Changing landscape in the Three Gorges Reservoir Area of Yangtze River from 1977 to 2005: Land use/land cover,vegetation cover changes estimated using multi-source satellite data

The eco-environment in the Three Gorges Reservoir Area (TGRA) in China has received much attention due to the construction of the Three Gorges Hydropower Station. Land use/land cover changes (LUCC) are a major cause of ecological environmental changes. In this paper, the spatial landscape dynamics from 1978 to 2005 in this area are monitored and recent changes are analyzed, using the Landsat TM (MSS) images of 1978, 1988, 1995, 2000 and 2005. Vegetation cover fractions for a vegetation cover analysis are retrieved from MODIS/Terra imagery from 2000 to 2006, being the period before and after the rising water level of the reservoir. Several analytical indices have been used to analyze spatial and temporal changes. Results indicate that cropland, woodland, and grassland areas reduced continuously over the past 30 years, while river and built-up area increased by 2.79% and 4.45% from 2000 to 2005, respectively. The built-up area increased at the cost of decreased cropland, woodland and grassland. The vegetation cover fraction increased slightly. We conclude that significant changes in land use/land cover have occurred in the Three Gorges Reservoir Area. The main cause is a continuous economic and urban/rural development, followed by environmental management policies after construction of the Three Gorges Dam.     

Analysis and simulation of land use spatial pattern in Harbin prefecture based on trajectories and cellular automata—Markov modelling

There have been rapid population and accelerating urban growth with associated changes in land use and soil degradation in northeast China, an important grain-producing region. The development of integrated use of remote sensing, geographic information systems, and combined cellular automata– Markov models has provided new means of assessing changes in land use and land cover, and has enabled projection of trajectories into the future. We applied such techniques to the prefecture-level city of Harbin, the tenth largest city in China. We found that there had been significant losses of the land uses termed “cropland”, “grassland”, “wetland”, and “floodplain” in favour of “built-up land” and lesser transformations from “floodplain” to “forestland” and “water body” over the 18-year period. However, the transition was not a simple process but a complex network of changes, interchanges, and multiple transitions. In the absence of effective land use policies, projection of past trajectories into a balance state in the future would result in the decline of cropland from 65.6% to 46.9% and the increase of built-up area from 7.7% to 23.0% relative to the total area of the prefecture in 1989. It also led to the virtual elimination of land use types such as unused wetland and floodplain.     

基于GEE平台的1991-2020年环洱海地带土地利用时空变化分析

洱海作为我国重点保护湖泊“新三湖”之一,近30年间环洱海地带经济发展与人地矛盾的问题日益突出. 研究环洱海地区长时间序列的土地利用变化规律,分析人类活动的影响程度对保护治理洱海具有重要意义. 基于谷歌地球引擎(GEE)云平台,以1991—2020年7期Landsat TM/OLI影像为基础数据,融合光谱、归一化差异指数和增强型植被指数等特征,采用随机森林方法对环洱海10 km范围进行了土地利用分类,结合土地利用变化图谱、人类活动指数模型定量分析了城镇化背景下环洱海地带土地利用类型的演变趋势及人类活动强度. 结果表明:1991—2020年林地、草地面积整体呈减少趋势,主要转出方向为耕地;建设用地面积持续增长,主要转入来源为耕地;水域面积变化较小,湿地呈先增加后减少趋势,上述变化趋势与环洱海地区城镇化快速推进有关;人类活动强度总体逐年上升,以低影响区为主且保持相对稳定.高影响区和中高影响区主要集中于环湖南侧和环湖西侧,中低影响区呈零星块状分布且一直呈减少趋势.      

天津滨海新区土地利用变化及驱动因子分析

随着全球变化研究的深入,人们逐渐认识到人类活动所导致的土地利用/土地覆盖变化(Land Use and Cover Change)最终会反过来影响到人类自身的生存和发展。因此,土地利用与土地覆盖变化成为全球变化研究的热点问题。本文以天津滨海新区为研究区域,使用ENVI软件通过面向对象解译的方法分别对2005、2010、2014年的遥感图像进行处理,得到3期的解译数据;然后,运用土地利用动态度及土地利用转移矩阵的方法对土地利用的面积变化情况进行分析;最终得出结论:该区域土地利用类型面积变化以建筑用地、未利用地的大幅增加及水域的锐减为主。2005~2014年9年间建筑用地和未利用地面积增加量分别为13 638.15 hm~2、6 926.94 hm~2;植被和盐田的面积都是减少的,而植被减少的面积最多,减少的面积量为10 673.28 hm~2。同时,本文进一步分析了经济、人口、政策驱动因子对该区域土地利用变化的影响。     

