基于多时相陆地卫星图像的锡林河流域土地覆盖类型特征

1IntroductionThe growing concern over the impact of changes in land use and land cover on environmental conditions and the increasing human impact on the natural resources has captured worldwide attention of the political and scientific community (Ojima etal., 1991; Smith etal., 2001). It is expected that the changing land use/land cover pattern will be one of the driving forces of environmental changes superimposed on the natural changes at regional scale (Fu etal., 1993; Bonan, 1995). Arid…     

美国土地利用/土地覆盖变化的空间特征

1IntroductionInrecentyears,studyonglobalchangehasbecomethefocus,onwhichstresshasbeenlaidbytodayhumansociety.Inordertodealwithseriesofenvironmentalproblemssuchasdegradationoflandresources,globalwarming,destructionofozonosphereandsoon,andassurethestabilizationandsustainabledevelopmentofworldeconomy,IGBPhasestablishedthestudyframeforglobalchange.Withavastrangeofstudy,researchonglobalchangehasbroughtforwardagreatdealofimportantscientificquestionsrelatedtofeasibilityforhumanelivingoftheEarth.Inth…     

近10年洞庭湖区土地利用变化时空特征

The research on the land use/cover change is one of the frontiers and the hot spots in the global change research. Based on the Chinese resource and environment spatial-temporal database,and using the Landsat TM and ETM data of 1990 and 2000 respectively, we analyzed the spatial-temporal characteristics of land use/cover changes in the Dongting Lake area during the last decade. The result shows that during the last ten years there were three land-use types that had changed remarkably. The cultivated land decreased by 0.57% of the total cultivated land. The built-up land and water area expanded, with an increase of 8.97% and 0.43% respectively. The conversion between land use types mostly happened among these three land-use types, especially frequently between cultivated land and water area. The land-use change speed of land-use type is different. Three cities experienced the greatest degree of land-use change among all the administrative districts, which means that the land use in these cities changed much quickly. The following changed area was the west and south of the Dongting Lake area. The slowest changed area is the north and east area.     

20世纪90年代中国土地利用变化时空特征及其成因分析

在土地利用变化时空信息平台的支持下,本文对我国20世纪80年代末到90年代末的土地利用变化过程进行了全面分析,揭示了我国10年来土地利用变化的时空规律,分析了这些规律形成的主要政策、经济和自然成因。研究表明,20世纪90年代,全国耕地总面积呈北增南减、总量增加的趋势,增量主要来自对北方草地和林地的开垦。林业用地面积呈现总体减少的趋势,减少的林地主要分布于传统林区,南方水热充沛区造林效果明显。中国城乡建设用地整体上表现为持续扩张的态势。90年代后5年总体增速减缓,西部增速加快。20世纪90年代我国的土地利用变化表现出明显的时空差异,政策调控和经济驱动是导致土地利用变化及其时空差异的主要原因。据此,本文提出在今后的全国土地利用规划中,应充分考虑我国现代土地利用变化的区域分异规律。同时,在生态环境恢复与建设规划中也应强调自然地理地带的针对性,同时要改变传统的资源规划与管理思路,在基础设施日益完备的条件下,最大程度地发挥跨区域土地资源优化配置的综合优势     

基于Landsat TM/ETM数据的锡林河流域土地覆盖变化

根据1987年、1991年、1997年和2000年4期Landsat TM/ETM影像的土地利用/土地覆盖分类结果,运用地理信息系统空间分析方法,分析了内蒙古锡林河流域1987~2000年间各土地利用类型及草甸草原、典型草原、荒漠草原的数量变化和空间变化特征。分析结果显示,锡林河流域土地利用/土地覆盖变化的主要特征为草甸草原、典型草原面积的大幅减少和荒漠草原、农田和沙漠化土地面积的大幅增加及城镇的扩张。其中面积增加最大的是荒漠草原,增加了2328 km²;相当于1987年荒漠草原面积的56 %。农田和城镇面积逐年增大,分别从1987年的114.3 km²和25.2 km²增加到2000年的332.1 km²和43.6 km²。面积减少最多的是羊草＋丛生禾草、羊草＋杂类草等优良高产温带典型草原类型,共减少2040 km²。草甸草原面积亦呈逐年减少的趋势,从1987年的1103 km²减少到2000年375 km²,面积减少了65.9 %。农田、沙化地及城镇等非草原土地利用类型面积增加了62.5 %。     

近期气候波动与LUCC过程对东北农田生产潜力的影响

利用1991~2000年逐日气象资料以及20世纪80年代末和90年代末土地利用数据,估算了东北地区气候波动和LUCC过程对农田生产潜力的影响。结果显示:90年代东北地区由于作物生长季内气候变暖和降水减少,生产潜力普遍降低6.45%,其中降水量变化的区域差异是导致生产潜力变化区域分异的主要原因。在LUCC过程的影响下,东北地区生产潜力总量净增加2 402.79×10⁴t。从气候波动和LUCC过程对生产潜力的影响程度看,气候波动要低于LUCC过程的作用,LUCC过程所导致的生产潜力的增长趋势抵消了气候波动所带来的降低趋势,10年间东北地区农田生产潜力总量净增加992.23×10⁴t。     

