地利用发展一般同步进行。为了能够正确理解这类区域内土地利用/土地覆被变化的动力机制,本研究开发了一个基于多主体系统的土地利用模型。模型将鄱阳湖区视为一个典型区域,利用有限扩散聚合算法模拟城市主体的行为,采用基于涌现理论的主体模型模拟农村土地利用。农村子模型包括多种类型的主体和环境影响层,其中最重要的是农户主体,农户主体可以根据自身条件和周围的环境影响参数确定下一步土地利用的决策,政府主体则通过实施不同的政策对土地利用进行宏观控制。我们根据农户总收入和外出务工人员比例将农户主体分为6类,每种类型的农户主体遵循不同的决策规则。结果表明,本模型的模拟结果与鄱阳湖区1985 – 2005年的土地利用/土地覆被变化趋势高度相符。尤其重要的是,模拟结果充分表明农户主体的土地利用决策与国家政策紧密相关。这表明本研究建立的基于多主体的土地利用模型是一种评估政府土地管理政策效果的有效手段。  相似文献   

6.
本文通过多尺度分解途径分析了NDVI与环境因子如地形与气候之间的空间尺度依存关系。为了揭示两者关系的尺度效应,选取青藏高原北纬32.5度作为研究样带,应用小波变换分析了不同空间尺度下的小波一致性和相位关系。研究结果表明:在青藏高原小于80km空间尺度上,气候变量如降水和气温不是控制NDVI的主导因素;而大于这个尺度,在一些生态区可以发现NDVI和气候因子具有显著的小波一致性。作为一个分异因子,海拔高度在青藏高原东南缘的纵向岭谷区对NDVI有着显著影响。通过这一研究发现,小波变换是研究NDVI与影响因素之间多尺度关系的一个有力途径。  相似文献   

7.
刘宇  傅伯杰 《干旱区地理》2013,36(6):1097-1102
基于16 d合成MODIS NDVI数据提取的时间序列植被覆盖度数据,采用一元线性回归趋势分析,对黄土高原2000-2008年植被覆盖度的时空变化及其地形分异、土地利用/覆被变化的影响进行了定量分析。结果表明:(1)研究时段黄土高原植被覆盖度整体呈快速上升趋势,局部下降;(2)黄土高原植被覆盖度变化存在明显的地形分异,陡坡等植被恢复、重建和保育的主要区域植被覆盖度增速显著;(3)土地利用/覆被变化对植被覆盖度的增加影响突出,土地利用/覆被类型变更区植被覆盖度增速显著高于未变化区域,退耕还林还草区增速尤其突出;(4)土地利用/覆被类型未变化区域植被覆盖度总体上也呈增加趋势,但因植被覆盖度水平相对较高,增速明显低于土地利用/覆被类型变化区。上述结果表明,黄土高原植被保育、植被恢复和重建在植被覆盖度提升方面取得了明显成效。  相似文献   

8.
1987-2007年土耳其伊斯坦布尔黑海沿岸土地利用变化(英文)   总被引:1,自引:0,他引:1  
Recently,important land use changes have occurred in the Black Sea coastal regions of stanbul due to urban growth and population increases.The objective of this study was to determine changes in land use in the Black Sea coastal regions of stanbul between 1987 and 2007.Landsat 30 m satellite images from 1987 and 2007 are used in the study.The study area is 1000 m in width from the coastline to the land and the study has been carried out using the controlled classification method to classify areas into residential,agricultural,forest,bare land,brush/grassland,and lake/pond land classes.Land use changes between 1987 and 2007 were analysed in detail.Residential areas of the Black Sea coastal regions of stanbul increased by 122% over the two decades.Also an increase of 55% in agriculture areas was observed,while there were decreases of 26% in forest areas and 15% in free land.A 21% increase in the area of brush and grassland took place.Furthermore 79% of the study area was covered by residential areas in 2007.It is probable that pressure on the stanbul coastal regions will continue due to migraton and rapid urbanization.Therefore,Istanbul’s Black Sea coastal regions should be maintained using a sustainable coastal management plan.  相似文献   

