Coupling Earth System Model and Integrated Assessment Model     

Dong Wenjie  Yuan Wenping  Teng Fei  Hao Zhixin  Zheng Jingyun  Wei Zhigang  Chou Jieming  Liu Changxin  Qi Tianyu  Yang Shili  Yan Dongdong  Zhang Jing 《地球科学进展》2016,31(12):1215-1219

According to the guideline of National Key Research and Development Project, this project aims at developing a world-class Integrated Assessment Model (IAM) in China, which will be used to assess the impacts of climate change on economy system. The objects of this project are to ① Improve the spatial resolution of Earth System Model (ESM); ② Modify the Integrated Assessment Model; ③ Couple the ESM and IAM; ④ Evaluate the impacts of climate change on society and economy. This project will solve two key scientific questions: how to identify the impacts of climate change in the IAM; How much the impacts of climate change on economy in China. Meanwhile, two techniques will be developed to complete the mission of this project: Simulate of small-scale human activities in the EAM and spatial and temporal resolution match of ESM and IAM.  相似文献   

Chinese Earth Science at Its Turning Point     

Wang Pinxian 《地球科学进展》2016,31(7):665-667

Since 2010, China has become the second biggest publisher of scientific research papers in the world, but remains far behind the global leadership with regards to the ability of creative innovation. Just like its economy, Chinese science is at a turning point, and the key is to avoid the “Middle-income trap”. Instead of blindly going after quantity of SCI publications, Earth science in China is to address major scientific problems and to perform transition to a new level of innovative researches. This is a written speech to the 4^th Conference on Earth System Science,Shanghai.  相似文献   

Land subsidence and earth fissures due to groundwater withdrawal in the Southern Yangtse Delta,China   总被引：1，自引：0，他引：1  

Yun Zhang  Yu-Qun Xue  Ji-Chun Wu  Jun Yu  Zi-Xin Wei  Qin-Fen Li 《Environmental Geology》2008,55(4):751-762

Excessive extraction of groundwater has caused severe land subsidence and earth fissures in the Southern Yangtse Delta, China. Based on field data, the temporal and spatial distribution of land subsidence is investigated and the causes for earth fissures are analyzed. The areal distribution of the land subsidence is closely related to the cones of depression in the main exploited aquifers. The compaction of a hydrostratigraphic unit depends on its mechanical behavior, thickness, compressibility, and the piezometric level changing. The primary subsidence layers in Shanghai have been the first aquitard before 1990 and the third confined aquifer since then. But the second aquitard unit was the primary subsidence layer in Changzhou. Earth fissures, trending in several directions, occurred in the Husu tectonic zone. They were mainly caused by differential subsidence and horizontal displacement that resulted from tensile stress and shear stress in units. The majority of fissures in the study area are tensile.  相似文献   

Google Earth和ArcGIS 9.2软件在太湖水污染及蓝藻监测数据展现中的应用   总被引：1，自引：0，他引：1  

李旭文  黎刚  缪蓓蓓 《国土资源遥感》2008,(1):97-99

利用Google Earth和 ArcGIS 9.2软件对太湖水污染及蓝藻监测数据进行了集成和发布,为形象直观展示太湖生态环境,分析太湖水环境质量及蓝藻空间分布特征提供了很好的技术支持.  相似文献   

Cost Optimization of Reinforced Earth Walls   总被引：1，自引：0，他引：1  

P. K. Basudhar  Amol Vashistha  Kousik Deb  Arindam Dey 《Geotechnical and Geological Engineering》2008,26(1):1-12

This paper deals with optimum cost (objective function) design of geosynthetic reinforced earth retaining walls subjected to static and dynamic loading. The design restrictions are imposed as design constraints in the analysis. Choice of the initial designed length and strength of the reinforcement, which are the elements of the design vectors are made in a way that it forms an initial feasible design vector. Thus the problem is one of mathematical programming. The constraints and the objective function being nonlinear in nature, the Sequential Unconstrained Minimization Technique (SUMT) has been used in conjunction with conjugate direction and quadratic fit methods for multidimensional and unidirectional minimization to arrive at the optimal (minimum) cost of the reinforced earth wall. Optimal cost tables are presented for different combinations of the loading and the developed procedure is validated by taking up an example problem. It has been found from the typical example problem that saving of the order of 7–8% can be made over the conventional design of mechanically stabilized earth (MSE) walls with the aid of design charts.  相似文献   

中国科学院固体地球科学知识创新十年回眸     

周少平  王辉 《地球科学进展》2008,23(1):71-75

中央批准中国科学院进行知识创新工程试点工作已经十年,十年来作为院资源环境科学四大分支之一的固体地球科学研究进展显著。回顾了十年来本领域创新研究单元的新建和调整工作、重点实验室和野外台站的工作进展、国家级的973项目工作的成绩、重大创新成果的产出和获奖。作者认为,中国科学院固体地球科学领域的研究将呈现更加光明的前景,力争在不久的将来跻身固体地球科学研究世界先进行列。  相似文献   

