Metamorphic decarbonation in the Neoproterozoic and its environmental implication

Metamorphic decarbonation reactions and volcanic degassing lead to significant influx of CO₂, a major greenhouse gas, into the ocean-atmosphere system from the solid Earth. Here we present quantitative estimates on CO₂ derived through metamorphic degassing during ultrahigh-temperature (UHT) metamorphism in the Neoproterozoic through the mineralogical and geological analyses of the UHT decarbonation. Our computations show that an extra flux of CO₂ was added to the atmosphere through a Himalayan scale UHT metamorphism to the extent of 6 × 10¹⁶ to 3.0 × 10¹⁸ mol/my, for a duration of 10 my. A calculation of the impact of the extra CO₂ influx to the global mean temperature in the context of carbon cycle and greenhouse effect of CO₂ shows that at the peak influx stage, the steady state temperature would be raised by 4 °C from 15 °C and by 13 °C from 4 °C. Our results have important bearing in evaluating the mechanism of melting and the duration of the Snowball Earth. Our estimate of the maximum degassing rate during UHT metamorphism suggests that the duration of the Marinoan snowball Earth was probably shorter, and the recovery from an ice-covered Earth to ocean-covered Earth was faster than previous estimates.     

Virtual Earth API在Web地图服务中的应用

自2005年地图搜索服务兴起以及Google公司在线地图Google Map的发布,web地图服务成为新一轮竞争热点,微软、雅虎及亚马逊等公司纷纷参与竞争。本文介绍了微软Virtual Earth API最为重要的几个功能及其实现方法,演示了使用Virtual Earth技术建立Web地图服务的方法,为学习微软Virtual Earth制图技术和使用Virtual Earth地图控件提供借鉴。     

郑州市空间信息基础设施建设与应用研究

数字地球是21世纪的重大技术工程,数字城市是数字地球应用的主要方面之一。依据我国数字城市建设的现状,提出构建"郑州市空间信息基础设施",并对其内容、应用、关键技术、实现策略等进行了论述及探讨。     

Teaching Topographic Map Skills and Geomorphology Concepts with Google Earth in a One-Computer Classroom

Teaching high-school geomorphological concepts and topographic map reading entails many challenges. This research reports the applicability and effectiveness of Google Earth in teaching topographic map skills and geomorphological concepts, by a single teacher, in a one-computer classroom. Compared to learning via a conventional instructional method, students learning with Google Earth do not have different geomorphological concepts development because both settings enable students to learn with similar static representation. However, students learning with Google Earth improve topographic map skills significantly compared to the conventional instructional method. This is because of the 3D landscape visualization and prior knowledge connections available with Google Earth.     

科学数据共享实践：以国家地球系统科学数据中心为例

地球系统科学是一门综合性交叉学科,起源于全球变化研究,受益于遥感技术进步,现已进入大数据时代,人工智能技术成为解决地球系统科学前沿问题的新手段。科学数据共享是推动科学发展、提升数据价值的关键,经过长期的探索和实践,全球已形成完善的数据资源管理政策与机制、持续的数据共享服务体系、多元化的科学数据整合模式,并且新的理念不断推动数据共享创新发展,其中“可发现、可访问、可互操作和可重用”原则和数据出版备受推崇。我国颁布了国家层面的政策法规,着重推动国家级科学数据中心建设、科技项目数据资源汇交及数据出版。借鉴国外数据共享经验,结合国内实际发展情况,我国探索出具有中国特色的地球系统科学数据资源分类体系,在元数据、分布式互操作、大数据分析和共享服务等关键技术方面都取得了重大突破。本文以国家地球系统科学数据中心为例,系统梳理了国内地球系统科学领域的数据共享实践进展,详细介绍了国家在地球系统科学领域的数据共享实践及其成效。国家地球系统科学数据共享工作已探索形成成熟稳定的运行服务机制、研制出适用于多源分散地球系统科学数据的标准体系、 建成多学科多时空尺度的地球系统科学数据库群、自主研发海量异构数据共享网络技术体系与服务系统,促进了地球系统科学的科学发展,同时也推动了数据共享理念的传播与推广。然而,数据孤岛现象、共享服务系统标准化程度低、系统技术标准未对接国际规范等问题仍然较为突出,阻碍了地球系统科学数据开放与共享。未来,随着共享个性化需求被激活,定制化的“数据+知识”服务有望成为主流趋势,将给数据共享带来新的机遇和挑战。     