9.
土地利用/覆被变化对海岸环境演变影响的研究进展   总被引:5,自引:1,他引:5  
土地利用/覆被变化是影响海岸带环境演变的一个重要方面。文章着重从土地利用/覆被变化对温室气体释放、入海物质通量、生物多样性影响以及海岸特有自然覆被的生态环境效应角度评述了土地利用/覆被变化对海岸环境演变影响研究的内容与进展。分析指出该领域未来研究将朝更宏观综合(全球环境影响)与更微观深入(环境生物地球化学过程)两个趋向发展。可持续土地利用评价与调整、海岸环境生物地球化学过程与模拟、海岸生物多样性保护和海岸带综合管理将成为未来研究的重点。  相似文献   

10.
从GIS空间关系角度分析,区别于前人通过生态学中土壤质地、生物量、碳存储、氧释放量和水体质量等微观层面评估生态系统服务价值,以地理空间数据为基础,空间分析为核心技术,对浏阳河流域生态系统服务价值的空间异质性进行了研究。首先以1×1 KM格网形式将流域划分,然后将地形、地质灾害点、道路、景点、关心点等人类活动热点分布以及植被覆盖度、植物净初级生产力作为影响因子,然后结合熵值法和层次分析法计算这些因子对生态系统每个服务价值的权重,权重可以反映对生态系统服务价值的影响的程度。受空间异质性影响每个格网都具有不同的空间特征,格网中土地利用类型种类数量不一,存在多种土地类型的格网就构成了微型景观,其复杂的物种组成,稳定的内部结构,提高自身调节,生态系统稳定性也就增强,因此这种景观格局方式使格网内生态服务总价值应该大于各生态系统服务价值代数累加之和。研究发现:9个指标因子中植被覆盖度、植物净初级生产力和道路分布情况对生态服务价值影响最显著,植被覆盖度高、植物净初级生产能力强,道路网密集会提高生态系统服务价值;不同土地类型主要的生态系统服务也不一样:耕地、草地和水体的供给服务、调节服务突出,林地的调节和支持服务突出;在各地类中,耕地和水体生态服务价值受空间异质性影响较大,因为耕地和水体与人类活动密切相关,受自然和人类双重因素影响,而林地和草地由于多位于远离人类的山地和丘陵区,主要受生物和地理环境影响,受空间异质性影响相对较弱。本研究针对生态系统服务价值评估,定量分析每个格网的自然和社会特征因素对生态服务价值估算影响,为精确科学评估生态服务价值提供参考。  相似文献   

11.
胶东地区主要土地利用变化类型与影响因子的关系   总被引:1,自引:0,他引:1  
土地利用变化驱动机制研究是地理学研究的热点,而研究土地利用变化与影响因子关系是揭示土地利用变化驱动机制的关键。胶东地区是社会经济发展迅速的地区,选取该地区作为土地利用变化与影响因子关系研究区域具有重要的理论和现实意义。把胶东地区20世纪80年代和2000年的土地利用矢量数据相叠加,提取出主要土地利用类型发生变化的区域,统计出各变化类型的面积及其占总变化面积的比例,并构建出土地利用变化样本数据矩阵。把土地利用变化数据与胶东地区的城镇位置、道路、DEM、人口密度、GDP和海岸线位置等数据进行叠加分析,提取出土地利用变化图斑的影响因子,构建出土地利用变化的影响因子矩阵。在此基础上,应用典范对应分析方法(CCA)研究胶东地区土地利用变化与其影响因子的关系。结果显示,城镇化、建设用地扩展和耕地大量减少是该时期胶东地区土地利用变化的主要特点。人口密度、到城镇距离、高程和到主要公路距离是决定胶东地区主要土地利用变化类型分布的主要影响因子,其次为GDP和到海岸线距离。耕地转化为城镇用地和农村居民点转化为城镇用地多分布在人口密度大、GDP高、到城镇距离近和到主要公路距离近的区域;耕地转化为农村居民点多分布在海拔低、到城镇距离较近和到主要公路距离较近的区域。  相似文献   

