基于多时相中巴资源卫星影像的冬小麦分类精度

中巴资源卫星2号星（CBERS-02）具有较高的空间分辨率和较丰富的光谱信息,对植被有较强的探测能力.利用2006—2007年北京地区冬小麦生育期早期的5景CBERS-02卫星影像,计算了各时相和不同时相组合的主要地物类型及冬小麦的光谱可分性距离,进行了监督分类,同时,结合高分辨率航空和卫星遥感影像,构建了训练样本和验证样本,对利用CBERS-02卫星提取的生育早期的冬小麦进行了时相分析和精度评价,并与同期TM影像提取结果进行对比.结果表明：时相是影响冬小麦分类的主要因素,不同光学传感器的遥感影像也会影响分类精度;多时相组合有利于提高冬小麦的提取精度,与单时相冬小麦提取的最高精度相比,最佳时相组合的制图精度提高了20.0%、用户精度提高了7.83%;与TM数据相比, CBERS-02卫星影像的冬小麦分类精度略低.     

环境减灾卫星多光谱CCD影像自动几何精纠正与正射校正系统

我国环境减灾光学卫星(HJ)多光谱CCD影像由于具有高时空分辨率、大幅宽等优势,能够提供同一区域不同生长阶段的植被信息,是提取具有生态学意义土地覆盖及开展植被生理生态参量反演的重要数据源之一。然而,目前该数据产品的几何定位不准确及山区地形畸变误差使其难以满足应用需求。高定位精度是遥感影像信息提取、参数反演与应用分析的前提,遥感影像的几何精纠正与正射校正是遥感数据预处理面临的首要问题。在分析国内外卫星影像自动化处理系统研究现状的基础上,结合HJ CCD影像幅宽大的特点,构建了HJ CCD影像的自动几何精纠正与正射校正处理系统。与目前商业软件相比,自动几何精纠正与正射校正处理系统采用了自动化的控制点搜索与过滤方法,能有效提高控制点选取的效率与精度。同时,结合DEM数据,系统自动拟合卫星飞行路径并纠正由偏离星下观测导致的山体位移。系统应用结果表明,自动几何精纠正和正射校正系统能够有效的提高处理效率,节省人力和时间成本。该系统已被成功应用于全国生态十年(2000—2010年)变化遥感调查与评估专项土地覆盖遥感监测的环境减灾卫星多光谱遥感影像预处理工作。     

莱州湾南岸滨海湿地的景观格局变化及累积环境效应

在湿地景观类型分类基础上,利用遥感技术及GIS技术提取了1987和2002年莱州湾南岸滨海湿地Landsat 5、Landsat 7 卫星假彩色合成影像的空间属性数据,利用斑块动态度、斑块密度指数、景观多样性指数、斑块破碎化指数研究了湿地景观格局变化及其累积环境效应.结果表明,15年间莱州湾南岸滨海湿地景观总面积基本不变,但自然湿地总面积减少了49.1%,减少的自然湿地主要转化为养殖池、盐田等人工湿地.湿地景观格局的变化还表现为景观多样性指数下降、斑块破碎化指数升高.湿地景观格局变化引起自然湿地的总净初级生产量下降,环境净化功能、抗御自然灾害功能降低,陆地中生植物、旱生植物外来及有害植物侵入湿地,湿地生态系统服务价值下降等累积环境效应.     

1995—1999年黄河三角洲东部自然保护区湿地景观格局变化

基于1995和1999年的Landsat TM遥感影像,结合地理信息系统技术,分析黄河改道清8汊（1996年）前后的1995—1999年黄河三角洲东部自然保护区（位于黄河现行流路入海口处）湿地景观格局的变化特征,以及影响湿地景观格局变化的驱动因素.结果表明：1995—1999年,保护区湿地仍以天然湿地为主,人工湿地比重极小,期间非湿地面积大幅增加,而天然湿地和人工湿地面积则呈下降趋势,其中,裸露淤泥质滩涂和沼泽湿地面积明显萎缩;尽管保护区湿地景观类型、形状、结构的变化程度不均一,且各景观类型在空间分布上的团聚程度变化不均衡,但总的看来,保护区景观整体结构趋于复杂化,破碎化程度有所加深,内部各景观类型从大块连续的镶嵌分布向小块离散分布转变;影响保护区湿地景观格局变化的主要因素有3个：黄河改道、黄河断流和人类活动.     

