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31.
Governance failures are at the origin of many resource management problems. In particular climate change and the concomitant increase of extreme weather events has exposed the inability of current governance regimes to deal with present and future challenges. Still our knowledge about resource governance regimes and how they change is quite limited. This paper develops a conceptual framework addressing the dynamics and adaptive capacity of resource governance regimes as multi-level learning processes. The influence of formal and informal institutions, the role of state and non-state actors, the nature of multi-level interactions and the relative importance of bureaucratic hierarchies, markets and networks are identified as major structural characteristics of governance regimes. Change is conceptualized as social and societal learning that proceeds in a stepwise fashion moving from single to double to triple loop learning. Informal networks are considered to play a crucial role in such learning processes. The framework supports flexible and context sensitive analysis without being case study specific.First empirical evidence from water governance supports the assumptions made on the dynamics of governance regimes and the usefulness of the chosen approach. More complex and diverse governance regimes have a higher adaptive capacity. However, it is still an open question how to overcome the state of single-loop learning that seem to characterize many attempts to adapt to climate change. Only further development and application of shared conceptual frameworks taking into account the real complexity of governance regimes can generate the knowledge base needed to advance current understanding to a state that allows giving meaningful policy advice.  相似文献   
32.
Greater recognition of the seriousness of global environmental change has led to an increase in research that assesses the vulnerability of households, communities and regions to changing environmental or economic conditions. So far, however, there has been relatively little attention given to how assessments can be conducted in ways that help build capacity for local communities to understand and find their own solutions to their problems. This paper reports on an approach that was designed and used to work with a local grass roots organization in the Solomon Islands to promote inclusivity and participation in decision-making and to build the capacity of the organization to reduce the vulnerability of communities to drivers of change. The process involved working collaboratively with the organization and training its members to conduct vulnerability assessments with communities using participatory and deliberative methods. To make best use of the learning opportunities provided by the research process, specific periods for formal reflection were incorporated for the three key stakeholders involved: the primary researchers; research assistants; and community members. Overall, the approach: (1) promoted learning about the current situation in Kahua and encouraged deeper analysis of problems; (2) built capacity for communities to manage the challenges they were facing; and (3) fostered local ownership and responsibility for problems and set precedents for future participation in decision-making. While the local organization and the communities it serves still face significant challenges, the research approach set the scene for greater local participation and effort to maintain and enhance livelihoods and wellbeing. The outcomes highlight the need for greater emphasis on embedding participatory approaches in vulnerability assessments for communities to benefit fully from the process.  相似文献   
33.
Adaptive co-management and the paradox of learning   总被引:10,自引:1,他引:9  
Much emphasis has been placed on the importance of learning to support collaborative environmental management and achieve sustainability under conditions of social–ecological change. Yet, on-going struggles to learn from experience and respond to complex social–ecological conditions reflect an emerging paradox. Despite widespread support of learning as a normative goal and process, core concepts, assumptions and approaches to learning have been applied in vague and sometimes uncritical ways. Greater specificity with respect to learning goals, approaches and outcomes is required. In response to this gap, we examine five dimensions of the learning paradox in the context of adaptive co-management, where the learning and linking functions of governance are stressed: (i) definitions of learning; (ii) learning goals and expectations; (iii) mechanisms by which learning takes place; (iv) questions regarding who is involved in the process of learning; and (v) the risks and ethical ambiguities faced by different actors expected to willingly participate in a learning process, whether formal or informal. Lessons from experience with a series of cases from the global North and South illustrate the implications of these dimensions. Resolving the dimensions of this learning paradox will require greater attention to capacity-building, recognition of the role of risk, and consideration of how incentives could be used to encourage learning. Further consideration of the role of power and marginality among groups participating in the learning process is also needed, as is more systematic evaluation to monitor and measure learning outcomes.  相似文献   
34.
An increasing number of publications focus on social vulnerability, resilience, and adaptation (SVRA) towards natural hazards and climate change. Despite this proliferation of research, a systematic understanding of how these studies are theoretically grounded is lacking. Here, we systematically reviewed 4432 articles that address SVRA in various disciplinary fields (e.g. psychology, sociology, geography, mathematics) for various hazards, including floods, droughts, landslides, storm surges, wildfires, tsunamis, earthquakes, and volcano eruptions. We focus on the extent to which these studies explicate the frameworks, theoretical constructs or theories they rely on. Surprisingly, we found that about 90% of the reviewed studies do not explicitly refer to a theoretical underpinning. Overall, theories focusing on individuals’ SVRA were more frequently used than those focusing on systems, society, groups, and networks. Moreover, the uptake of theories varied according to the hazard investigated and field of knowledge, being more frequent in wildfire and flood studies and articles published in social science journals. Based on our analysis, we propose a reflexive handling of theories to foster more transparent, comparable, and robust empirical research on SVRA.  相似文献   
35.
利用传统有限差分方法对基于Biot理论的双相介质波动方程进行数值求解时,由于慢纵波的存在,数值频散效应较为明显,影响模拟精度.相对于声学近似方程及普通弹性波方程,Biot双相介质波动方程在同等数值求解算法和精度要求条件下,其地震波场正演模拟需要更多的计算时间.本文针对Biot一阶速度-应力方程组发展了一种变阶数优化有限差分数值模拟方法,旨在同时提高其正演模拟的精度和效率.首先结合交错网格差分格式推导Biot方程的数值频散关系式.然后基于Remez迭代算法求取一阶空间偏导数的优化差分系数,并用于Biot方程的交错网格有限差分数值模拟.在此基础上把三类波的平均频散误差参数限制在给定的频散误差阈值和频率范围内,此时优化有限差分算子的长度就能自适应非均匀双相介质模型中的不同速度区间.数值频散曲线分析表明:基于Remez迭代算法的优化有限差分方法相较传统泰勒级数展开方法在大波数范围对频散误差的压制效果更明显;可变阶数的优化有限差分方法能取得与固定阶数优化有限差分方法相近的模拟精度.在均匀介质和河道模型的数值模拟实验中将本文变阶数优化有限差分算法与传统泰勒展开算法、最小二乘优化算法进行比较,进一步证明其在复杂地下介质中的有效性和适用性.  相似文献   
36.
