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排序方式: 共有185条查询结果,搜索用时 15 毫秒
31.
Bas J. van Ruijven Marc A. Levy Arun Agrawal Frank Biermann Joern Birkmann Timothy R. Carter Kristie L. Ebi Matthias Garschagen Bryan Jones Roger Jones Eric Kemp-Benedict Marcel Kok Kasper Kok Maria Carmen Lemos Paul L. Lucas Ben Orlove Shonali Pachauri Tom M. Parris Anand Patwardhan Arthur Petersen Benjamin L. Preston Jesse Ribot Dale S. Rothman Vanessa J. Schweizer 《Climatic change》2014,122(3):481-494
This paper discusses the role and relevance of the shared socioeconomic pathways (SSPs) and the new scenarios that combine SSPs with representative concentration pathways (RCPs) for climate change impacts, adaptation, and vulnerability (IAV) research. It first provides an overview of uses of social–environmental scenarios in IAV studies and identifies the main shortcomings of earlier such scenarios. Second, the paper elaborates on two aspects of the SSPs and new scenarios that would improve their usefulness for IAV studies compared to earlier scenario sets: (i) enhancing their applicability while retaining coherence across spatial scales, and (ii) adding indicators of importance for projecting vulnerability. The paper therefore presents an agenda for future research, recommending that SSPs incorporate not only the standard variables of population and gross domestic product, but also indicators such as income distribution, spatial population, human health and governance. 相似文献
32.
Integrated assessment of global environmental change is a relatively new field that is beginning to define itself and its forms of practice. As yet, the field has not grappled directly with issues of quality control and assessment of quality, and this work is a first attempt in that direction. We argue that if integrated assessment is to be successful in the long run, then building and maintaining credibility via quality control procedures is a necessary condition for realizing its potential. We highlight a number of pitfalls in the practice of integrated assessment, and discuss their causes. We buttress our concerns using examples from both within climate change integrated assessment, and from the history of other similar endeavors. We also provide a number of suggestions that we hope will serve to alleviate some of these pitfalls. For instance, tools, methods, and assumptions from disciplines form archetypes for components in integrated assessment models, and we need to apply greater scrutiny to these archetypes. Further, tools which may be reasonable to use in particular disciplinary, geographical, or temporal contexts may be unsuited to the broader contexts inherent in integrated assessment studies of global environmental change. 相似文献
33.
Hyun-Chul Lee Thomas L. Delworth Anthony Rosati Rong Zhang Whit G. Anderson Fanrong Zeng Charles A. Stock Anand Gnanadesikan Keith W. Dixon Stephen M. Griffies 《Climate Dynamics》2013,40(1-2):327-340
The impact of climate warming on the upper layer of the Bering Sea is investigated by using a high-resolution coupled global climate model. The model is forced by increasing atmospheric CO2 at a rate of 1% per year until CO2 reaches double its initial value (after 70 years), after which it is held constant. In response to this forcing, the upper layer of the Bering Sea warms by about 2°C in the southeastern shelf and by a little more than 1°C in the western basin. The wintertime ventilation to the permanent thermocline weakens in the western Bering Sea. After CO2 doubling, the southeastern shelf of the Bering Sea becomes almost ice-free in March, and the stratification of the upper layer strengthens in May and June. Changes of physical condition due to the climate warming would impact the pre-condition of spring bio-productivity in the southeastern shelf. 相似文献
34.
本文是机器视觉参量下的三维数字摄影测量智能构象第三部分,以仿生复眼运动目标捕获的3-3-2信息处理方式为切入点,提出生物利用复眼进行三维成像的基本原理,然而由于传统仿生视觉受到硬件条件制约,所以本文在仿生复眼3-3-2信息获取理论的基础上,利用新一代微透镜阵列光场相机技术,提出了一种以单张光场影像获取目标场景深度信息的方法,并将其应用至绝对深度测量中。由于光场影像的一个重要的特性在于记录进入相机的不同光线的强度与方向信息,本文提出利用光线信息进行多深度层次重聚焦的方法,通过对物点在不同层次进行聚焦代价计算,确定出物点成像的平面,最终构建基于物点成像平面位置的深度图。与传统的光场深度估计相比,本文方法计算的深度图可以显著提升分辨率,且不依赖于光场微透镜的数目。为了验证本文方法的有效性,利用本文的算法与现有的深度信息的算法进行深度计算的比较。 相似文献
35.
