Measuring land-use and land-cover change using the U.S. department of agriculture’s cropland data layer: Cautions and recommendations

Monitoring agricultural land is important for understanding and managing food production, environmental conservation efforts, and climate change. The United States Department of Agriculture's Cropland Data Layer (CDL), an annual satellite imagery-derived land cover map, has been increasingly used for this application since complete coverage of the conterminous United States became available in 2008. However, the CDL is designed and produced with the intent of mapping annual land cover rather than tracking changes over time, and as a result certain precautions are needed in multi-year change analyses to minimize error and misapplication. We highlight scenarios that require special considerations, suggest solutions to key challenges, and propose a set of recommended good practices and general guidelines for CDL-based land change estimation. We also characterize a problematic issue of crop area underestimation bias within the CDL that needs to be accounted for and corrected when calculating changes to crop and cropland areas. When used appropriately and in conjunction with related information, the CDL is a valuable and effective tool for detecting diverse trends in agriculture. By explicitly discussing the methods and techniques for post-classification measurement of land-cover and land-use change using the CDL, we aim to further stimulate the discourse and continued development of suitable methodologies. Recommendations generated here are intended specifically for the CDL but may be broadly applicable to additional remotely-sensed land cover datasets including the National Land Cover Database (NLCD), Moderate Resolution Imaging Spectroradiometer (MODIS)-based land cover products, and other regional, national, and global land cover classification maps.     

国家环境遥感监测体系研究与实现

随着国家空间基础设施的建设和发展,中国遥感监测体系研究与建设取得了重大突破,从无到有形成了国家环境遥感监测能力,并业务化实现了主要环境遥感监测要素产品的生产与服务,为新时期环境管理工作提供了有力支撑。在分析国内外环境遥感发展及中国环境遥感监测需求的基础上,阐述了中国环境监测体系建设的必要性,研究了国家环境遥感监测体系的建立与业务化运行,提出了中国环境遥感监测体系发展思路与下一步重点任务。     

中国海洋卫星及应用进展

中国十分重视海洋遥感及其监测技术的发展,初步形成了具有优势互补的海洋遥感观测体系,并发挥了显著的经济和社会效益。其中,海洋一号(HY-1A/B)卫星已经广泛应用于中国海温预报业务系统、冬季海冰业务监测、夏季赤潮和绿潮监测、海岸带动态变化监测、近岸海水水质监测和渔业遥感监测等方面。海洋二号(HY-2A)卫星不仅填补了中国海洋动力环境卫星遥感的空白,也是目前国际上唯一在轨运行的集主被动微波遥感器于一身的综合型海洋动力环境卫星,具备同时获取风场、有效波高、海面高度和海面温度的能力。通过卫星获得的数据提高了中国海洋环境监测与灾害性海况预报的水平,为国民经济建设和国防建设、海洋科学研究、全球变化研究等提供了可靠的遥感数据,同时还在国际对地观测体系中发挥了重要作用,受到国内外用户的高度认可。海洋一号和海洋二号卫星系列为中国建立完善的海洋环境立体监测体系奠定了坚实基础。根据国家发展和"一带一路"建设的实施,在加快建设海洋强国、维护海洋权益和加快发展海洋经济的进程中对海洋遥感的发展也进一步提出了更高的要求和更紧迫的需求。为此,紧紧围绕国家海洋强国战略需求,在《国家民用空间基础设施中长期发展规划(2015年—2025年)》中专门规划了海洋观测卫星系列,服务于中国的海洋资源开发、环境保护、防灾减灾、权益维护、海域使用管理、海岛海岸带调查和极地大洋考察等方面,同时兼顾陆地和大气观测领域的需求。在充分继承已有HY-1A/B、HY-2A、高分三号(GF-3)和中法海洋卫星(CFOSAT)成功研制经验和应用成果的基础上,发展多种光学和微波遥感技术,建设新一代的海洋水色卫星和海洋动力环境卫星,具备卫星组网观测能力;发展海洋监视监测卫星,构建优势互补的海洋卫星综合观测体系。通过空间基础设施的建设,海洋遥感卫星必将在建设海洋强国的进程中发挥出重要作用。     

The Scientific Conceptual Framework for Ecological Quality of the Dryland Ecosystem: Concepts,Indicators, Monitoring and Assessment