台站插值技术对检测固体地球变化的影响分析

搜集了全球约4 000个GNSS测站实测数据(站坐标和速度场信息),对固体地球体积及其变化率进行计算分析。采用板块运动模型插值方法对台站进行插值,使全球测站分布更加均匀。利用Delaunay数学模型计算固体地球体积及其变化率的结果发现:基于板块运动模型进行台站插值可以有效地提高计算结果的误差精度,不会对地球最终形态变化结论产生影响,台站数量及其分布均匀程度对计算最终结果影响较大。     

Operational evapotranspiration estimates from SEVIRI in support of sustainable water management

This study aimed at evaluating the accuracy of the evapotranspiration (ET) operational estimates from the Meteosat Second Generation (MSG) Spinning Enhanced Visible Infra-Red Imager (SEVIRI) at a range of selected ecosystems in Europe. For this purpose in-situ eddy covariance measurements were used, acquired from 7 selected experimental sites belonging to the CarboEurope ground observational network over 2 full years of observations (2010–2011). Appraisal of ET accuracy was also investigated with respect to land cover, season and each site(s) degree of heterogeneity, the latter being expressed by the fractional vegetation cover (FVC) operational product of SEVIRI.Results indicated a close agreement between the operational product’s ET estimates and the tower based in-situ ET measurements for all days of comparison, showing a satisfactory correlation (r of 0.709) with accuracies often comparable to previous analogous studies. For all land cover types, the grassland and cropland sites exhibited the closest agreement (r from 0.705 to 0.759). In terms of seasons the strongest correlations were observed during the summer and autumn (r of 0.714 & 0.685 respectively), and with FVC the highest correlation of 0.735 was observed for the class FVC 0.75-1 when compared against the observed values for the complete monitoring period. Our findings support the potential value of the SEVIRI ET product for regional to mesoscale studies and corroborate its credibility for usage in many practical applications. The latter is of particular importance for water limiting environments, such as those found in the Mediterranean basin, as accurate information on ET rates can provide tremendous support in sustainable water resource management as well as policy and decision making in those areas.     

地球系统空间观测:从科学卫星到月基平台

五十多年来,全球性对地观测已形成强大的技术能力和系统体系,在不同应用领域发挥了重要作用。随着对陆地、大气、海洋研究的深入,地球系统科学和全球变化研究正在向空间对地观测技术提出新的重大战略性需求。本文描述了面向全球变化应对、发展全球变化系列科学卫星的方案;提出面向宏观地球科学现象探测、构建月基对地观测系统的设想;同时,作为宏观地球科学现象研究的一个方向,论述了利用地球科学卫星和月基对地观测技术开展全球变化"三极"对比研究的思路。     

Building a scientific and ecological earth–on an important field of geo-science: Geo-environment and construction engineering effect

This paper explores the 12 aspects of geo-environment and construction engineering, including the earth evolution, the structure of geological bodies, the comprehensive utilization of resources, the geo-environmental effect, the engineering construction, the sustainable development and, etc. This paper presents that the good environment could only be created through the conservation and efficient utilization of resources, the joint efforts of disaster prevention and mitigation, as well as the avoidance of adverse environmental effect caused by human activities. This paper concludes that, to build a scientific and ecological earth, the development laws of geo-science must be learnt.     

若尔盖县弯曲河流精细提取研究

利用Google Earth Engine遥感大数据云平台,以若尔盖县的弯曲河流为研究对象,以空间分辨率为10 m的Sentinel-2多光谱卫星遥感影像为数据源,选用归一化差分水体指数(NDWI)、改进型归一化差分水体指数(MNDWI)和自动水体提取指数(AWEI)相组合的方式,建立支持向量机模型,进行弯曲河流信息的提取;利用归一化差分水体指数、改进型归一化差分水体指数和自动水体提取指数,提取出弯曲河流信息,并与支持向量机模型提取的结果进行了比较。研究结果表明,利用归一化差分水体指数提取的弯曲河流的整体性和连续性最优;利用改进型归一化差分水体指数提取的地势复杂区域细小河流的精度较高;利用支持向量机模型提取的弯曲河流更为准确,并消除了山体和植物阴影对弯曲河流提取的影响;与利用3种指数提取的结果相比,支持向量机模型提取的弯曲河流的总体精度和用户精度都相对最高。