地球的时变主惯性矩和变化的自转(英文)   总被引：1，自引：0，他引：1  

SHEN Wenbin CHEN Wei SUN RongSHEN Wenbin  School of Geodesy  Geomatics  Wuhan University  Luoyu Road  Wuhan  China  The Key Laboratory of Geospace Environment  Geodesy  Wuhan University  Luoyu Road  Wuhan  China. 《地球空间信息科学学报》2008,(2)

Based on the gravity field models EGM96 and EIGEN-GL04C, the Earth's time-dependent principal moments of inertia A, B, C are obtained, and the variable rotation of the Earth is determined. Numerical results show that A, B, and C have increasing tendencies; the tilt of the rotation axis increases 2.1×10-8 mas/yr; the third component of the rotational angular velocity, ω 3, has a decrease of 1.0×10-22 rad/s2, which is around 23% of the present observed value. Studies show in detail that both θ and ω 3 experience complex fluctua-tions at various time scales due to the variations of A, B and C.  相似文献   

Evolution of the composition of seawater through geologic time, and its influence on the evolution of life   总被引：2，自引：2，他引：0  

Tsuyoshi Komiya  Takafumi Hirata  Kouki Kitajima  Shinji Yamamoto  Takazo Shibuya  Yusuke Sawaki  Tomoko Ishikawa  Degan Shu  Yong Li  Jian Han 《Gondwana Research》2008,14(1-2):159

The redox state of the surface environment of the early Earth is still controversial, and a detailed and quantitative estimate is still lacking. We carried out in-situ analyses of major, trace, and rare-earth elements of carbonate minerals in rocks with primary sedimentary structures in shallow and deep sea-deposits, in order to eliminate secondary carbonate and contamination of detrital materials, and to estimate the redox condition of seawater through time. Based on the Ce content and anomalies of the carbonate minerals at given parameters of atmospheric CO₂ content (pCO₂) and Ca content of seawater, we calculated the oxygen contents of shallow and deep seawater, respectively. The results show that the oxygen content of the deep sea was low and constant until at least 1.9 Ga. The oxygen content of shallow seawater increased after 2.7 Ga, but fluctuated. It became quite high at 2.5 and 2.3 Ga, but eventually increased after the Phanerozoic. In addition, the calculation of a high pCO₂ condition shows that seawater was more oxic even in the Archean than at present, suggesting a relatively low pCO₂ through geologic time.Our detailed calculations from compositions of carbonate minerals in Three Gorge area, south China show a low oxygen content of seawater after the Snowball Earth until the late Ediacaran, an increase in the late Ediacaran, and a significant decrease around the Precambrian–Cambrian and Nemakit/Daldynian–Tommotian boundaries. These variations were possibly caused by global regression and dissolution of methane hydrates.  相似文献   

Models on Snowball Earth and Cambrian explosion: A synopsis   总被引：5，自引：5，他引：0  

S. Maruyama  M. Santosh 《Gondwana Research》2008,14(1-2):22

During the late Proterozoic from 1000 to 542 Ma, the Earth is thought to have been frozen at least during two times: in the Sturtian (715–680 Ma) and in the Marinoan (680–635 Ma) global glaciations. Following the Marinoan Snowball Earth, large multi-cellular animals of the Ediacara fauna flourished as a prelude to the Phanerozoic world. Here we summarize the most popular models on the cause and cessation of Snowball Earth. Episodic decrease of greenhouse gas occurs through the effect of erosion and weathering promoted by either mountain building or by an increase in the coastlines during the break-up of supercontinents. Effects on the globe caused by true polar wander, eruption of voluminous flood basalts, or dramatic reduction in planetary obliquity can also lead to ice ages and mass extinction. A radically revised concept based on Earth's magnetic intensity has also been proposed, which explains the true polar wander through a quasi-polar dynamo model. The ‘switch-on’ and ‘switch-off’ of the Earth's strong dynamo can lead to the onset and disappearance of the Snowball Earth. The galactic model infers that gamma ray burst associated with starburst creates huge amounts of clouds which would cut off sun rays and freeze the Earth.The Snowball Earth event is considered to have exerted a significant control on the subsequent revolutionary changes in the evolution of life forms. Although according to the biological clock, extensive re-organisation of genome is thought to have been completed by around 900 Ma, the evolution of modern life in Cambrian occurred only after the geochemical bridge was in place with elevated oxygen and nutrient levels in lakes that developed within continental rifts where the hydrothermal system in the granitic basement created the chemical environment enriched in Ca²⁺, Fe²⁺, V, Mo, HCO₃, phosphate and other elements required for building the skeleton and bone of the first modern animals. With cosmic radiation exerting a significant control on the mutation, the Neoproterozoic Earth history illustrates the possible link from Galaxy to the genome level.  相似文献   

Metamorphic decarbonation in the Neoproterozoic and its environmental implication   总被引：2，自引：1，他引：1  

S. Omori  M. Santosh 《Gondwana Research》2008,14(1-2):97

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.  相似文献