建设全球碳循环一体化观测的协调体系——基础、条件、任务与目标

全球碳循环的观测进入综合集成观测时期,建立全球一体化观测的协调体系极为必要。以IGOS的全球一体化碳观测主题项目(IGCO)框架为基础,分析了建立全球碳循环一体化观测体系的现有基础、制度和条件需求,提出了这一体系建设目标和观测任务,其未来观测任务:碳库的规模和变化、通量的大小和分配以及碳循环的过程等主要观测内容。     

冻融过程与陆地生态系统碳循环的相互关系研究进展

全球变化与可持续发展研究是当今地学研究的两大主题,陆地生态系统碳循环对全球变化影响重大。冻土中的碳储量占据全球陆地碳储量的重要份额,它对气候变化十分敏感,是气候变化的指示器,研究冻土地区土壤的冻融过程及其与陆地生态系统碳循环之间的相互关系对于全球变化研究具有重要意义。在总结冻融对碳循环过程影响机理的基础上,回顾了国内外关于冻融影响下碳循环模拟研究的主要进展,指出了其存在的主要问题,并对未来冻融与碳循环研究发展趋势做了初步的展望。     

高校专业“教、赛、研”立体大数据互通教学模式研究

当前,全球已经进入信息化时代,大数据在信息传播、共享等相关领域已经广泛应用。许多高校的教学模式也要在此趋势下进行更新优化。本文旨在阐明高校专业结合大数据信息资源,应用“教、赛、研”模式存在的问题、优势以及具体策略等,对于高校专业后续发展具有积极意义。     

地球观测与导航技术领域参加“十一五”重大科技成就展获得圆满成功

为全面总结"十一五"时期取得的重大科技成就,大力弘扬自主创新精神,由科学技术部、中共中央组织部、国家发展和改革委员会、财政部等十家单位主办的"十一五"国家重大科技成就展于2011年3月8日至14日在北京国家会议中心举行。本次展览全面介绍了"十一五"期间我国科技战线取得的重大科技成就,地     

互联网改变社会与生活——中国社会科学院社会发展中心“全球互联网项目”2005报告（节选）

对显联网的看法和态度 在2003年的调查中，社科院互联网调查通过对网民和非网民的对互联网的不同看法和态度进行分析，得出了对网络的消极态度影响了普通民众对互联网的使用的结论。两年过去了，有必要再次检验人们对网络的印象是否有变化。     

Analysis of the Development Trend of Global Papers Combining the DMSP-OLS Nighttime Light Data

The multi\|subject cooperation and intersection becomes the main development tendency of the modern sciences.In this study,the remote sensed nighttime light data from the Defense Meteorological Satellite Program(DMSP)Operational Linescan System(OLS)were combined with the global international papers for obtaining the temporal and spatial distribution characteristics and dynamic change characteristics at national and regional scale.The results indicate that most of the countries or regions have the increasing tendencies with the exponential models.There are good correlation between the nighttime light data and international paper for most of the countries or regions.In the 72 calculated countries,there are 53 countries with the correlation coefficients more than 0.5 when the significance level is more than 0.01.Furthermore,the developing countries have higher correlation coefficients than the developed countries.In the top 18 countries with higher correlation coefficients,16 are the developing countries.The night\|time light data can be potentially used to better predict the numbers of countries’ papers.     

若尔盖高原区域碳收支参量多尺度遥感综合观测试验:科学目标与试验设计

介绍了若尔盖高原区域碳收支参量多尺度遥感综合观测试验的研究背景、科学目标、关键问题、观测方案、观测系统设置和后续观测计划.总体目标是,开展若尔盖高原区域湿地-草地生态系统碳收支参量多尺度遥感与地面同步观测试验,为人为干扰条件下湿地-草地生态系统碳收支变化过程研究积累基础数据;发展能够融合多源、多尺度遥感观测的碳收支相关参量反演模型,为实现卫星遥感对区域尺度碳收支研究提供方法和范例;建立区域尺度上的多尺度观测体系,通过多源遥感技术与生态过程模型的耦合,降低碳收支遥感监测及模拟的不确定性,更加综合地理解湿地-草地生态系统不同时空尺度上的碳收支过程;增强遥感技术在湿地生态研究的应用性,并最终为区域湿地保护提供重要依据.试验以人为干扰剧烈的若尔盖高原湿地-草地区域为试验区,以碳循环过程的关键参量为主要观测对象,利用卫星遥感、航空遥感、地基遥感、通量观测、生态观测等相关设备,开展航空、卫星和地面配合的大型综合观测试验,精细化观测若尔盖高原沼泽化草甸、湿草甸、草甸、草原等不同覆被类型的碳收支过程的各个分量.讨论了碳收支参量的多尺度观测与时空尺度扩展问题,展望了同步综合观测试验在陆地生态系统碳循环研究的应用前景.     