基于GIS和RS的延安地区土地利用及生态脆弱性评价

基于延安市8个区县1997年、2004年和2011年的TM影像数据,运用遥感和地理信息系统软件,对延安地区自退耕还林(草)政策实施以来土地利用动态变化的数量、速度及其空间格局特征进行了定量分析,并结合经济、社会和自然因素数据,通过主成分分析法对延安地区生态脆弱性进行评价。结果表明,1997年至2011年,延安地区的土地利用类型发生了很大变化。耕地面积呈现减少的趋势;居民用地面积处于增长的态势;林地面积增加,并且后期的增加速度明显大于前期;草地面积有小幅度的减少;未利用地和水体面积呈先减少后增加的趋势。生态脆弱性评估表明,在延安地区的8个区县中,北部四县的生态脆弱性指数比南部四县高。在1997年至2011年期间,研究区域内生态环境脆弱性指数逐渐减小,生态环境安全性逐渐增强。     

Abrupt spatiotemporal land and water changes and their potential drivers in Poyang Lake, 2000–2012

Driven by various natural and anthropogenic factors, Poyang Lake, the largest freshwater lake in China, has experienced significant land use/cover changes in the past few decades. The aim of this study is to investigate the spatial–temporal patterns of abrupt changes and detect their potential drivers in Poyang Lake, using time-series Moderate Resolution Imaging Spectroradiometer (MODIS) 16-day maximum value composite vegetation indices between 2000 and 2012. The breaks for additive seasonal and trend (BFAST) method was applied to the smoothed time-series normalized difference vegetation index (NDVI), to detect the timing and magnitude of abrupt changes in the trend component. Large part of Poyang Lake (98.9% for trend component) has experienced abrupt changes in the past 13 years, and the change patterns, including the distributions in timing and magnitudes of major abrupt trend changes between water bodies and land areas were clearly differentiated. Most water bodies had abrupt increasing NDVI changes between 2010 and 2011, caused by the sequential severe flooding and drought in the two years. In contrast, large parts of the surrounding land areas had abrupt decreasing NDVI changes. Large decreasing changes occurred around 2003 at the city of Nanchang, which were driven by urbanization. These results revealed spatial–temporal land cover changing patterns and potential drivers in the wetland ecosystem of Poyang Lake.     

鄱阳湖区域夏冬季节沉积物面积变化分析研究

为更好地研究河流污染、河道阻塞、土壤沙化和湖泊面积锐减等问题,本文采用适宜的分析模型和高分辨率资源一号卫星影像,按照影像预处理、影像分类、矢量提取、特征分析的作业步骤,利用面向对象的遥感影像分类方法进行信息提取,针对夏冬两季的地物特征分别对鄱阳湖地区进行沉积物识别、地物类别判读以及湖泊的面积变化分析。研究表明:夏季鄱阳湖区域水体面积较大,泥沙较少,而冬季湖泊面积减少,泥沙等沉积物增多,并且存在相互影响的关系。     

三峡库区土地利用格局变化的分形结构研究——以开县为例

运用分形理论建立了研究区土地利用/覆被镶嵌体的分形结构模型,对各种景观的分维值进行了计算,讨论了各种景观形态的复杂性和稳定性及三峡工程实施十年间其稳定性和复杂性的动态变化。结果表明:分维值是研究区域土地利用/覆被镶嵌体景观格局的一种综合性定量指标,通过对土地利用景观类型的分维值进行分析,可以获取其形态的复杂性、稳定性信息。1992年和2002年两个时期研究区土地利用景观类型斑块形态复杂性和稳定性由大到小的顺序均依次为:未利用地、草地、建设用地、灌木林、森林、水田、旱地。十年间研究区旱地、建设用地和未利用地斑块形态变得愈加不规则,草地、灌木林、森林和水田的斑块形状变得愈加规则;十年间研究区旱地、建设用地和未利用地的形态稳定性变弱,草地、森林、灌木林和水田的形态稳定性增强。     

2001-2016年徐州市区土地利用类型时空演变

本文旨在定量分析徐州市区土地利用类型时空演变特征,为促进徐州市区绿色发展提供依据.以2001-2016年遥感图像为数据源,通过计算土地利用类型转移矩阵与动态度,对徐州市区土地利用类型时空演变进行分析.结果显示2001-2016年徐州市区耕地总体减少17.066 3 km2,减少面积占市区总面积的2.98％;建筑用地增加...     

