黄河三角洲地区土地利用变化的梯度分析

目前土地利用研究是全球变化研究的前沿问题,虽然黄河三角洲土地利用变化分析在很多文章中都有提及,但都很少提到土地利用变化的梯度分析。本文选择黄河三角洲区域为研究对象,结合GIS技术、理论,对黄河三角洲海岸带地区进行了土地利用变化的梯度分析,为以后更好地开发和研究黄河三角洲土地提供了依据。结果表明:整个黄河三角洲地区耕地面积所占比例最大,越靠近沿海地区,耕地面积越小,未利用土地面积增大;反之,耕地面积越大,未利用土地面积减小。     

基于Landsat卫星的沈阳市土地覆盖变化研究

土地利用、土地覆盖变化(LUCC)是当今遥感领域的重要研究课题,也是地学界、生物学界、环境学界等关注的热点问题之一^[1]。特别是对大城市的土地类型变化研究,有利于揭示城市化进程中的空间变化规律。本文利用沈阳市1990、2000、2010年3期Landsat系列卫星数据,经过空间配准、相对辐射校正、图像增强等预处理,分别对3期遥感图像进行监督分类,提取土地类型转换信息并进行景观格局分析^[2]。结果表明,20年间沈阳市土地覆盖变化主要表现为耕地和建筑用地的转变,其中1990—2000年,耕地和建筑用地均有缓慢增加;而2000—2010年耕地面积明显减少,建筑用地显著增加,城市化进程大大加快。本文成果对沈阳市未来城市规划和可持续发展相关政策的制定有一定的参考价值。     

黄河三角洲建设用地与植被覆盖度时空变化及其相关性分析

为了研究黄河三角洲植被与建设用地的关系,利用1985—2010年的专题制图仪(Thematic Mapper,TM)影像,通过归一化植被指数(Normalized Difference Vegetation Index,NDVI)、增强的指数型建筑用地指数(Enhanced Index Building Land In...     

Investigating Grazing Intensity and Range Condition of Grasslands in Northeastern Kansas Using Landsat Thematic Mapper Data

Abstract

Grazing changes plant species composition of grassland ecosystems by selective removal and trampling. Grazing also alters soil physical and biogeochemical properties and can dramatically change hydrologic processes that can impact water budgets and quality. For these reasons, practical means are needed to assess grazing management practices and its impacts upon the land. This study examines whether a grazing intensity and range condition gradient can be detected in spectral reflectance characteristics of grasslands in northeastern Kansas. Multitemporal Landsat Thematic Mapper (TM) data, the normalized difference vegetation index (NDVI), and field data collected concurrent with the TM overpasses, were used in the analysis. Correlation analysis was used to examine relationships between spectral data and biophysical data. Next, the study sites within each grassland type were classified into three spectrally similar clusters. Grazing intensity, range condition, and biophysical characteristics were summarized for each spectral cluster and compared.

The results suggest that NDVI may be used as a surrogate for living biomass for both grassland types and may be useful for predicting grazing intensity in native warm season grasslands. And while there appeared to be relationships between total living and non‐living cover, and TM NIR and MIR bands, there were no direct relationships between spectral characteristics and grazing intensity or range condition.     

土地覆被变化对陆地碳循环的影响—以黄河三角洲河口地区为例

土地利用/土地覆被变化是全球变化研究的重点，是影响陆地碳循环的一个重要因子。该文对黄河三角洲河口地区1992年和1996年9月份的TM影像进行非监督分类，做出该地区土地覆被类型分布图，以及估算土地覆被类型的变化面积，计算结果显示1992年该研究地区植被碳库和土壤碳库分别为11.43×10     

基于GF-1影像的珍宝岛自然保护区土地覆盖变化分析

作为我国北方地区最具原始性和代表性的湿地,珍宝岛自然保护区于2008年被批准为国家级自然保护区。为研究珍宝岛自然保护区内土地覆盖和覆盖类型的变化情况,采用国产GF-1卫星数据,将遥感技术方法与野外调查法相结合,得到2014年和2016年的珍宝岛土地覆盖分类,并统计了各类地物的面积。通过对比两期数据,分析得到了土地覆盖类型的变化情况以及土地覆盖类型面积的转移情况。     