Urbanization pressure and modeling of urban growth: example of the Tunis Metropolitan Area

Urbanization process is a major factor of change in the Mediterranean region where pre-urban cities and new urban settlements have raised over the past decades. Several cities rapidly became regional centres or international nodes according to economic and political pressures. Urbanization (and informal settlement) causes land cover changes which can lead to deeper social, economic and environmental changes. The main objective of this paper is to provide time-series information to define and locate the evolution trends of the Tunis Metropolitan Area. In a first step, satellite imagery has been used (1986-1996 SPOT XS) to extract the land cover, identify the urbanization processes and estimate the changes. One of the main aspects is to locate informal settlement areas that grow significantly along the roadway networks in the Tunisian capital. Results show a global progression of the built-up areas of 13% in 10 years. In a second step, the urban growth evolution has been approached by using a potential model that provides general trends of feasible urban expansion, taking into account protection laws of natural and agricultural land. This type of model has not been tested on developing cities and as such it corresponds to a new planning contribution for planners who have no concept of spatially how their urban areas have changed over time and where the growth is occurring. In this case, it has been calibrated over the period of 1986-1996, and then applied to predict the location of the built-up growth over the next 10 years (1996-2006). These results can provide local authorities and other stakeholders with information towards decision support documents for future planning and monitoring plans. Moreover, they can be updated systematically through the integration of remote sensing data.     

黑河综合遥感联合试验研究进展:水文与生态参量遥感反演与估算

介绍了“黑河综合遥感联合试验”在水文和生态变量与参数反演、估算和模型应用方面取得的进展。在水文变量遥感方面,利用车载双偏振多普勒雷达在黑河上游和中游分别开展了高精度降水观测,获取了后向散射系数和极化信息与降水强度之间的定量关系。在综合利用多源观测信息,改进和发展蒸散发估算模型方面取得了实质性的进展。发展了利用K和Ka波段机载微波辐射计数据反演山区积雪深度的方法。针对SAR观测数据反演土壤水分中地表粗糙度的显著干扰,发展了消除粗糙度影响的反演方法。在生态过程遥感参量估算方面,提出了一种基于机载激光雷达和高分辨率光学影像的高精度地物信息分类方法。发展了从高光谱航空遥感提取植被自然光照下的荧光,并与NDVI结合的C3/C4植被分类方法。发展和改进了使用多角度、多光谱观测反演叶面积指数的方法,挖掘了激光雷达在植被垂直结构探测上的潜力,探索了叶面积指数遥感中的尺度转换规律。发展了利用高光谱数据中的荧光信息反演光能利用率的新方法;建立了考虑土壤反射率、冠层结构等因素的光合作用有效辐射比率反演模型;改进了利用遥感估计生态系统生产力的模型。发展了利用高光谱遥感数据提取叶绿素含量和叶绿素荧光强度的方法。     

青藏高原冰川、积雪与地质灾害空间观测研究态势分析

气候变化带来的一系列严重问题越来越成为人类关注的焦点。21世纪初启动的世界气候研究计划(WCRP)新的核心计划——气候与冰冻圈计划(Climate and Cryosphere,CliC),使得冰冻圈研究成为国际热点的标志。由于青藏高原冰川积雪对气候变化的敏感性,以及地质灾害常发的特殊性,近年来中国、印度、美国、日本、德国等国家部署了一系列研究计划和研究项目,发表了大量的青藏高原冰川、积雪和地质灾害空间观测机理与应用的论文。通过文献计量分析这些论文可以反映出国际上青藏高原冰川、积雪与地质灾害空间观测研究的进展和发展态势。以SCIE中检索到的2000~2015年间与青藏高原冰川、积雪与地质灾害空间观测研究相关的论文、研究综述和学术会议论文等相关文献为基础,分析了国际地球关键带研究的总体研究概况、主要研究主体(国家和机构)分布和不同时期的研究主题和热点、学科领域分布、研究合作及未来发展态势等特征。     