12.
Understanding long-term human-environment interactions requires historical reconstruction of past land-use and land-cover changes. Most reconstructions have been based primarily on consistently available and relatively standardized information from historical sources. Based on available data sources and a retrospective research, in this paper we review the approaches and methods of the digital reconstruction and analyze their advantages and possible constraints in the following aspects:(1) Historical documents contain qualitative or semi-quantitative information about past land use, which also usually include land-cover data, but preparation of archival documents is very time-consuming.(2) Historical maps and pictures offer visual and spatial quantitative land-cover information.(3) Natural archive has significant advantages as a method for reconstructing past vegetation and has its unique possibilities especially when historical records are missing or lacking, but it has great limits of rebuilding certain land-cover types.(4) Historical reconstruction models have been gradually developed from empirical models to mechanistic ones. The method does not only reconstruct the quantity of land use/cover in historical periods, but it also reproduces the spatial distribution. Yet there are still few historical land-cover datasets with high spatial resolution.(5) Reconstruction method based on multiple-source data and multidisciplinary research could build historical land-cover from multiple perspectives, complement the missing data, verify reconstruction results and thus improve reconstruction accuracy. However, there are challenges that make the method still in the exploratory stage. This method can be a long-term development goal for the historical land-cover reconstruction. Researchers should focus on rebuilding historical land-cover dataset with high spatial resolution by developing new models so that the study results could be effectively applied in simulations of climatic and ecological effects.  相似文献   

13.
In response to the strong drive for social and economic development, local governments have implemented urban master plans, providing measures and timeframes to address the continuous demand for land and to alleviate urban problems. In this paper, a multi-objective model was constructed to discuss the problem, including economic benefits and ecological effectiveness, in terms of land use optimization. A genetic algorithm was then adopted to solve the model, and a performance evaluation and sensitivity analysis were conducted using Pareto optimality. Results showed that a set of tradeoffs could be acquired by the allocation of land use. In addition, the Pareto solutions proved the model to be efficient; for example, a limit of 13,500 ha of urban area conformed to plan recommendations. The reduction in crop land, orchard land, grassland, and unused land provided further efficiencies. These results implied that further potential regional land resources remain and that the urban master plan is able to support sustainable local development in the years to come, as well as verified that it is feasible to use land use allocation multi-objective modeling and genetic algorithms.  相似文献   

14.
东莞地区土地利用变化预测的CBR和CA方法对比研究(英文)   总被引:3,自引:0,他引:3  
Many studies on land use change(LUC),using different approaches and models,have yielded good results.Applications of these methods have revealed both advantages and limitations.However,LUC is a complex problem due to influences of many factors,and variations in policy and natural conditions.Hence,the characteristics and regional suitability of different methods require further research,and comparison of typical approaches is re-quired.Since the late 1980s,CA has been used to simulate urban growth,urban sprawl and land use evolution successfully.Nowadays it is very popular in resolving the LUC estimating problem.Case-based reasoning(CBR),as an artificial intelligence technology,has also been employed to study LUC by some researchers since the 2000s.More and more researchers used the CBR method in the study of LUC.The CA approach is a mathematical system con-structed from many typical simple components,which together are capable of simulating complex behavior,while CBR is a problem-oriented analysis method to solve geographic problems,particularly when the driving mechanisms of geographic processes are not yet understood fully.These two methods were completely different in the LUC research.Thus,in this paper,based on the enhanced CBR model,which is proposed in our previous research(Du et al.2009),a comparison between the CBR and CA approaches to assessing LUC is presented.LUC in Dongguan coastal region,China is investigated.Applications of the im-proved CBR and the cellular automata(CA) to the study area,produce results demonstrating a similarity estimation accuracy of 89% from the improved CBR,and 70.7% accuracy from the CA.From the results,we can see that the accuracies of the CA and CBR approaches are both >70%.Although CA method has the distinct advantage in predicting the urban type,CBR method has the obvious tendency in predicting non-urban type.Considering the entire ana-lytical process,the preprocessing workload in CBR is less than that of the CA approach.As such,it could be concluded that the CBR approach is more flexible and practically useful than the CA approach for estimating land use change.  相似文献   

15.
The spatio-temporal pattern of the global water resource has significantly changed with climate change and intensified human activities. The regional economy and ecological environment are highly affected by terrestrial water storage(TWS), especially in arid areas. To investigate the response relationships between TWS and changing environments(climate change and human activities) in Central Asia, we used the Gravity Recovery and Climate Experiment(GRACE) data, Climatic Research Unit(CRU) climate data and Moderate Resolution Imaging Spectroradiometer(MODIS) remote sensing data products(MOD16A2, MOD13A3 and MCD12Q1) from 2003 to 2013, as well as the slope and Pearson correlation analysis methods. Results indicate that:(1) TWS in about 77% of the study area decreased from 2003 to 2013. The total change volume of TWS is about 2915.6 × 108 m~3. The areas of decreased TWS are mainly distributed in the middle of Central Asia, while the areas of increased TWS are concentrated in the middle-altitude regions of the Kazakhstan hills and Tarim Basin.(2) TWS in about 5.91% of areas, mainly distributed in the mountain and piedmont zones, is significantly positively correlated with precipitation, while only 3.78% of areas show significant correlation between TWS and temperature. If the response time was delayed by three months, there would be a very good correlation between temperature and TWS.(3) There is a significantly positive relationship between TWS and Normalized Difference Vegetation Index(NDVI) in 13.35% of the study area.(4) The area of significantly positive correlation between TWS and evapotranspiration is about 31.87%, mainly situated in mountainous areas and northwestern Kazakhstan. The reduction of regional TWS is related to precipitation more than evaporation. Increasing farmland area may explain why some areas show increasing precipitation and decreasing evapotranspiration.(5) The influences of land use on TWS are still not very clear. This study could provide scientific data useful for the estimation of changes in TWS with climate change and human activities.  相似文献   