基于中分辨率TM数据的湿地水生植被提取

利用湿地水生植被生长旺盛、光谱反射较强、光谱信息比较丰富的8月份中分辨率Landsat TM和ETM+多光谱遥感影像,采用面向对象的分类方法,进行野鸭湖湿地水生植被的提取。研究表明:在提取过程中,通过对原始影像进行主成分变换和穗帽变换,将主要信息与噪声分离,不仅减小了数据冗余和波段间的相关性,而且增大了影像上湿地水生植被与其他地物类型光谱和空间信息的差异性,并结合野外水生植被光谱特征分析,选择归一化植被指数NDVI与归一化水体指数NDWI辅助分类,构建特征波段或波段组合,然后,确定适当的隶属度函数和阈值范围,构建分类决策树,完成湿地水生植被的自动分类,提高了影像分割与面向对象分类的精度,取得了较为理想的湿地水生植被提取结果。2002年和2008年两景影像的总体分类精度分别达到86.5%和85.44%,表明中分辨率TM影像可以满足湿地水生植被提取的需要,又因为其具有较高的波谱分辨率、极为丰富的信息量、相对较低的价格、长时间序列,可以作为近20a湿地水生植被提取和动态变化监测的主要数据源。     

基于阈值法的山区森林常绿、落叶特征遥感自动识别方法——以贡嘎山地区为例

森林的常绿、落叶特征是土地覆被产品的重要属性。由于山区地形复杂,地表遥感辐射信号地形效应明显,导致山区森林常绿、落叶特征遥感自动识别一直是难点。提出了一种基于阈值法的山区森林常绿、落叶特征遥感自动识别简单实用方法。该方法利用多源、多时相遥感影像,选择归一化植被指数(NDVI)为指标,通过统计参考样本的NDVI在生长季和非生长季的差异,自动找出区分常绿、落叶特征的阈值,基于判别规则识别山区森林常绿、落叶特征。以贡嘎山地区为例,分别以多时相Landsat TM影像(简称TM)、多时相环境减灾卫星影像(简称HJ)为单源数据,多时相的HJ、TM组合影像为多源数据,验证该方法的有效性。实验结果表明,该方法能够有效识别山区森林常绿、落叶特征,总体精度达到93.87%,Kappa系数为0.87。该方法适用于山区大面积森林常绿、落叶特征遥感自动提取,已被成功应用于"生态十年"专项西南地区土地覆被数据的生产。     

厦门湾海岸带景观格局时空动态演变研究

以厦门湾海岸带为研究区, 基于1989 年与1997 年Landsat TM、2010 年SPOT5 遥感影像, 在遥感和GIS 技术支持下, 建立了厦门湾海岸带景观类型空间数据库。运用景观类型变化表征模型与景观格局指数方法, 对近22 年来研究区景观格局变化时空动态特征进行了定量分析。研究结果表明: 厦门湾海岸带景观格局发生了较大的变化。农用地面积持续减少且降幅最显著, 而城镇用地与建设用地则快速扩展; 其中前者由占总面积的72.75%下降到30.67%,后者由占总面积的4.60%上升到38.97%。土地利用类型之间、以及各土地利用类型与滨海湿地之间的动态转化频繁,土地利用类型之间的转化以农用地和滨海湿地向城镇用地与建设用地转化为主。在1989-1997 年农用地净转出面积为13862.55 hm2, 滨海湿地转出面积为4268.82 hm2; 在1997-2010 年农用地转出达到20910.24 hm2, 典型滨海则转出 5931.64 hm2。在景观水平尺度上, 景观格局向着多样化方向发展, 景观的异质性增强, 景观破碎化程度加深。景观格局变化的驱动因素主要为社会经济发展与政策调整。     

