共查询到20条相似文献，搜索用时 31 毫秒
1.
Significant advances in regional groundwater flow modeling have been driven by the demand to predict regional impacts of human inferences on groundwater systems and associated environment.The wide availability of powerful computers,user friendly modeling systems and GIS stimulates an exponential growth of regional groundwater modeling.Large scale transient groundwater models have been built to analyze regional flow systems,to simulate water budget components changes,and to optimize groundwater developmen... 相似文献
2.
Bioturbation is a typically small scale yet potentially significant geological process altering rock properties by reworking. For many years, bioturbation studies found application in exploration geology to estimate paleobathymetry, interpreting depositional environment and identifying key stratigraphic surfaces. These act as vital inputs to the geological models, for determination of source rock potential, reservoir quality and modeling of petroleum systems. Recently geologists extended the application of bioturbation studies to address production related challenges. Recognizing the bioturbation effects and incorporating them in reservoir simulation models can improve production predictions and enhanced oil recovery operations. This paper discusses bioturbation and its effects on reservoir quality, its performance and production. 相似文献
3.
Exurbia from the bottom-up: Confronting empirical challenges to characterizing a complex system 总被引：2，自引：0，他引：2
Daniel G. Brown Derek T. Robinson Li An Moira Zellner William Rand Rick Riolo Bobbi Low 《Geoforum》2008,39(2):805-818
We describe empirical results from a multi-disciplinary project that support modeling complex processes of land-use and land-cover change in exurban parts of Southeastern Michigan. Based on two different conceptual models, one describing the evolution of urban form as a consequence of residential preferences and the other describing land-cover changes in an exurban township as a consequence of residential preferences, local policies, and a diversity of development types, we describe a variety of empirical data collected to support the mechanisms that we encoded in computational agent-based models. We used multiple methods, including social surveys, remote sensing, and statistical analysis of spatial data, to collect data that could be used to validate the structure of our models, calibrate their specific parameters, and evaluate their output. The data were used to investigate this system in the context of several themes from complexity science, including have (a) macro-level patterns; (b) autonomous decision making entities (i.e., agents); (c) heterogeneity among those entities; (d) social and spatial interactions that operate across multiple scales and (e) nonlinear feedback mechanisms. The results point to the importance of collecting data on agents and their interactions when producing agent-based models, the general validity of our conceptual models, and some changes that we needed to make to these models following data analysis. The calibrated models have been and are being used to evaluate landscape dynamics and the effects of various policy interventions on urban land-cover patterns. 相似文献
4.
基于Agent的模型(Agent-based models,ABM)研究已成为水资源管理研究理论与方法的重要补充。对水资源管理ABM研究进行归纳与展望,有助于探索优化中国水资源管理体制和机制。在阐述水资源管理ABM概念及内涵的基础上,提炼出主体决策规则和互作机制两个建模核心内容,并对其方法进行了归纳分析;从流域水资源优化配置、城镇居民用水管理和灌区水资源管理3个方面,对2009—2018年主要水资源管理ABM研究进行了综述;针对当前研究的难点与不足,提出未来研究重点:①拓展复杂适应理论在水资源管理领域的应用;②加强不确定性水资源管理ABM研究;③探索基于机器学习的决策规则建模方法;④重视参数校准和结果校验及检验方法;⑤加强模型表述格式标准化进程;⑥综合权衡水资源管理ABM框架。 相似文献
5.
干旱区内陆河流域生态水文综合集成研究 总被引：7，自引：1，他引：6
针对干旱区内陆河流域生态环境问题,面对国家重大需求及地球系统科学发展方向,指出内陆河流域生态水文综合集成研究的必要性,旨在为精细管理水资源,提高单方水产出效益（经济效益和生态效益）提供思路。以黑河流域为例,追踪流域研究历程,目前从野外调查试验观测,模型模拟到研究平台建设,黑河流域的数据知识的积累已基本具备开展流域生态水文综合集成的条件,但仍然存在着巨大的挑战。根据存在的问题,提出未来进行集成研究应加强的3个方面：①加强综合观测;②强调人文因素的定量研究和人文过程的研究;③重视模型、模拟方法在描述和反演地理真实中的应用。 相似文献
6.