The dryland ecosystem is the dominant component of the global terrestrial ecosystem since arid regions occupy 45% of the earth’s land area and feed 38% of the world's population. The stability and sustainable development of the dryland ecosystem are critical for achieving the millennium development goal (MDG) in the arid and semiarid areas. However, there is still no scientific guideline for measuring and conserving the health and productivity of dryland ecosystems. Therefore, the purpose of this study is to develop the scientific conceptual framework of defining, monitoring and evaluating the ecological quality of dryland ecosystems. The ecological quality of dryland ecosystems is represented by a system of comprehensive indicators that are each extracted from the ecological elements, and structural and functional indices of the ecosystem. These indicators can be monitored by integrating satellites and unmanned aerial vehicles with ground-based sensor networks at the scale of either observational sites or regional scales. Finally, the ecological quality can be evaluated by evaluation models based on the normalized index values and their thresholds. This paper presents a conceptual framework for monitoring and evaluating the ecological quality of drylands, which provides a way of advancing the monitoring, diagnosis, and evaluation of the ecological quality of the dryland ecosystems.     

近30a来长江源区沙漠化时空演变过程及成因分析

通过遥感与地理信息系统技术对1975-2005年长江源区沙漠化发展状况进行了监测,监测结果显示:长江源区有大面积的沙漠化土地分布,在这30 a问,沙漠化土地面积明显增加,尤其是极重度沙漠化土地的增加最为明显.长江源区不同程度的沙漠化土地总面积从1975年的31 118.3 km2增加到2005年的33 923.25 k...     

变形监测技术在基坑施工中的应用

深基坑工程是地下工程施工中内容比较丰富且富有变化的领域。为了确保基坑工程施工安全顺利进行,在复杂的地质条件下进行变形监测,及时发现和预报异常现象。对有效控制基坑变形、指导施工、保证施工质量具有重要意义。     

An asynchronous Geoprocessing Workflow and its application to an Antarctic ozone monitoring and mapping service

The integration of Sensor Web Enablement services with other Open Geospatial Consortium (OGC) Web Services as Geospatial Processing Workflows (GPW) is essential for future Sensor Web application scenarios. With the help of GPW technology, distributed and heterogeneous OGC Web Services can be organized and integrated as compound Web Service applications that can direct complicated earth observation tasks. Under the Sensor Web environment, asynchronous communications between Sensor Web Services are common. We have proposed an asynchronous GPW architecture for the integration of Sensor Web Services into a Web Service Business Process Execution Language workflow technology. We designed a Sensor Information Accessing and Processing workflow, an asynchronous GPW instance, to take an experiment of observing and mapping ozone over Antarctica. Based on our results, our proposed asynchronous workflow method shows the advantages of taking environmental monitoring and mapping tasks.     

PDCA循环法用于专业硕士产教融合培养模式研究

为满足新时代对卓越工程技术人才的需求,本文在分析专业硕士培养现状基础上,从人才培养方案入手,提出了PDCA理念用于产教深度融合培养模式,讨论了产教深度融合培养的目标制定、计划落实、课程体系开发、导师团队优化及实践基地的质量保障建设等方面的模式与对策,论述了专业硕士研究生培养的质量监控体系,总结出教育教学各环节的计划、执...     

SBAS技术在矿区地面沉降监测中的应用

本文采用小基线技术即SBAS-InSAR处理淮南市谢家集矿区的8景ALOS-PLASAR数据,时间跨度为2007年1月—2011年2月.首先利用SBAS-InSAR技术提取该矿区的时序形变速率,得到累计整体沉降趋势;然后针对公路、铁路、新旧矿区等重点沉降区域进行分析.由监测结果分析可知,十涧湖西路、堤坝整体处于下沉状态...     

TS50全站仪配合多测回测角软件在地铁基坑监测中的应用

TS50全站仪配合徕卡多测回测角软件能够自动瞄准、自动观测,具有高智能、高精度的特点,从而在地铁基坑监测领域得到广泛的应用.文章结合济南市轨道交通R1线前大彦站基坑监测项目实践,对测量方法、数据处理、监测效果等方面进行论述.实际应用表明:基于TS50全站仪的多测回测角软件能提供及时可靠的监测数据,科学指导基坑施工,保证...