F. A. J. Abernethy A. B. Verchovsky N. A. Starkey M. Anand I. A. Franchi Monica M. Grady 《Meteoritics & planetary science》2013,48(9):1590-1606
Angrites are a small group of ancient basaltic achondrites, notable for their unusual chemistry and extreme volatile depletion. No comprehensive study of indigenous light elements currently exists for the group. Measurement of the abundances and isotopic composition of carbon and nitrogen could provide information pertaining to the evolution of the angrite parent body. Bulk‐sample stepped combustion analyses of five angrites and a glass separate from D'Orbigny were combined with earlier data and acid dissolution experiments of carbonates found in D'Orbigny to compile an inventory of indigenous carbon and nitrogen. Indigenous carbon combusted between 700 °C and 1200 °C, with abundances of 10–140 ppm and a mass‐weighted δ13C of ?25 to ?20‰ with the exception of D'Orbigny (δ13C approximately ?5‰). Nitrogen was released at 850–1200 ºC, 1–20 ppm with a δ15N ?3‰ to +4‰; again, D'Orbigny (δ15N approximately +20 to +25‰) was an exception. We interpret these components as largely indigenous and decoupled; the carbon in graphitic or amorphous form, while the nitrogen is present as a dissolved component in the silicates. No relationship with the textural sub‐classification of angrites is apparent. We suggest that the angrite parent body contains a reservoir of reduced carbon and thus may have undergone a change in redox conditions, although the timing and mechanism for this remain unclear. 相似文献
36.
Anand Sivaramakrishnan 《Celestial Mechanics and Dynamical Astronomy》1989,46(1):35-48
Linked twist maps of ergodic theory are modified to provide a model for chaotic orbits in ‘double bowl’ potentials in conservative
systems, e.g. direct ‘exchange’ orbits in the planar restricted problem of three bodies. The maps are typically ergodic (and
mixing), and provide a clue to the nature of relaxation or diffusion in chaotic Hamiltonian systems. 相似文献
37.
Rabi Bastia M. Radhakrishna Suman Das Anand S. Kale Octavian Catuneanu 《Marine and Petroleum Geology》2010
The passive Eastern Continental Margin of India (ECMI) evolved during the break up of India and East Antarctica in the Early Cretaceous. The 85°E ridge is a prominent linear aseismic feature extending from the Afanasy Nikitin Seamounts northward to the Mahanadi basin along the ECMI. Earlier workers have interpreted the ridge to be a prominent hot spot trail. In the absence of conclusive data, the extension of the ridge towards its northern extremity below the thick Bengal Fan sediments was a matter of postulation. In the present study, interpretation of high resolution 2-D reflection data from the Mahanadi Offshore Basin, located in the northern part of the ridge, unequivocally indicates continuation of the ridge across the continent–ocean boundary into the slope and shelf tracts of the ECMI. Its morphology and internal architecture suggest a volcanic plume related origin that can be correlated with the activity of the Kerguelen hot spot in the nascent Indian Ocean. In the continental region, the plume related volcanic activity appears to have obliterated all seismic features typical of continental crust. The deeper oceanic crust, over which the hot spot plume erupted, shows the presence of linear NS aligned basement highs, corresponding with the ridge, underlain by a depressed Moho discontinuity. In the deep oceanic basin, the ridge influences the sediment dispersal pattern from the Early Cretaceous (?)/early part of Late Cretaceous times till the end of Oligocene, which is an important aspect for understanding the hydrocarbon potential of the basin. 相似文献
38.
Acta Geotechnica - The identification of contaminated soils has gained increasing interest over the decades in the geoenvironmental issues. In this study, a probabilistic method based on the... 相似文献
39.
Soil-bentonite (SB) backfill is used extensively in cutoff walls at landfill sites; the walls are used as engineered geotechnical barriers for contaminant control. With increasing bentonite content, the coefficient of consolidation and hydraulic conductivity of the SB decrease. However, when the bentonite content is increased beyond a certain percentage, the hydraulic conductivity of the SB decreases very little. One of the aims of this paper is to introduce the concept of optimal bentonite content (OBC) for SB cutoff walls, in which the hydraulic conductivity (kh) is expected to be lower than 1?×?10?9 m/s. Additionally, the paper introduces a new index consolidation stress ratio, cvσ′, which is used to obtain the OBC. For this study, the initial water contents of the SB backfill material are selected to be 0.8, 1.0, and 1.2 times their corresponding liquid limits. The clayey soils are amended with different bentonite contents, 0, 5, 8, and 10% (by dry weight basis) for the oedometer tests. Then, piezocone penetration test (CPTU) is applied in SB cutoff wall at a landfill site in Jingjiang city, China. The results of the laboratory and field studies show that the introduction of a new index, cvσ′, is very useful for calculating the OBC and for evaluating the coefficient of consolidation and hydraulic conductivity of SB backfill. The advantage of SB backfill with OBC is that it can achieve the design requirement of very low hydraulic conductivity and improve the safety reserves. 相似文献
40.
When a piezocone (CPTU) penetrates the ground, pore pressures are set up due to the stress changes. Pore pressure dissipation occurs in the subsequent consolidation process in a manner dependent on the initial stress distribution. The process of analysis can be used to interpret the consolidation parameters from CPTU data based on strain path approach. For the two approaches to the CPTU analysis, the Houlsby and Teh method used an elastic-plastic model, while the Levadoux and Baligh solution used parameters specifically appropriate for Boston Blue Clay. This article discusses a comparison between the two theoretical predictions and field CPTU measurements deployed in Jiangsu (China) Quaternary clays. The values of the coefficient of consolidation calculated from the two methods are then compared with high-quality laboratory tests. Both theoretical predictions provide good agreement for the shape of the dissipation curve, but the predicted c h values are different and thought should indeed be given to the use of an appropriate value of G/s u. 相似文献