云贵高原国际重要湿地景观人为胁迫遥感解析

以云贵高原4处国际重要湿地为研究对象,以1977—2015年5期Landsat系列卫星遥感影像为遥感数据源,基于面向对象的方法获取多期土地覆盖数据,分析研究区湿地面积变化;应用景观指数、动态度、人为直接干扰度3个参数,探讨云贵高原国际重要湿地人为胁迫对湿地景观变化的影响及湿地保护成效。结果表明:38年间云贵高原的4处国际重要湿地范围内的湿地面积共损失7.6%,约299 hm2,人为直接占用是湿地损失的主要原因;人为直接干扰度从1977年的7.4%增长到2015年的13.5%; 38年间湿地景观破碎度上升,斑块增多,聚集度下降,蔓延度下降,景观破碎化明显; 4处国际重要湿地景观变化差异性明显,拉市海与大山包景观变化较大,受人为胁迫相对明显;碧塔海与纳帕海景观变化较小,保护效果相对较好。该研究结果可为高原湿地的保护和可持续管理提供科学依据。     

基于QUEST决策树兼容多源数据的淡水沼泽湿地信息提取

以三江平原东北部为例,探讨了中国典型淡水沼泽湿地信息的提取方法.利用TM卫星影像数据,基于半方差分析和z检验方法对比研究区典型地物不同尺度的各种纹理特征,从而遴选最优的窗口大小、纹理特征及其派生波段以提高地物之间的可分性.采用快速、无偏、高效统计树(quick,unbiased,and efficient statistical tree,QUEST)算法集成遥感影像的光谱特征、多尺度纹理特征和地学辅助数据建立研究区湿地信息提取的决策树模型.基于实测的GPS样本点采用混淆矩阵的方法对分类结果进行精度验证,并与传统的最大似然监督分类方法(maximum likelihood classification,MLC)进行对比.结果表明,基于QUEST的决策树分类结果的总精度和Kappa系数分别为84.58%和0.816,分类精度较MLC监督分类方法有明显提高,是内陆淡水沼泽湿地信息提取的有效手段.     

浙江西门岛湿地景观格局与人为干扰度动态变化

基于西门岛湿地2007和 2010年两期SPOT 5影像(空间分辨率均为5 m)数据,结合西门岛湿地土地利用现状,参考《全国土地利用分类》（试行）、海域使用分类海洋行业标准以及综合考虑遥感数据特性,建立西门岛湿地人为干扰类型分类系统;应用景观格局指数法、GIS空间分析法,得到景观指数和人为干扰度指数,探讨了西门岛湿地景观格局与人为干扰度动态变化.结果表明: 研究期间,西门岛湿地景观异质性、破碎度和优势度降低,景观形状复杂度降低.西门岛湿地人为干扰中心由分散发展到集中;干扰中心主要贡献景观类型是裸地和居民点;干扰总程度由海域向陆地逐渐加重,居民点、码头、交通用地干扰总程度最高.滩涂养殖、泥滩地、浮筏养殖景观的人为干扰度跳跃性大.水陆交错带出现干扰总程度较低但干扰极不平稳的现象.无干扰、半干扰和全干扰型景观的斑块数量下降.无干扰、半干扰景观的平均斑块面积增加,全干扰景观的平均斑块面积减少.无干扰景观的平均形状指数下降,半干扰型和全干扰型景观形状有复杂化趋势.     