清水河流域1978-2010年土地利用变化时空特征

通过对1978年、1998年和2010年3期遥感影像目视解译获得3期土地利用数据,分析清水河流域1978－2010年土地利用变化时空特征。研究表明：清水河流域1978－2010年期间,农用地、难利用地面积持续减少,林地、建设用地面积持续增加,草地面积先有所减少后增多,除林地以外其它土地类型变化幅度后期都较前期大;流域土地利用转移方向主要是农用地转为低、中、高覆盖度草地、林地和建设用地,中覆盖度草地转为低、高覆盖度草地和林地,低覆盖度草地转为中、高覆盖度草地、林地。结果表明,近年来清水河流域水土保持措施效果明显。     

基于GIS的岷江上游流域土地利用／覆被变化研究

以岷江上游流域为对象,选取3期9景TM/+ETM遥感影像,通过多步骤最大似然监督分类、变化检测,结合空间动态分析测算模型,分析近20年土地利用/覆被变化情况。结果表明:从整个流域分析,林地面积减少,主要转化为未利用地、建设用地和耕地;未利用地在前8年以每年3.7%、后8年以每年0.4%的速度增加;建设用地在1994—2002年以每年34%的速度增加,到2002—2010年增长速度减缓;耕地总面积减少54 431hm2;从县域分析,1994—2002年间,松潘和黑水县大面积林地转为未利用地;2002—2010年间,松潘县未利用地转为林地和建设用地,茂县和汶川县未利用地面积大幅增加。该研究结论不仅为国土资源管理部门优化土地利用结构提供依据,亦为当地政府实现生态资源可持续发展提供数据支撑。     

基于GIS的岳阳县土地利用变化研究

本文利用遥感和GIS技术,分析了岳阳县1993年～2002年土地利用变化及其空间分异特征。研究表明,9年间岳阳县农用地、水域呈减少趋势,建设用地、林地呈增加趋势,其中农用地的减少和林地的增加十分显著;主要转移方向包括农用地向建设用地、林地转移,水域向林地转移等;各类土地利用变化在空间上呈现明显的区域分异;城市化的迅速发展,旅游业的繁荣以及人类生态意识的提高是研究时段内土地利用变化的主要影响因子。     

结合高分遥感和多源数据的高原湖泊流域土地利用分析

高分一号卫星是为提升我国高分辨率数据自给率自主发射的卫星,在土地利用监测方面具有重要的应用价值。将GF-1卫星影像与多源数据影像进行对比能够挖掘各数据源在土地利用动态监测方面的差异性。本文以云南省杞麓湖流域为研究区,选取最新的Sentinel-2、GF-1和Landsat 8卫星遥感影像进行土地利用分类,以第二次全国土地利用调查数据为基期数据,结合野外实地调研和土地利用转移矩阵开展土地利用现状和演变分析,得出以下结论：①杞麓湖流域的水域、建设用地、耕地和林地自中心向外呈现出圈层分布的特征,与第二次全国土地调查结果相比,水域、耕地、林地3种类型的自然景观面积减少,而建设用地和其他用地受人类活动的影响,面积大幅增加,变化主要集中在杞麓湖周边的纳古镇和河西镇。②Sentinel-2卫星影像与GF-1卫星影像均具有较高的空间分辨率,二者对土地利用变化评估的结果相近,均优于Landsat 8卫星影像,其中GF-1卫星影像具有较高的应用价值。     

RS-and-GIS-supported forecast of grassland degradation in southwest Songnen plain by Markov model

By taking Daan city in Jilin Province as a research object and by using TM image in 1989 and ETM- image in 2001 from American LANDSAT satellite, all kinds of maps and documentation, information of grassland, saline-alkalized land, cropland, water area and forestland is extracted by man-computer interactive interpretation method with ArcView and Arclnfo GIS software, and statistics data is acquired. On the basis of this the changing trend of land use types in the next ten years is forecasted and analyzed with Markov model. The results indicate that the problem of grassland degradation in the study area is quite serious.     

太湖流域典型中小湖群水资源利用及动态变化的遥感调查与分析

近年来太湖流域中小型湖群的网围水产养殖业带来了十分可观的经济效益，挑、涌湖经遥感分析网围养殖面积占总湖水面积75％以上，属超密度网围。超密度网围养殖的负面效应是湖水营养盐急剧增高，水草资源大幅度减少，从而破坏了湖泊的生态平衡，恶化了湖水环境。采用15年以来的陆地卫星影像结合航空数据，对研究区的水资源利用类型、空间分布及变化状况进行了分析解译和目标分类，结合佃技术，对各类型进行了面积量算，推算了网围养殖密度，同时遥感分析了养殖水域环境和水草资源的变化，并展开了野外实地调查验证。     