Marios Sophocleous 《Hydrogeology Journal》2002,10(1):52-67
The interactions between groundwater and surface water are complex. To understand these interactions in relation to climate,
landform, geology, and biotic factors, a sound hydrogeoecological framework is needed. All these aspects are synthesized and
exemplified in this overview. In addition, the mechanisms of interactions between groundwater and surface water (GW–SW) as
they affect recharge–discharge processes are comprehensively outlined, and the ecological significance and the human impacts
of such interactions are emphasized. Surface-water and groundwater ecosystems are viewed as linked components of a hydrologic
continuum leading to related sustainability issues. This overview concludes with a discussion of research needs and challenges
facing this evolving field. The biogeochemical processes within the upper few centimeters of sediments beneath nearly all
surface-water bodies (hyporheic zone) have a profound effect on the chemistry of the water interchange, and here is where most of the recent research has been
focusing. However, to advance conceptual and other modeling of GW–SW systems, a broader perspective of such interactions across
and between surface-water bodies is needed, including multidimensional analyses, interface hydraulic characterization and
spatial variability, site-to-region regionalization approaches, as well as cross-disciplinary collaborations.
Electronic Publication 相似文献
7.
Tang Qiuhong Huang Zhongwei Liu Xingcai Han Songjun Leng Guoyong Zhang Xuejun Mu Mengfei 《地球科学进展》2015,30(10):1091-1099
Along with the increase of population and extraordinary economic and social development, human appropriation of freshwater supply increases rapidly. Anthropogenic activities have become an important driving factor of the large-scale terrestrial water cycle. The hydrological effects of human water use have attracted growing attention. In this paper, we briefly reviewed the recent studies addressing the anthropogenic disturbance of the large-scale terrestrial water cycle. The review focused on the direct alteration of the water cycle for human needs, with special coverage for the primary aspects of human water use such as irrigation, domestic and industrial water use, reservoir regulation and groundwater mining. The state-of-the-art parameterization schemes of human water use for macroscale land surface hydrological modeling were introduced and the limitations of the schemes were discussed. Considering the impacts of human water use on the terrestrial water cycle is currently a challenge for macroscale land surface hydrological modeling, which hinders the use of the models in assessing water resources under changing environment. Further studies are needed to understand the interactions between human and water systems, to develop integrated assessment model of coupled human-water systems, and to assess regional and global water security. 相似文献
9.
Mechanically-based numerical modeling is a powerful tool for investigating fundamental processes associated with the formation and evolution of both large and small-scale geologic structures. Such methods are complementary with traditional geometrically-based cross-section analysis tools, as they enable mechanical validation of geometric interpretations. A variety of numerical methods are now widely used, and readily accessible to both expert and novice. We provide an overview of the two main classes of methods used for geologic studies: continuum methods (finite element, finite difference, boundary element), which divide the model into elements to calculate a system of equations to solve for both stress and strain behavior; and particle dynamics methods, which rely on the interactions between discrete particles to define the aggregate behavior of the system. The complex constitutive behaviors, large displacements, and prevalence of discontinuities in geologic systems, pose unique challenges for the modeler. The two classes of methods address these issues differently; e.g., continuum methods allow the user to input prescribed constitutive laws for the modeled materials, whereas the constitutive behavior ‘emerges’ from particle dynamics methods. Sample rheologies, case studies and comparative models are presented to demonstrate the methodologies and opportunities for future modelers. 相似文献
10.
地壳浅层次褶皱冲断带普遍受控于具耦合互馈特性的多种机制或边界条件,从而具有长期的构造演化过程和复杂的构造特征。自19世纪初以来,基于地质构造过程自相似性和"无理有效性"的砂箱物理模型,为解译褶皱冲断带的演化过程及其动力学机制等提供了独立有效的手段。本文主要基于国内外地壳浅表褶皱冲断带构造变形过程为研究对象的构造砂箱物理模型研究结果与进展进行综述性报道,以期为同行提供参考与借鉴。基于与地壳浅表地层具相似流变学特性的砂箱物理模拟研究,揭示出地壳浅层次构造变形过程普遍自相似性生长过程,符合库伦临界楔理论。褶皱冲断带挤压变形过程中,基底特性(基底几何学、有效摩擦角、基底耦合性和流体超压)、变形物质特性(空间几何学、能干层、流变学和非均一性)、动力学机制(砂箱几何边界、汇聚速率和汇聚方向)、浅表作用(剥蚀和沉降)等对于地壳浅表构造变形过程具有明显的控制作用。构造砂箱物理模型在解译不同构造变形过程与机制的研究中发挥着越来越突出的作用。 相似文献
11.