Satellite remote sensing of wetlands

To conserve and manage wetland resources, it is important to inventoryand monitor wetlands and their adjacent uplands. Satellite remote sensing hasseveral advantages for monitoring wetland resources, especially for largegeographic areas. This review summarizes the literature on satellite remotesensing of wetlands, including what classification techniques were mostsuccessful in identifying wetlands and separating them from other land covertypes. All types of wetlands have been studied with satellite remote sensing.Landsat MSS, Landsat TM, and SPOT are the major satellite systems that have beenused to study wetlands; other systems are NOAA AVHRR, IRS-1B LISS-II and radarsystems, including JERS-1, ERS-1 and RADARSAT. Early work with satellite imageryused visual interpretation for classification. The most commonly used computerclassification method to map wetlands is unsupervised classification orclustering. Maximum likelihood is the most common supervised classificationmethod. Wetland classification is difficult because of spectral confusion withother landcover classes and among different types of wetlands. However,multi-temporal data usually improves the classification of wetlands, as doesancillary data such as soil data, elevation or topography data. Classifiedsatellite imagery and maps derived from aerial photography have been comparedwith the conclusion that they offer different but complimentary information.Change detection studies have taken advantage of the repeat coverage andarchival data available with satellite remote sensing. Detailed wetland maps canbe updated using satellite imagery. Given the spatial resolution of satelliteremote sensing systems, fuzzy classification, subpixel classification, spectralmixture analysis, and mixtures estimation may provide more detailed informationon wetlands. A layered, hybrid or rule-based approach may give better resultsthan more traditional methods. The combination of radar and optical data providethe most promise for improving wetland classification.     

基于遥感的湿地景观格局季相分析

以中国东北地区三江平原北部为研究区域,利用2012年多季相遥感影像作为数据源,结合野外调查数据,应用面向对象的分类方法,根据影像的物候、时相等特征,提取不同月份的湿地信息,进行景观格局季相分析。结果表明:(1)研究区湿地面积、类型格局在同一年不同季节不同月份会有不同幅度的变化,总体呈现缓增骤减的态势。湿地主要分布在低洼地区,主要湿地类型为草本沼泽,其次为河流,其他湿地占总面积比例较小。(2)研究区各阶段湿地都有转化,主要发生在湿地和非湿地之间,多数表现在草本沼泽和草地之间的转化。(3)湿地分布和湿地转化面积主要集中在低海拔区域和低坡度区域,其中海拔100 m和坡度5°以下范围内的湿地分布面积和湿地转化面积占湿地总面积及湿地转化面积的绝大部分。(4)年内季节性湿地转化与降水、温度和湿地植被物候关系密切。     

红树林生态系统遥感监测研究进展

随着现代遥感技术的迅速发展,遥感监测已经成为红树林生态系统变化监测的重要手段和方法。从遥感技术在生态系统变化监测应用领域入手,综述了国内外红树林遥感监测的发展历程,系统总结了遥感技术在红树林湿地动态、种间分类、群落结构(叶面积指数、冠幅、树高等)、生物量、灾害灾情(病虫害、风暴潮等)、景观格局动态、驱动力、红树林湿地保护与管理等领域应用现状,归纳了不同应用领域遥感监测的理论、方法及研究现状。指出我国在红树林遥感监测中存在的不足。提出红树林遥感监测应在分类标准体系规范化、分类精度提升、红树林生态学特征参数(物种多样性、优势度等)、生态系统环境空间演变过程及遥感监测的尺度效应方面加大研究力度。充分发挥区域综合监测模型在红树林生态系统变化遥感监测中的作用。     

无人机在生物多样性遥感监测中的应用现状与展望

近十年, 无人机平台由于其灵活机动、成本低等优势在植被生态调查、资源环境监测、生物多样性保护等领域逐渐兴起。本文从生物多样性遥感监测应用角度首先介绍了无人机分类系统, 为具体工作开展过程中如何选择合适的载体和传感器提供了参考; 继而总结了不同类型无人机的适用性及其可搭载传感器的用途与区别。在此基础上, 针对无人机平台的高精度遥感信息具体应用案例, 就反映生物多样性变化并揭示其驱动机制方面的无人机遥感直接和间接指标的相关研究进展展开阐述。最后, 就目前无人机遥感技术在生物多样性监测领域的应用中存在的限制, 如软硬件结合匹配程度不够、部分设备过于昂贵、法律法规不完善、与传统生物多样性监测手段结合较弱等问题进行探讨。我们认为: 无人机遥感技术可以很好地弥补地面监测与航天、卫星遥感之间的尺度空缺, 更好地将监测点上的结果以准确、可靠的推绎方法扩展到区域尺度供决策分析使用。今后迫切需要进一步加大生物多样性近地面遥感监测项目建设的实施力度, 从整体上提高生物多样性热点区域应对变化的分析预警能力。     

