ETM+卫星影像极地云层检测及分析

云一直是遥感图像预处理和分析中的一大难点,本文在分析南极地区成像特点的基础上,试图利用增强型主题成像传感器(ETM+)获取影像的多波段特点,对南极格罗夫山地区ETM+卫星影像进行云的检测。结果表明,该方法不仅能比较成功地检测极地云层像元,而且能有效地去除部分厚云的影响。     

体育场馆产业虚拟集群的构建

基于互联网技术在产业领域全面渗透的发展形势,部分学者提出“网络空间邻近性将取代地理空间邻近性”的论断,而另一部分研究结论坚持认为网络信息技术与平台是线下产业转型升级的“催化剂”,同时提出线下实体产业自身及其关联产业之间的地理要素对线上虚拟平台的构建与发展具有重要意义。据此,文章从地理空间的视角,试图阐释体育场馆虚拟集群构建的地理学研究基础和关注重点,分析体育场馆地理聚集效应无法形成的原因,总结归纳产业虚拟集群具有促进产业聚集形态、提高规模经济效益、建立分工协作关系、带动合作与竞争氛围、形成柔性化创新模式等作用,提出构建虚拟集群是未来体育场馆产业发展的重要形式之一。目前,中国体育场馆产业虚拟集群是横向各成员间合作与竞争的利益价值链,纵向是供需两端线上下产销价值链,共同构成了集群基本的结构体系;根据集群产业的主体规模、地理位置、产权属性和网络化程度等,场馆产业虚拟集群可分为单体型、连锁型、联盟型;而根据场馆产业集群的结构体系和功能特征,其发展过程需历经技术融合、产品改造、结构优化3个升级阶段。最终,建议通过正确认识场馆虚拟集群构建的地理性涵义,持续提升线下场馆服务的核心竞争力,发挥政府的政策支持和牵头结盟作用,建立场馆虚拟集群成员准入监督机制,为虚拟产业集群的创新发展提供理论与实践指导。     

相干声纳多波束与传统型多波束测深系统综合对比与实验分析

在工作原理、技术参数、采集软件和处理软件功能与操作,以及数据实测等方面对相干声纳多波束测深系统Geoswath Plus和传统型多波束测深系统Seabeam 1180进行了详细对比。对比表明,两套多波束系统的工作原理完全不同;传统型多波束测深系统在探头下方数据密集,两侧的数据逐渐变稀,相干声纳多波束测深系统在探头正下方的数据比较稀疏,探头两侧的数据较密集;相干声纳多波束测深系统Geoswath Plus的采集和处理软件实现了一体化,具有较直观的数据质量监控功能,传统型多波束测深系统Seabeam 1180可应用的后处理软件较多,功能更丰富;通过实测数据验证,两套多波束测深系统在数据测量精度上具有较好的一致性,不符值数列的标准偏差为3%—4%。对比为多波束测深系统的引进和选型提供了参考依据。     

Duration of Eo-Alpine metamorphic events obtained from multicomponent diffusion modeling of garnet: a case study from the Eastern Alps

Rocks from the Micaschist–Marble Complex of the Wölz Tauern, which are part of the middle Austroalpine unit, contain large (up to 2 cm) garnet crystals that show clear evidence of multistage growth. Isotopic dating indicates that a Variscan (～270 Ma) garnet core was overgrown by new garnet formed during Eo-Alpine metamorphism at Cretaceous times. P-T paths for the Eo-Alpine metamorphism were obtained using the method of pseudosections (Powell and Holland in Metam Geol 16:309–343, 1998) and are consistent with earlier results from independent thermobarometry. Due to the large size of the garnets, growth zoning was preserved during amphibolite facies metamorphism at both Variscan and Alpine times. Full multicomponent diffusion modeling of compositional zoning at the interface of the Alpine and Pre-Alpine garnets in conjunction with the retrieved P-T paths allow average subduction/exhumation as well as heating/cooling rates to be retrieved. The modeling suggests that a minimum subduction/exhumation rate of ～4 cm/a and heating/cooling rates on the order of 100–260°C/Ma for a 60°C subduction angle are required to preserve the observed compositional zoning overall while modifying the zoning at the interface between two garnets to the extent observed. Such rapid rates of burial/exhumation are consistent with the results of direct GPS measurements of convergence rates at several orogenic belts as well as with inferred rates from modeling in the Alps and other areas. In combination, this indicates that such rapid rates are commonplace during metamorphism in collisional orogens and places important constraints on the rheological behavior of crustal blocks in such orogens.     

论“互联网+”天基信息服务

"互联网+"代表了一种新的社会形态,为改革、创新、发展提供广阔的网络平台。随着互联网与传统产业的不断融合,"互联网+"正深刻改造、影响多个传统行业。"互联网+"给卫星对地观测与导航创造了大众化、普及化、智能化和实时化天基信息服务的有力条件。无处不在的地球空间信息大数据具有体量大、速度快、模态多样和真伪难辨的特性,形成了"数据海量、信息缺失、知识难觅"的局面。要实现地球空间全天时、全天候、全地域服务于每个人的目标,根本上解决现有地球空间信息服务系统覆盖能力有限、响应速度慢、体系协同能力弱的问题,满足大数据时代对地球空间信息"4R"服务要求,需要构建与地面网络深度耦合的"互联网+"天基信息服务体系。结合中国空天信息技术发展情况,介绍了"互联网+"天基信息服务体系建设的实施思路,分别对实现"互联网+"天基信息服务3个不同级别的特点进行了重点阐述。面向"互联网+"天基信息服务系统的要求,对地球空间信息学的重点支撑技术和系统发展前景进行了展望。     