John W. Day Robert R. Christian Donald M. Boesch Alejandro Yáñez-Arancibia James Morris Robert R. Twilley Larissa Naylor Linda Schaffner Court Stevenson 《Estuaries and Coasts》2008,31(3):477-491
Climate impacts on coastal and estuarine systems take many forms and are dependent on the local conditions, including those
set by humans. We use a biocomplexity framework to provide a perspective of the consequences of climate change for coastal
wetland ecogeomorphology. We concentrate on three dimensions of climate change affects on ecogeomorphology: sea level rise,
changes in storm frequency and intensity, and changes in freshwater, sediment, and nutrient inputs. While sea level rise,
storms, sedimentation, and changing freshwater input can directly impact coastal and estuarine wetlands, biological processes
can modify these physical impacts. Geomorphological changes to coastal and estuarine ecosystems can induce complex outcomes
for the biota that are not themselves intuitively obvious because they are mediated by networks of biological interactions.
Human impacts on wetlands occur at all scales. At the global scale, humans are altering climate at rapid rates compared to
the historical and recent geological record. Climate change can disrupt ecological systems if it occurs at characteristic
time scales shorter than ecological system response and causes alterations in ecological function that foster changes in structure
or alter functional interactions. Many coastal wetlands can adjust to predicted climate change, but human impacts, in combination
with climate change, will significantly affect coastal wetland ecosystems. Management for climate change must strike a balance
between that which allows pulsing of materials and energy to the ecosystems and promotes ecosystem goods and services, while
protecting human structures and activities. Science-based management depends on a multi-scale understanding of these biocomplex
wetland systems. Causation is often associated with multiple factors, considerable variability, feedbacks, and interferences.
The impacts of climate change can be detected through monitoring and assessment of historical or geological records. Attribution
can be inferred through these in conjunction with experimentation and modeling. A significant challenge to allow wise management
of coastal wetlands is to develop observing systems that act at appropriate scales to detect global climate change and its
effects in the context of the various local and smaller scale effects. 相似文献
12.
Implication of coupled natural and human systems in sustainable rangeland ecosystem management in HKH region 总被引：1，自引：0，他引：1
The sustainable development of rangeland ecosystems, the vital ecosystems providing many important ecosystem services for
millions of people in the Hindu Kush-Himalaya region is presently confronted with a number of challenges. A coupled natural
and human systems approach is needed to facilitate effective collaboration among social scientists, bio/physical scientists,
and management practitioners to better understand how people interact with the environment in which they live. In pursuing
this argument, three existing case studies, i.e. Indigenous rangeland management in Himalayan Nepal, Cultivated Grassland
Systems in Eastern Qinghai-Tibetan Plateau, and Grassland Restoration in Central Qinghai-Tibetan Plateau were synthesized
in this paper to address the importance of coupled natural and human systems in promoting sustainable rangeland ecosystem
management in the Hindu Kush-Himalaya (HKH) region. It was concluded although the research sites and objectives were very
different, that these three case studies had many commonalities that addressed the complex interactions and feedbacks between
natural and human systems, and highlighted the integration of various tools and techniques from the ecological and social
sciences, as well as other disciplines, in sustainable rangeland management. These case studies have offered unique interdisciplinary
insights into complexities that cannot be gained from ecological or social research alone. The results from these case studies
can be applied to many other coupled systems at local, national, and global levels. 相似文献
13.
Discrete-element, individual-based and agent-based modelling techniques represent the interactions of individuals or entities with one another and their environments by sets of computational rules. These methods are now being used in geophysics, ecology, zoology, and increasingly in the social sciences. A characteristic is that the “agents” are embedded in an environment with which they interact, so that joint evolution of physical, ecological and socio-economic systems can be studied; this makes them of interest in integrated geographical investigation. Of particular interest is the fact that they allow the study of macro-scale emergent behaviour generated by multiple individual actions. Discrete techniques have the potential to create integrated models that cross disciplines. Similar computational methods can be employed to control the spatial search process, deal with irregular or changing boundaries, and to track the evolution of systems where preservation of heterogeneity across space and time is important. The complex series of feedbacks between the different types of system can thus be modelled within a single computational framework. Humans modelled in this way as “agents” can allow the collective effect of many interacting individuals to generate emergent structures at the community scale. The structural characteristics of their social and natural environments will influence their behaviour, while at the same time constituting emergent consequences of their actions. The principal challenge of the latter is to find those sets of rules that represent the beliefs and desires of real human agents, accurately reflecting the cultural context, while allowing us to explore the social and economic limitations of agents to take action. This paper reviews and illustrates discrete methods applicable to a range of geographical enquiries, and with particular reference to individual- and agent-based methods, assesses the rich diversity of approaches that must be combined to take full advantage of their potential to explore interactions of social and environmental processes. 相似文献
14.