The missing wetlands: using local ecological knowledge to find cryptic ecosystems

Small, temporally dynamic, biologically diverse isolated wetlands are among the most imperiled ecosystems, yet their conservation is hindered by lack of protective legislation and mapping. As part of an effort to better understand isolated wetland ecology in an area undergoing dramatic land use change, we mapped isolated wetlands in South Carolina’s Piedmont and Blue Ridge regions using remote sensing and local ecological knowledge (LEK). Remote detection of isolated wetlands was limited by digital resource resolution, topography, and wetland size. LEK was the most useful tool for locating small isolated wetlands. We sampled 10% of the study area using LEK and discovered 44 wetlands with “isolated” characteristics, none of which had been identified by remote sensing. Only 8 of 44 wetlands found through LEK could be identified using remote sensing after their discovery. LEK fills a gap in cryptic ecosystem detection when adequate remotely sensed data are not available. Though effective, using LEK is neither as rapid nor as repeatable as remote sensing. We suggest a two-pronged approach for finding cryptic ecosystems: remote sensing coupled with LEK where data resolution is inadequate. For remote detection of isolated wetlands, we suggest a minimum resolution of 0.33 m for Color Infrared, leaf-off, high-water photography. Despite great advances in remote sensing, data are not uniformly available worldwide and LEK may serve as an effective tool for locating cryptic resources for biodiversity conservation. Mapping cryptic resources will allow for more accurate resource and biodiversity conservation planning under current and future climate scenarios.     

基于多源遥感数据的生态保护修复项目区监测方法评述

回顾了山水林田湖草生态保护修复项目的实施背景,针对生态保护修复项目监测监管范围广、技术难等问题,强调了基于多源遥感数据开展项目遥感监测的重要性与必要性。从监测指标拟定、遥感地物信息提取、多源遥感数据融合、动态变化检测等方面评述了基于多源遥感数据的生态保护修复项目区监测方法,包括基于中高空间分辨率遥感数据的地物信息提取、融合机器学习的非线性混合像元分析、基于混合像元分析的时空融合等。在总结技术和工作推进方面的优势、局限基础上,提出要结合实际工作,持续优化国土空间生态保护修复监测指标;充分挖掘遥感数据解析的相关算法潜力,提升地物信息提取和混合像元分析的精度;加强时空融合算法与变化检测方法的研究探索,加强相关方法的实践应用;以“山水林田湖草生态保护修复工程试点”项目为平台,建立稳定的国土空间生态保护修复遥感监测运行机制,加强科技创新,形成技术标准,指导工作开展。     

Combined application of remote sensing and in situ measurements in monitoring environmental processes

Combined use of remote sensing in the visible, infrared and microwave spectral regions, direct in situ measurements and model numerical experiments makes it possible to study inland water bodies as elements of water body-catchment-atmosphere-systems with good spatial and temporal resolution. In this paper examples are presented of the remote sensing methods developed for detection of hydrodynamics of large water bodies (e.g. frontal and upwelling zones, internal waves, warm and cold surface layers), monitoring of chlorophyll concentration, suspended minerals and dissolved organic matter (DOM) in lakes, mapping of shallow water zones, wetlands and landscape structures, monitoring of ecological condition and changes of drainage basins, and studying the state of the atmosphere over lakes and catchment areas.     

Use of aerial imagery to assess habitat suitability and predict site occupancy for a declining wetland-dependent bird

Remote sensing is a valuable tool for wetland habitat quantification, monitoring and assessment. Here we show that habitat assessment via aerial image inspection is useful in predicting wetland site occupancy by black terns (Chlidonias niger), an imperiled and declining species throughout much of North America. We used Google Earth^® images and National Wetlands Inventory maps to rank 390 candidate wetlands throughout Wisconsin (USA) according to their apparent suitability as nesting habitat for black terns and quantified habitat features associated with the suitability rankings. We then conducted ground-based suitability assessments and point counts of terns at most wetlands from May to July 2010. Pre-survey assessment resulted in 123 wetlands classified as suitable, 81 as marginal, and 186 as unsuitable. Wetlands ranked as suitable were more likely to be in the hemi-marsh stage, part of a wetland complex and relatively undisturbed. Black terns were present at 47 % of the wetlands considered suitable but only 11 % of the sites considered marginal or unsuitable. Of the 42 sites where nesting was confirmed, 79 % were at wetlands classified as suitable; no nesting was recorded in any wetlands deemed unsuitable. We found strong concordance in wetland suitability rankings between the two assessment methods (remote sensing, site surveys). We propose that remote sensing is an efficient and inexpensive way to predict site occupancy by wetland birds, such as black terns, that prefer a specific kind of habitat discernible from aerial imagery. This method may be particularly useful in areas, such as the Prairie Pothole region of North America, where ground surveys of all wetlands are not feasible.     