基于“3S”技术的县级土地资源动态监测技术系统

土地资源日新月异的变化使得传统的土地资源管理手段无法满足土地资源信息及时更新的要求。探讨了利用遥感、地理信息系统和全球定位系统为代表的“3S”技术进行县级土地资源动态监测和更新的原理和方法。遥感是进行土地利用变化动态监测,发现土地利用变化区域的主要手段。全球定位系统接收仪用于对变化区域进行现场精确定位和实测。实测的变更数据可用于对原有的地理信息系统本底数据库进行修改,从而完成对土地资源的动态监测和数据库的及时更新。福清市土地资源动态监测技术系统就是利用“3S”技术建立起来的业务运行系统。系统所具备的功能可以满足县级土地资源的动态监测和及时更新。     

Global estimates of the land-atmosphere water flux based on monthly AVHRR and ISLSCP-II data, validated at 16 FLUXNET sites

Numerous models of evapotranspiration have been published that range in data-driven complexity, but global estimates require a model that does not depend on intensive field measurements. The Priestley-Taylor model is relatively simple, and has proven to be remarkably accurate and theoretically robust for estimates of potential evapotranspiration. Building on recent advances in ecophysiological theory that allow detection of multiple stresses on plant function using biophysical remote sensing metrics, we developed a bio-meteorological approach for translating Priestley-Taylor estimates of potential evapotranspiration into rates of actual evapotranspiration. Five model inputs are required: net radiation (R_n), normalized difference vegetation index (NDVI), soil adjusted vegetation index (SAVI), maximum air temperature (T_max), and water vapor pressure (ea). Our model requires no calibration, tuning or spin-ups. The model is tested and validated against eddy covariance measurements (FLUXNET) from a wide range of climates and plant functional types—grassland, crop, and deciduous broadleaf, evergreen broadleaf, and evergreen needleleaf forests. The model-to-measurement r² was 0.90 (RMS = 16 mm/month or 28%) for all 16 FLUXNET sites across 2 years (most recent data release). Global estimates of evapotranspiration at a temporal resolution of monthly and a spatial resolution of 1° during the years 1986-1993 were determined using globally consistent datasets from the International Satellite Land-Surface Climatology Project, Initiative II (ISLSCP-II) and the Advanced Very High Resolution Spectroradiometer (AVHRR). Our model resulted in improved prediction of evapotranspiration across water-limited sites, and showed spatial and temporal differences in evapotranspiration globally, regionally and latitudinally.     

An assessment of photosynthetic light use efficiency from space: Modeling the atmospheric and directional impacts on PRI reflectance

Estimation of photosynthetic light use efficiency (ε) from satellite observations is an important component of climate change research. The photochemical reflectance index, a narrow waveband index based on the reflectance at 531 and 570 nm, allows sampling of the photosynthetic activity of leaves; upscaling of these measurements to landscape and global scales, however, remains challenging. Only a few studies have used spaceborne observations of PRI so far, and research has largely focused on the MODIS sensor. Its daily global coverage and the capacity to detect a narrow reflectance band at 531 nm make it the best available choice for sensing ε from space. Previous results however, have identified a number of key issues with MODIS-based observations of PRI. First, the differences between the footprint of eddy covariance (EC) measurements and the MODIS footprint, which is determined by the sensor's observation geometry make a direct comparison between both data sources challenging and second, the PRI reflectance bands are affected by atmospheric scattering effects confounding the existing physiological signal. In this study we introduce a new approach for upscaling EC based ε measurements to MODIS. First, EC-measured ε values were “translated” into a tower-level optical PRI signal using AMSPEC, an automated multi-angular, tower-based spectroradiometer instrument. AMSPEC enabled us to adjust tower-measured PRI values to the individual viewing geometry of each MODIS overpass. Second, MODIS data were atmospherically corrected using a Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm, which uses a time series approach and an image-based rather than pixel-based processing for simultaneous retrievals of atmospheric aerosol and surface bidirectional reflectance (BRDF). Using this approach, we found a strong relationship between tower-based and spaceborne reflectance measurements (r² = 0.74, p < 0.01) throughout the vegetation period of 2006. Swath (non-gridded) observations yielded stronger correlations than gridded data (r² = 0.58, p < 0.01) both of which included forward and backscatter observations. Spaceborne PRI values were strongly related to canopy shadow fractions and varied with different levels of ε. We conclude that MAIAC-corrected MODIS observations were able to track the site-level physiological changes from space throughout the observation period.