石屏县土地更新调查的影像解译结果分析

利用2005年SPOT-5高分辨率卫星影像,运用RS、GIS、GPS等新的技术手段,分析、提取了石屏县土地利用变化信息。结果显示,石屏县新的土地控制面积为3 041.37km2,与2004年变更调查统相比较,现有辖区面积增加0.53km2。土地利用类型以农业用地为主,面积达25.40 536×104hm2,占总土地面积的83.53%。通过以高分辨率卫星影像进行更新调查,有效掌握石屏县土地利用状况和动态变化,查清土地利用结构,调整土地供应,有效利用土地资源提供了翔实的基础资料和科学依据。     

基于遥感的鄱阳湖丰水期悬浮泥沙数值模拟预测

悬浮泥沙是湖泊水体的重要水质要素之一,是湖泊水生态系统重要影响因子。利用遥感提取的鄱阳湖底质类型数据,对各类型底质区域上泥沙模型参数进行敏感性分析,基于2011年实测的不同底质区上泥沙浓度数据率定得到空间上不一致的泥沙模型参数,从而建立鄱阳湖丰水期二维悬浮泥沙输运模型。利用该模型模拟预测2013年丰水期悬浮泥沙输移过程,实测泥沙数据验证表明,模拟悬浮泥沙均方根误差为19.8 mg/L,相关系数R2为0.78,该模型能够较好地进行悬浮泥沙模拟预测。对比模型模拟和遥感反演的悬浮泥沙空间分布,两者具有较好的空间一致性,进一步表明该模型能够可靠地模拟预测鄱阳湖悬浮泥沙的时空动态变化。本研究充分利用遥感数据辅助建立鄱阳湖泥沙输移模型,为湖泊水环境动态变化监测提供有力的技术方法支撑,为进一步进行鄱阳湖水环境动态变化的数值模拟预测研究提供基础。     

Land use indicators of a watershed in arid region, western Rajasthan using Remote Sensing and GIS

The vegetation dynamics and land use/land cover types of Birantiya Kalan watershed located in the arid tracts of western Rajasthan have been characterized and evaluated using Remote Sensing and Geographical Information System (GIS). The watershed under study falls in the transitional plain of Luni Basin and is characterized by Aravali ranges in the eastern half and vast alluvial plains in the west. The land use/land cover types, as identified are cropland, fallow, forest, land with scrub, land without scrub, sandy area and the water body. Land with scrub occupied maximum area (39% area of the watershed) in 1996 in place of crop land which was dominant (43% of total area) in the year 1988. During eight years period, seasonal fallow land increased significantly and the areal extent of water body decreased to almost half. Vegetation vigour types have been classified into very poor, poor. moderate, good and very good categories. Moderate vigour type reduced from 62 to 27% and poor type increased from 34 to 68% during the period 1988 to 1996. Other vegetation vigour types have not shown any significant changes. To quantify the changes over the years in both vegetation and land use/land cover, weightages have been given to each type and composite values of both vegetation vigour and land use types for 1996 and 1988 have been calculated. It has been observed that the ratio for vegetation vigour has been found to be 0.85 showing that the overall vegetation have not improved after the treatment. The ratio for land use is found to be 1.01, which indicates negligible change in land use.     

基于遥感和GIS的南充市顺庆区LUCC动态变化分析

利用遥感、地理信息系统技术方法,精确解译顺庆区2000年与2007年两期Landsat-TM遥感影像,获得该地区土地利用/覆被的矢量图及定量统计数据,综合运用动态指标分析了LUCC特征。研究结果表明：该地区的耕地、林地和建设用地是LUCC的核心类型,三者面积之和超过研究区总面积的90%。7年间土地利用/覆被变化速度较快,耕地面积逐年减少,林地和建设用地面积显著增加,草地、水域则有少许减少。这些分析结果为查明该区土地利用及变化情况,揭示其中存在的问题,相关部门制定国土规划提供了科学依据。     

Changes in landuse/landcover patterns and human population growth in the Lake Chivero catchment,Zimbabwe

The land use and land cover pattern of a region is a consequence of natural and socio-economic factors and their utilization by man in time and space. In this study, we hypothesized that land use and land cover change patterns in the Lake Chivero catchment, Zimbabwe, were related to its human population dynamics. Using nonparametric correlation coefficients (Spearman’s rho, ρ), we found that bareland, cropland and built-up land had positive relations with human population growth of ρ = 0.7, ρ = 0.9 and ρ = 1, respectively. Grassland/shrubland, water and forest, on the other hand, had a negative relationship with human population growth of ρ = ?0.9, ρ = ?0.7 and ρ = ?0.667, respectively. However, these relationships were only significant (p < 0.05) for cropland, grassland/shrubland and built-up land. Human population dynamics in the Lake Chivero catchment could be one of the major drivers of land use and land cover change in the catchment between 1986 and 2014.