基于Landsat TM与CBER-02B的土地覆盖变化分析

以Landsat TM和CBERS-02B图像为遥感数据源,运用RS与GIS技术,对遥感数据的处理方法和技术流程进行系统的研究,并对汉寿县三期遥感影像进行处理,增强影像的可识别性。在野外调查和室内判别的基础上,建立研究区解译标志,采用机助目视解译方法,建立了1994年、2003年及2008年汉寿县土地覆盖数据库,提取并分析汉寿县土地覆盖变化信息。     

TM图像的光谱信息特征与最佳波段组合

本文分析了北自黑龙江省寒温带缓岗平原、南至广东省南亚热带丘陵等9个不同景观类型样区的TM图像数据,查明TM图像的光谱信息具3—4维结构,其物理含义相当于“亮度”、“绿度”和“热度”、“湿度”。在TM7个光谱图像中,一般以第5波段包含的地物信息最丰富。3个可见光波段(即第1,2,3波段)之间,两个中红外波段(即第5,7波段)之间相关性很高,表明这些波段的信息中有相当大的“重复性”或“冗余性”。第4,6波段则颇特殊,尤其是第4波段与各波段的相关性都很低,表明这个波段的信息有很大的独立性。计算20种组合的熵值的结果表明,由一个可见光波段、一个中红外波段及第4波段组合而成的彩色合成图像,一般具有最丰富的地物信息,其中又常以4,5,3或4,5,1波段的组合为最佳。     

综合主动和被动微波数据监测土壤水分变化

微波遥感测量土壤水分的方法主要分主动和被动两种，它们都是基于干燥土壤和水体之间介电常数的巨大差异。估算植被覆盖土壤表面土壤水分必须要考虑地表粗糙度和植被覆盖影响的问题。植被覆盖土壤表面的后向散射包括来自植被的体散射，来自地表的面散射和植被与地表间的交互作用散射项。本研究建立了一个半经验公式模型，用来计算体散射项，综合时间序列的主动和被动微波数据，消除植被覆盖的影响，估算地表土壤水分的变化状况。并应用1997年美国SGP‘97综合实验中的机载800m分辨辐射计ESTAR数据计算表面反射系数，综合Radarsat的SCAN-SAR数据得到体散射项，然后，由NOAA/AVHRR和TM计算得到的NDVI值加权分配50m分辨率的体散射项，最后计算50m分辨率的表面反射系数的变化值，从而得到土壤水分的变化情况，验证数据表明该计算结果与实测值一致。     

Using Advanced Land Imager (ALI) and Landsat Thematic Mapper (TM) for the Detection of the Invasive Shrub Lonicera maackii in Southwestern Ohio Forests

We tested how accurately image data from the Advanced Land Imager (ALI) sensor vs. the Landsat Thematic Mapper (TM) predict the land cover of Lonicera maackii in the forest understory, taking advantage of this invasive shrub's extended leaf retention in the fall when the canopy is leafless. Percent cover of L. maackii in 20 woodlots in southwestern Ohio was regressed on values for spectral vegetation indices (SVIs) derived for each image. The land cover of L. maackii was best explained by the Simple Ratio (SR) using TM data (R ² = 0.537). The regression results for SVIs from TM vs. ALI suggest that the ALI image was acquired too late in the fall to accurately detect this invasive shrub.     