Models of natural and human dynamics in forest landscapes: Cross-site and cross-cultural synthesis 总被引：1，自引：0，他引：1
Miguel F. Acevedo J. Baird Callicott Donald Lyons Judith Rosales Magdiel Ablan Giorgio Tonella Emilio Vilanova 《Geoforum》2008,39(2):846-866
We synthesize the study of coupled natural and human systems across sites and cultures through a process of simplification and abstraction based on multiple dimensions of human-nature connectedness: satisfaction of basic needs, psycho-cultural connectedness and regulation of use of natural resources. We thus provide both a place-based and general understanding of value-driven anthropogenic environmental change and response. Two questions guide this research: what are the crucial stakeholder values that drive land use decisions and thus land cover change? And how can knowledge of these values be used to make decisions and policies that sustain both the human and natural systems in a place? To explore these questions we build simulation models of four study sites, two in the State of Texas, United States, and two in Venezuela. All include protected areas, though they differ in the specifics of vegetation and land use. In the Texas sites, relatively affluent individuals are legally converting forests to residential, commercial, and industrial uses, while in Venezuela landless settlers are extra-legally converting forests for purposes of subsistence agriculture. Contemporary modeling techniques now facilitate simulations of stakeholder and ecosystem dynamics revealing emergent patterns. Such coupled human and natural systems are currently recognized as a form of biocomplexity. Our modeling framework is flexible enough to allow adaptation to each of the study sites, capturing the essential features of the respective natural and anthropogenic land use changes and stakeholder reactions. The interactions between human stakeholders are simulated using multi-agent models that act on forest landscape models, and receive feedback of the effects of these actions on ecological habitats and hydrological response. The multi-agent models employ a formal logic-based method for the Venezuelan sites and a decision analysis approach using multi-attribute utility functions for the Texas sites, differing more in style and emphasis than in substance. Our natural-systems models are generic and can be tailored according to site-specific conditions. Similar models of tree growth and patch transitions are used for all the study sites and the differing responses to environmental variables are specified for each local species and terrain conditions. 相似文献
15.
半干旱区景观格局与生态水文过程研究进展 总被引：7，自引：2，他引：5
景观格局和生态水文过程之间具有紧密的联系和相互作用,在半干旱地区这种联系尤为显著,是地球科学研究的重要前沿领域.尺度效应在两者关系中起重要作用,不同尺度下两者相互作用机制有很大差异.归纳总结了半干旱地区景观格局与生态水文过程的研究现状与进展,包括二者相互作用机理、影响因素、干扰、尤其是人为干扰对这种相互作用的影响,以及模型模拟等.以尺度为线索,在斑块、坡面和流域尺度进行展开.最后,提出了半干旱地区景观格局与生态水文过程研究中存在的问题、热点和趋势,包括物理机制、干扰后的恢复机制、模型发展、流域尺度集成及尺度转换. 相似文献
16.
Marc Walther Lars Bilke Jens-Olaf Delfs Thomas Graf Jens Grundmann Olaf Kolditz Rudolf Liedl 《Environmental Earth Sciences》2014,72(10):3827-3837
This paper evaluates the remediation potential of a salinized coastal aquifer by utilizing a scenario simulation. Therefore, the numerical model OpenGeoSys is first validated against analytical and experimental data to represent transient groundwater level development and variable density saline intrusion. Afterwards, a regional scale model with a three-dimensional, heterogeneous hydrogeology is calibrated for a transient state and used to simulate a best-case scenario. Water balances are evaluated in both the transient calibration and scenario run. Visualization techniques help to assess the complex model output providing valuable insight in the occurring density-driven flow processes. Furthermore, modeling and visualization results give information on the time scale for remediation activities and, due to limitations in data quality and quantity reveal potential for model improvement. 相似文献
17.