退耕还林还草工程对黄土高原植被总初级生产力的影响

采用Landsat解译的2000年和2015年土地利用/覆盖数据和VPM模型（Vegetation Photosynthesis Model）模拟的2000~2016年总初级生产力（Gross Primary Productivity, GPP）数据,识别出了近16 a黄土高原退耕还林还草的空间范围,并估算了GPP的年际变化趋势。在此基础上,对比分析了退耕区和未退耕区GPP年际变化的差异,从而揭示退耕还林还草工程对GPP年际变化的影响。结果显示,2000~2015年,黄土高原退耕还林还草面积约3.5万km ²,占2000年耕地面积的16.8%。期间,GPP呈增加趋势,GPP显著上升区域占全区面积的67.3%,平均增速24.1 g/(m ²?a)（以C计,下同）。虽然退耕区多年平均GPP低于未退耕区,但退耕区GPP年际增速和相对变化率明显高于未退耕区,分别提高了5.9 g/(m ²?a)和1.5%。     

20世纪80年代以来中国土地利用变化的基本特征与空间格局(英文)

Land-use/land-cover changes(LUCCs) have links to both human and nature interactions. China's Land-Use/cover Datasets(CLUDs) were updated regularly at 5-year intervals from the late 1980s to 2010, with standard procedures based on Landsat TM\ETM+ images. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics, differences, and causes of land-use changes at a national scale were then examined. The main findings are summarized as follows. Land-use changes(LUCs) across China indicated a significant variation in spatial and temporal characteristics in the last 20 years(1990–2010). The area of cropland change decreased in the south and increased in the north, but the total area remained almost unchanged. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly, were mainly distributed in the east, and gradually spread out to central and western China. Woodland decreased first, and then increased, but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included(1) an accelerated expansion of built-up land in theHuang-Huai-Hai region, the southeastern coastal areas, the midstream area of the Yangtze River, and the Sichuan Basin;(2) shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China;(3) continuous transformation from rain-fed farmlands in northeast China to paddy fields; and(4) effectiveness of the "Grain for Green" project in the southern agricultural–pastoral ecotones of Inner Mongolia, the Loess Plateau, and southwestern mountainous areas. In the last two decades, although climate change in the north affected the change in cropland, policy regulation and economic driving forces were still the primary causes of LUC across China. During the first decade of the 21st century, the anthropogenic factors that drove variations in land-use patterns have shifted the emphasis from one-way land development to both development and conservation. The "dynamic regionalization method" was used to analyze changes in the spatial patterns of zoning boundaries, the internal characteristics of zones, and the growth and decrease of units. The results revealed "the pattern of the change process," namely the process of LUC and regional differences in characteristics at different stages. The growth and decrease of zones during this dynamic LUC zoning, variations in unit boundaries, and the characteristics of change intensities between the former and latter decades were examined. The patterns of alternative transformation between the "pattern" and "process" of land use and the causes for changes in different types and different regions of land use were explored.     

1990–2010年中国土地覆被变化引起反照率改变的辐射强迫(英文)

Land cover change affects surface radiation budget and energy balance by changing surface albedo and further impacts the regional and global climate. In this article, high spatial and temporal resolution satellite products were used to analyze the driving mechanism for surface albedo change caused by land cover change during 1990–2010. In addition, the annual-scale radiative forcing caused by surface albedo changes in China's 50 ecological regions were calculated to reveal the biophysical mechanisms of land cover change affecting climate change at regional scale. Our results showed that the national land cover changes were mainly caused by land reclamation, grassland desertification and urbanization in past 20 years, which were almost induced by anthropogenic activities. Grassland and forest area decreased by 0.60% and 0.11%, respectively. The area of urban and farmland increased by 0.60% and 0.19%, respectively. The mean radiative forcing caused by land cover changes during 1990–2010 was 0.062 W/m2 in China, indicating a warming climate effect. However, spatial heterogeneity of radiative forcing was huge among different ecological regions. Farmland conversing to urban construction land, the main type of land cover change for the urban and suburban agricultural ecological region in Beijing-Tianjin-Tangshan region, caused an albedo reduction by 0.00456 and a maximum positive radiative forcing of 0.863 W/m2, which was presented as warming climate effects. Grassland and forest conversing to farmland, the main type of land cover change for the temperate humid agricultural and wetland ecological region in Sanjiang Plain, caused an albedo increase by 0.00152 and a maximum negative radiative forcing of 0.184 W/m2, implying cooling climate effects.     

中国城市群分布及范围的定量评价(英文)

Urban clusters are the expected products of high levels of industry and urbanization in a country, as well as being the basic units of participation in global competition. With respect to China, urban clusters are regarded as the dominant formation for boosting the Chinese urbanization process. However, to date, there is no coincident, efficient, and credible methodological system and set of techniques to identify Chinese urban clusters. This research investigates the potential of a computerized identification method supported by geographic information techniques to provide a better understanding of the distribution of Chinese urban clusters. The identification method is executed based on a geographic information database, a digital elevation model, and socio-economic data with the aid of ArcInfo Macro Language programming. In the method, preliminary boundaries are identified accord-ing to transportation accessibility, and final identifications are achieved from limiting city numbers, population, and GDP in a region with the aid of the rasterized socio-economic dataset. The results show that the method identifies nine Chinese urban clusters, i.e., Pearl River Delta, Lower Yangtze River Valley, Beijing-Tianjin-Hebei Region, Northeast China Plain, Middle Yangtze River Valley, Central China Plains, Western Taiwan Strait, Guanzhong and Chengdu-Chongqing urban clusters. This research represents the first study involving the computerized identification of Chinese urban clusters. Moreover, compared to other related studies, the study’s approach, which combines transportation accessibility and socio-economic characteristics, is shown to be a distinct, effective and reliable way of identifying urban clusters.