基于Landsat遥感数据武汉地区植被覆盖度动态变化监测分析

旨在研究受人类经济活动影响的植被资源及其动态变化趋势的程度,采用基于归一化植被指数的像素二分模型,利用2002—2010年(武汉市每年8月)的卫星遥感数据,对武汉地区6年间的植被覆盖变化进行监测分析。结果表明,植被覆盖度变化与武汉GDP增长率有着紧密联系:2002—2007年,武汉经济较缓慢上升,植被覆盖度基本维持在55%左右;而2007—2008年武汉GDP总值增长率高达26.06%,但随之而来的是植被覆盖度由高峰期的61.68%下降到49.18%,是历年来的最低水准; 2008—2010年经济发展放缓,植被指数有小幅度回升。人类经济活动是影响植被资源的重要因素。     

应用MODIS数据对陕西地区土地利用/覆盖变化的监测

应用MODIS数据监测陕西地区土地利用/覆盖变化。主要内容是利用陕西省MODIS影像辅助以ETM＋等数据进行最大似然法监督分类,根据分类的结果得到各个土地利用类型面积,然后与统计资料对比,进行土地利用/土地覆盖动态监测分析。     

基于TM影像的北京城乡结合部土地利用变化分析

利用遥感分类技术能够快速获取土地利用变化信息。基于1996年和2006年两时相的北京城乡结合部地区TM卫星影像数据,采用监督分类和分类后处理方法,对研究区10年间的土地利用变化情况进行了详细分析,得到如下结论:10年间北京城南地区城乡结合部的各种土地利用类型之间相互转化,并以耕地,林地和建设用地相互转化最为显著;耕地和大范围水域面积较大幅度减少,城市居民点及工矿用地和未利用土地面积大幅度地增加,城乡结合部的范围在10年间从北向南进行了大范围地移动。     

Assessing Land Cover Change in Hydro-Climatic Data Network Watersheds Using NALC Imagery

Land cover conversion is known to alter the hydrologic regimes of watersheds. While connections between land cover and runoff are generally known, not all land cover alterations result in detectable changes in streamflow, and the quantity of land cover change required to yield a detectable change in streamflow is unknown over a range of watersheds. The connection between land cover change and streamflow was explored for a Hydro-Climatic Data Network (HCDN) watershed. HCDN is a database of USGS gauged streams commonly used to assess the influence of climatic change on streamflow. Watersheds included in the HCDN have been screened to represent "unimpaired" streamflow. Implicit in this definition is the assumption that land cover is relatively unaltered over the streamflow time series. Imagery from the North American Landscape Characterization (NALC) project was analyzed to detect land cover change from 1972 to 1992 in an Oregon watershed selected from the HCDN. A post-classification change detection yielded a 44% rate of landscape change over 20 years. Changes in land cover classes by dominant soil types were paired with the L-THIA model of Purdue University to quantify the effect of land cover change on runoff. Despite land cover changes, simulations confirmed that runoff remained unchanged. This report summarizes recommended steps for applying NALC imagery to detection of landscape change in other watersheds.     

SSM／I微波辐射计数据中国陆地覆盖特征季节变化分析

利用星载微波辐射计SSM／I多通道、多时相亮温数据开展了中国陆地覆盖特征的季节变化研究。通过对国内外星载微波辐射应用研究分析，提出了归一化极化指数(NDPI)的概念。处理了1997年4月、7月、10月和1998年1月的(每月的20、24日各两天)多通道SSM／I数据，在此基础上计算形成了第一幅中国陆地区域的归一化微波极化指数图，开展了中国陆地区域覆盖特征随季节变化的研究。研究结果表明，不同的陆地覆盖特征有特征的NDPI值，NDPI随季节而变化，植被、水分是引起NDPI变化的主要因子。     

Land Cover Change and Associated Trends in Surface Reflectivity and Vegetation Index in Southwest Kansas: 1972-1992

Abstract

Land cover is an important component of the earth system. Human induced surface alteration can affect earth systems directly, through loss or degradation of ecosystems, or indirectly through impact on the climate and biogeochemical cycles necessary to sustain life on earth. The significance of the earth's surface has made land use/land cover change an important issue in global change research. Alteration of land cover occurs at a variety of spatial scales, but as with many environmental change issues, the impacts of surface changes are often conceptualized at the global scale. In this study, we investigate the effects of land cover change on total reflected radiation and the Normalized Difference Vegetation Index (NDVI) in a 10,000 km² local area in the High Plains of southwestern Kansas. Landsat MSS data from five years of record within the twenty‐year period 1973 to 1992 were classified into cool season crop, warm season crop, and pasture/prairie. Mean values of summer reflectance and NDVI from each cover type and for the study area as a whole were then analyzed for systematic change over the study period. Both reflectivity and vegetation index increased during the study period, although causes for the increase appear to be different. Results suggest that changes in mean surface reflectance in the study site are strongly influenced by land cover change, whereas changes in NDVI are more closely linked to 50‐day antecedent precipitation.     