杭州湾底泥得克隆污染状况及来源的初步研究

随着含溴阻燃剂的进一步限用或禁用,氯代阻燃剂得克隆(Dechlorane Plus, DP)以其良好的热稳定性和电化学性能成为推荐的替代品之一。作为添加型氯代阻燃剂,DP很容易从产品中脱落而成为环境中广泛存在的污染物,但相关的研究仍十分匮乏。本研究测定了杭州湾海域4个底泥柱状样品中DP的残留及异构体特征,并对DP在该海域底泥中的时空分布和可能来源进行了初步分析。结果表明,syn-DP和anti-DP在底泥样品中的含量分别为BDL~17.7 pg/g干质量(平均为2.9±3.2 pg/g干质量)和1.4~38.1 pg/g 干质量(平均为8.0±8.5 pg/g干质量),其污染程度相对全球范围处于较低水平。空间分布表明金山工业区可能对杭州湾DP的污染有一定贡献,DP在柱状底泥中的垂直分布未发现明显变化趋势。本研究中DP的f_syn平均值为0.25~0.28,表明研究海域底泥中的DP可能来自于远距离传输。     

气候变化和工程活动对青藏铁路沿线植被指数时空变化的影响

基于1982-2015年的GIMMS NDVI3g+及同期气候数据,利用最大值合成法获得青藏铁路沿线直接影响区和生态背景区的年内NDVI最大值、年际NDVI平均值,对其进行了趋势分析、变异分析、气候相关分析和残差分析,部分结果用MODISNDVI(2001-2018年)进行了验证.研究表明:①青藏铁路年际NDVI高度响...     

Development of large-area land cover and forest change indicators using multi-sensor Landsat imagery: Application to the Humber River Basin,Canada

Monitoring ecological indicators is important for assessing impacts of human activities on ecosystems. A means of identifying and applying appropriate indicators is a prerequisite for: environmental assessment; better assessment and understanding of ecosystem health; elucidation of biogeochemical trends; and more accurate predictions of future responses to global change, particularly those due to anthropogenic disturbance. The challenge is to derive meaningful indicators of change that capture the complexities of ecosystems yet can be monitored consistently over large areas and across time. In this study, methods for monitoring indicators of land cover (LC) and forest change were developed using multi-sensor Landsat imagery. Mapping and updating procedures were applied to the Humber River Basin (HRB) in Newfoundland and Labrador, one of four test sites in Canada selected for testing the development of national-scale methods. Procedures involved unsupervised clustering and labeling of baseline imagery, followed by image-to-image spectral clustering to derive binary change masks within which new LC types were classified for non-baseline imagery. Updated maps were compatible with the baseline map and reflected change in LC for three time periods: 1976–1990, 1990–2001, and 2001–2007. From the LC products, several change indicators were quantified including: forest depletion, forest regeneration, forest change, net forest change, and annual rates of change. The procedures were validated using field plots to assess the accuracy of the 2007 LC product (74.2% for 10 LC classes) and change classes observed from 2001 to 2007 (87.8% for four change classes: depletion, regeneration, non-treed class no change, and treed class no change). Methods were considered to be highly efficient and operationally feasible over large areas spanning multiple Landsat scenes. Specific results for the test site provided trend information supporting land and resource management in the HRB region.     

GeoSwath与Klein 3000的综合对比及实验分析

GeoSwath Plus系统利用相干原理能同时得到水深数据和声纳图,与传统侧扫声纳存在一定差异。本文对GeoSwath Plus 125 kHZ系统和Klein 3000系统从工作原理、技术参数、数据采集和后处理平台以及实测数据等方面进行了对比。结果表明:二者接收数据存在差异,导致两者的用途也存在差异;GeoSwath Plus系统相比Klein 3000更加复杂,但适用水深范围较小;GeoSwath Plus采集软件较少,对后处理软件的要求更高,而Klein 3000数据采集和后处理软件都有多种选择;通过实测数据的比较发现,GeoSwath Plus的定位精度更高,但由于发射波束水平开角大于Klein 3000,加之采用悬挂式安装,导致得到的声纳图像对比度和分辨率比传统侧扫声纳Klein 3000要差一些。     

华南北热带11.5―2.5 ka B.P. 温度集成重建与特征分析

基于“综合-比例法”（Composite Plus Scale,CPS）,利用近年来已发表的数据集成重建我国华南北热带地区11.5―2.5 ka B.P.温度变化序列。结果表明,该地区冷暖变化可以分为三大阶段：11 500―9 500 a B.P.为全新世早期阶段;9 500―4 000 a B.P.为全新世大暖期阶段;4 000―2 500 a B.P.开始出现降温过程。功率谱和小波分析表明：华南北热带气候变化具有多时段、多尺度冷暖周期变化特征,在千年尺度上,1.3 ka和3.3~3.9 ka是其冷暖变化的主要周期。序列中可以识别出一系列气候波动事件,如8.2 ka、7.9 ka、7.1 ka、4.1 ka气候事件。交叉小波谱分析表明：ENSO对华南北热带地区温度变化有着显著影响,特别是7 ka B.P.以来其影响进一步加强。通过与其他序列的对比发现：华南北热带地区的气候变化是对全球变化的响应,但也同样存在区域差异。