16.
Land use and land cover change(LULCC) strongly influence regional and global climate by combining both biochemical and biophysical processes. However, the biophysical process was often ignored, which may offset the biogeochemical effects, so measures to address climate change could not reach the target. Thus, the biophysical influence of LULCC is critical for understanding observed climate changes in the past and potential scenarios in the future. Therefore, it is necessary to identify the mechanisms and effects of large-scale LULCC on climate change through changing the underlying surface, and thus the energy balance. The key scientific issues on understanding the impacts of human activities on global climate that must be addressed including:(1) what are the basic scientific facts of spatial and temporal variations of LULCC in China and comparative countries?(2) How to understand the coupling driving mechanisms of human activities and climate change on the LULCC and then to forecasting the future scenarios?(3) What are the scientific mechanisms of LULCC impacts on biophysical processes of land surface, and then the climate?(4) How to estimate the contributions of LULCC to climate change by affecting biophysical processes of land surface? By international comparison, the impacts of LULCC on climate change at the local, regional and global scales were revealed and evaluated. It can provide theoretical basis for the global change, and have great significance to mitigate and adapt to global climate changes.  相似文献   

17.
18.
杨萍  叶玮 《中国沙漠》2013,33(6):1670-1677
古土壤是发育于地质历史时期埋藏的自然土壤,是记录古环境信息的重要载体。本文基于对内蒙古沙区古土壤研究文献的梳理,通过古土壤测年数据统计,对比区内其他信息载体的研究成果,分析内蒙古沙区沙漠/沙地形成时代及全新世环境变化。结果表明:内蒙古沙区全新世环境变化可分为3个阶段:全新世早期(10~8.5 ka BP)为升温阶段,气候以干冷为主;全新世中期(8.5~2.5 ka BP)为气候适宜期,古土壤普遍发育,同时存在短期干冷波动;全新世晚期(2.5 ka BP以来)为降温期,气候逐步干冷,部分沙地气候波动频繁,形成古土壤。  相似文献   

19.
The environmental impact assessment (EIA) of cascade dams building in international rivers has been widely discussed in China and ASEAN countries since the 1990s. In Southwest China, all the great mountainous rivers have been the major state base for large-scale hydropower development. Among these rivers, the environmental change and response of the watercourse under the cascade dams building in the upper Mekong (called Lancang River in China) has been the focus in recent 20 years. In this paper, the Lancang River, which has over 25 years of large-scale hydropower development, was chosen as a case study for establishing the affected evaluation indicators system and its regression model of runoff and sediment, determining the indicators weight by the hierarchy analysis method and factor analysis method, and setting up the quantitative evaluation models of indicators affected level based on the "marginal efficiency" principle. Using these methods and model established, the influence degree of runoff and sediment in the Lancang River from 1986 to 2007 were assessed. The major results are: (1) the impact of sediment transport change by the cascade development is much higher than that of the runoff change; (2) the years’ number with different impact levels respectively are 72.7% as the "smallest" level, 18.2% as "smaller", and 9.1% as "general"; (3) the change process of runoff and sediment shows a "U-shaped" pattern, which indicates the balance of sediment change because of the interaction of sediment reduction by Manwan reservoir storage and the increase by the Dachaoshan dam construction.  相似文献   

20.
苏州城郊土地利用变化对土壤的影响   总被引:3,自引:0,他引:3  
1IntroductionThe conversion of natural systems to agricultural production has been the primary basis for the successful growth of human populations for the last 9,000 years (Kates etal., 1990). The conflict between urban and agricultural land use, however…  相似文献   

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