Long-term monitoring of wetlands along the Western-Greek Bird Migration Route using Landsat and ASTER satellite images: Amvrakikos Gulf (Greece)

The west coast of Greece is an important migration route for migratory waterbirds. The wetlands along this coast are important stopover sites during bird migration between wintering and breeding sites. The use of remote sensing methods for mapping bird migration habitats and for temporal monitoring of changes in these habitats was investigated. The Amvrakikos Gulf, a coastal wetland complex along the west coast of Greece, was selected as the study area. Landsat TM and ETM+ images and ASTER VNIR images were used to perform a post-classification change detection over a time period of 15 years (1989–2004). In order to assess the spatial quality of existing wetland patches, spatial metrics (such as patch area, distance between the patches, and proximity) were calculated. To study changes in the degree of fragmentation of the stopover area, a binary patch structure was used in which the focal patches were embedded in a neutral matrix. The results showed that Landsat and ASTER VNIR satellite images can be used to trace small wetlands of approximately 0.5 ha minimum. These data sources are suitable for monitoring changes in wetlands, in particular marshes and mudflats, which are important habitats for migratory waterbirds. In the 15-year period that has been studied there was an estimated 32% decrease in marsh and mudflat area. Among this decrease, 25% went to water surface and 7% to vegetation in the months of August and September. Within the same period of time, a higher degree of fragmentation of the potential bird migration habitat has also been recorded. For this purpose, the remote sensing approach used in this study where change detection is performed on freely available Landsat and ASTER satellite images could be an interesting tool for policy makers and managers, as they allow easy recognition and monitoring of changes in wetlands and therefore contribute to an evaluation of the efficiency of protection and management schemes applied by countries for their wetlands.     

利用遥感光谱法进行农田土壤水分遥感动态监测

自 1 997年 4月至 1 998年 1 0月 ,在甘肃省定西县进行了大面积 0～ 5 0 cm土层农田土壤水分按每 1 5 d本底资料实际观测 ,对此间收到的 5幅 TM与 7幅 NOAA卫片数据资料进行了加工处理 ,并对地面光谱资料也进行了观测。在光谱反演与光谱和土壤水分相关性分析基础上 ,利用遥感技术和地理信息系统 ,初步建立了典型试验区 ( 3× 3km2 )遥感信息与土壤含水量之间的遥感光谱相关监测模型 ,做出了观测区土壤水分含量分布图和得到了大面积农田土壤水分宏观动态监测结果 ,并同地面实测土壤水分进行了精度校正。研究结果表明 ,文中提出的“光学植被盖度”概念 ,对土壤水分遥感监测研究是有益的 ,利用遥感光谱法和数学统计方法求出了有关物理参数 ,初步建立了 TM与 NOAA光谱水分监测模型 ,其模型监测 0～2 0 cm土层含水量的精度达到 90 %以上 ,实际监测土壤水分精度达到 72 .3% ;在遥感监测 2 0～ 5 0 cm土层土壤含水量中 ,利用遥感模型监测土壤水分精度达到 80 %以上 ,实际遥感监测精度达到 60 %左右 ,其结果可有效指导干旱半干旱雨养农业区春耕时间和动态监测大面积土壤墒情 ,可为农业生产提供科学依据。另外 ,经地面大量观测表明 ,一般来说 ,当土壤含水量为田间最大持水量的 5 5 %～ 85 %时 ,从生长状况和经济