城市洪涝模拟是当前国内外城市防洪减灾领域研究的热点。现有城市洪涝模拟方面的评述,主要依据城市洪涝过程或模拟计算方法进行分类讨论,缺乏基于应用需求的视角。随着应用需求日益深入,城市洪涝模拟应用场景日趋多样化和复杂化,不同模拟应用场景下,所关注的洪涝过程不同,采用的技术策略及其重点和难点也不同,脱离模拟应用场景很难辨析这些不同。依据模拟对象和关注变量,归纳总结出城市洪涝模拟的3种典型应用场景,即城市外洪模拟、城市雨洪模拟、城市内涝模拟;针对这3种典型模拟应用场景,分析相应的城市洪水演进模型、城市雨洪模型、半分布式暴雨内涝模型、全分布式暴雨内涝模型等4类模拟技术策略;辨析在不同模拟应用场景和技术策略下,不同模拟技术的组合方式及其特点与难点,以期从应用需求的角度对城市洪涝模拟技术进行全面的梳理,为城市洪涝模拟应用和研究提供一个新的视角。 相似文献
18.
Yifeng Cui Reagan Moore Kim Olsen Amit Chourasia Philip Maechling Bernard Minster Steven Day Yuanfang Hu Jing Zhu Thomas Jordan 《Acta Geotechnica》2009,4(2):79-93
Earthquakes are among the most complex terrestrial phenomena, and modeling of earthquake dynamics is one of the most challenging
computational problems in science. Computational capabilities have advanced to a state where we can perform wavefield simulations
for realistic three-dimensional earth models, and gain more insights into the earthquakes that threaten California and many
areas of the world. The Southern California Earthquake Center initiated a major earthquake research program called TeraShake
to perform physics-based numerical simulations of earthquake processes for large geographical regions, at high resolution,
and for high frequencies. For a large scale simulation such as TeraShake, optimization problems tend to emerge that are not
significant in smaller scale simulations. This involves both large parallel computation and also massive data management and
visualization coordination. In this paper, we describe how we performed single-processor optimization of the TeraShake AWM
application, optimization of the I/O handling, and optimization of initialization. We also look at the challenges presented
by run-time data archive management and visualization. The improvements made to the TeraShake AWM code enabled execution on
the 40k IBM Blue Gene processors and have created a community code that can be used by seismologists to perform petascale
earthquake simulations. 相似文献
19.
The state of the art of modeling fluid flow in shale reservoirs is dominated by dual-porosity models which divide the reservoirs into matrix blocks that significantly contribute to fluid storage and fracture networks which principally control flow capacity. However, recent extensive microscopic studies reveal that there exist massive micro- and nano-pore systems in shale matrices. Because of this, the actual flow mechanisms in shale reservoirs are considerably more complex than can be simulated by the conventional dual-porosity models and Darcy’s law. Therefore, a model capturing multiple pore scales and flow can provide a better understanding of the complex flow mechanisms occurring in these reservoirs. This paper presents a micro-scale multiple-porosity model for fluid flow in shale reservoirs by capturing the dynamics occurring in three porosity systems: inorganic matter, organic matter (mainly kerogen), and natural fractures. Inorganic and organic portions of shale matrix are treated as sub-blocks with different attributes, such as wettability and pore structures. In kerogen, gas desorption and diffusion are the dominant physics. Since the flow regimes are sensitive to pore size, the effects of nano-pores and micro-pores in kerogen are incorporated into the simulator. The multiple-porosity model is built upon a unique tool for simulating general multiple-porosity systems in which several porosity systems may be tied to each other through arbitrary connectivities. This new model allows us to better understand complex flow mechanisms and eventually is extended into the reservoir scale through upscaling techniques. Sensitivity studies on the contributions of the different flow mechanisms and kerogen properties give some insight as to their importance. Results also include a comparison of the conventional dual-porosity treatment and show that significant differences in fluid distributions and dynamics are obtained with the improved multiple-porosity simulation. 相似文献
20.
This paper presents an integrated effort of a long-term risk analysis for the emergency response of nuclear power plants in
complex terrains. Use of coupled source term, fate and transport, and exposure assessment models associated with eight synoptic
weather patterns successfully provides timely and reasonably accurate long-range prognostic wind fields to simulate the possible
exposure episodes and risk potential. The seamless integration of multi-scale simulation models in accordance with different
release scenarios of process source term in the nuclear power plants permits the simulation of pollutant fate, transport,
and deposition processes in multiple dimensions of atmospheric environment. With the aid of spatial analysis, the assessment
of potential detrimental impacts for the accidental release of various nuclides from nuclear power plants becomes achievable.
The practical implementation of this integrated modeling system was assessed by case studies at one existing nuclear power
plant in southern Taiwan, China. Two- and three-dimensional fly-through visualization technologies make risk assessment practical
and credible based on the differing weather patterns identified at the continental scale in advance. 相似文献