Mapping impervious surfaces with the integrated use of Landsat Thematic Mapper and radar data: A case study in an urban–rural landscape in the Brazilian Amazon

This research explored the integrated use of Landsat Thematic Mapper (TM) and radar (i.e., ALOS PALSAR L-band and RADARSAT-2 C-band) data for mapping impervious surface distribution to examine the roles of radar data with different spatial resolutions and wavelengths. The wavelet-merging technique was used to merge TM and radar data to generate a new dataset. A constrained least-squares solution was used to unmix TM multispectral data and multisensor fusion images to four fraction images (high-albedo, low-albedo, vegetation, and soil). The impervious surface image was then extracted from the high-albedo and low-albedo fraction images. QuickBird imagery was used to develop an impervious surface image for use as reference data to evaluate the results from TM and fusion images. This research indicated that increasing spatial resolution by multisensor fusion improved spatial patterns of impervious surface distribution, but cannot significantly improve the statistical area accuracy. This research also indicated that the fusion image with 10-m spatial resolution was suitable for mapping impervious surface spatial distribution, but TM multispectral image with 30 m was too coarse in a complex urban–rural landscape. On the other hand, this research showed that no significant difference in improving impervious surface mapping performance by using either PALSAR L-band or RADARSAT C-band data with the same spatial resolution when they were used for multi-sensor fusion with the wavelet-based method.     

基于地理国情普查数据的昌江县沿海地表覆盖变化监测

阐述了基于地理国情普查数据与多时相航天遥感影像资料,对昌江县沿海地表覆盖变化进行监测,形成自1996年至今近20年昌江县沿海地表覆盖变化监测成果。同时,针对不同时期地表变化情况进行统计,分析了地表覆盖构成与转移,形成系列数据、图件、报告等成果,为建设管理沿海林地、保护沿海地带生态环境、合理利用开发海岸线等提供科学的决策依据。     

基于遥感数据的哈尔滨土地利用/覆被变化研究

以哈尔滨市为例,基于Landsat数据,利用遥感技术和GIS技术对2000和2015年的遥感影像数据进行解译分类,通过对分类结果的统计分析,定量研究哈尔滨市15年间的土地利用变化过程,结果显示:哈尔滨市土地综合利用程度较高,区域内耕地面积减少;相反,城市建成区面积大幅增加,区域内绿地面积逐年减少,应注意生态环境维护保持。     

黄河三角洲典型地区土地利用变化遥感监测及驱动力分析

黄河三角洲是我国重要的后备土地资源开发利用区,是土地利用、覆被变化研究的热点区域。本文选择黄河三角洲核心区域垦利县为研究区,采用2001、2005、2011和2014年的卫星遥感数据,基于RS和GIS技术,在ENVI软件支持下,利用监督分类方法,提取了研究区各时相土地利用类型面积及分布信息,研究了该区土地利用时空变化特征与规律,并结合研究时段内的自然和社会经济因素,对研究区土地利用变化驱动力进行了分析。研究结果表明:耕地、盐荒地和滩涂是该区土地利用的主要类型;研究时段内,垦利县土地利用发生了显著变化,陆地面积总体增加,耕地、林草地呈现减少趋势。耕地是减少速度最快、减少面积最大的土地利用类型,建设用地、盐荒地、滩涂则处于持续增长状态。气候水文因素是主要的自然驱动力,而人类的开发建设活动是主要人为驱动力。研究结果对于该区的土地资源合理利用及经济社会可持续发展具有积极意义。