地震数据中发育的层间多次波是影响速度分析和偏移成像的精度和可靠性的关键.通常情况下,层间多次波的动校正量、叠加速度和频率与一次波并无明显差异,从而对识别、预测和压制多次波带来了极大挑战.传统虚同相轴方法基于物理图像和定性公式,其预测的层间多次波振幅和相位精度难以满足实际需求,造成了其对匹配算法的过度依赖.本文针对传统虚同相轴方法的理论缺陷和计算精度问题,通过理论推导得到了新的自适应虚同相轴方法.相比于传统方法,自适应虚同相轴方法能够显著提高压制多次波能力,同时减少对匹配算法的依赖.本文给出了自适应虚同相轴方法的推导过程,并运用一维和二维模型算例验证了方法相较于传统虚同相轴方法的多次波预测精度优势.通过在PLUTO模型和实际陆地地震数据上的应用实例,证明了本文新研究的自适应虚同相轴方法对去除层间多次波,恢复并突出目标储层同相轴,提高地震成像分辨率的显著作用.  相似文献   
37.
沈莎莎  陈爽  高群  张殷俊 《湖泊科学》2013,25(2):309-316
江苏省环太湖地区快速城市化和工业化加剧饮用水危机,整合研究水源地、供水、用水、排污处理和技术5个方面对于支撑该地区可持续发展的适应能力,对揭示饮用水供需关系、存在问题、部门协调与综合决策等具有现实意义.本文以构建5个子系统适应能力指标体系为主线,通过分指数与综合指数评价的运算,得出研究地区饮用水系统适应能力等级水平、地域分异特征及影响因素分析;针对各子系统存在问题,提出维护和提升适应能力的对策措施.研究表明,适应能力较强的地区占总面积29.1%,其5个子系统适应能力均较强.适应能力中等地区占41.2%,一类是各子系统适应能力基本均等,另一类是排污处理子系统适应能力较强,但用水子系统得分较低.适应能力较差地区占29.7%,主要是技术子系统分值低,其它子系统适应能力处于中等偏下.因此需加大对各子系统适应能力的调控与提升.  相似文献   
38.
经验模态分解算法(EMD)是一种基于有效波和噪声尺度差异进行波场分离的随机噪声压制方法,但由于实际地震数据波场复杂,导致模态混叠较严重,仅凭该方法进行去噪很难达到理想效果.本文基于EMD算法对信号多尺度的分解特性,结合Hausdorff维数约束条件,提出一种用于地震随机噪声衰减的新方法.首先对地震数据进行EMD自适应分解,得到一系列具有不同尺度的、分形自相似性的固有模态分量(IMF);在此基础上,基于有效信号和随机噪声的Hausdorff维数差异,识别混有随机噪声的IMF分量,对该分量进行相关的阈值滤波处理,从而实现有效信号和随机噪声的有效分离.文中从仿真信号试验出发,到模型地震数据和实际地震数据的测试处理,同时与传统的EMD处理结果相对比.结果表明,本文方法对地震随机噪声的衰减有更佳的压制效果.  相似文献   
39.
在浅水情况下,由于观测数据中缺少近偏移距信息,水层多次波的压制面临挑战.利用多道预测算子压制水层多次波是浅水环境下压制多次波的重要方法之一,这种方法先从输入数据中估计出多道预测算子,再将预测算子和输入数据做褶积预测出水层相关多次波.然而,估计的多道预测算子很容易受噪声污染,从而影响多次波模型的精度.所以,我们提出了改进的多道预测算子压制浅水多次波方法.该方法先从数据中估计出多道预测算子,并利用估计的算子构建出精确的水层模型;然后,通过计算算子的走时信息、估计振幅信息、合成新算子三个步骤来修正原始的多道预测算子.修正的算子不仅不受噪声影响,还含有精确的走时信息、可靠的振幅信息;最后,该方法用修正的算子来预测多次波,并结合自适应相减,将预测的多次波从输入数据中去除.通过合成数据和实际资料的验证表明,相比于原始的多道预测算子压制多次波方法,改进的方法能够取得更好的压制效果.  相似文献   
40.
Longkou City is a coastal area,and lacks water resources.The overexploitation of groundwater causes seawater intrusion.At present,seawater intrudes an area of 68 km2.With the decrease of groundwater extraction,the seawater intrusion area has generally declined.The paper expounds the development process of seawater intrusion as well as the corresponding prevention and control measures of using groundwater replenishment and groundwater throttling in Longkou City.In view of the seawater intrusion problem in Longkou City,some adaptive management countermeasures are put forward,which include:Adjusting industrial and agricultural structure,promoting economic and social development to match water resources;improving water usage structure,optimizing the utilization of water resources;advancing the construction of a water-saving society,using water resources efficiently;implementing inter-basin water transfer,using water resources rationally;developing and utilizing unconventional water sources,making full use of water resources;strengthening water infrastructure construction,increasing the development and utilization potential of water resources;carrying out ecological restoration,protecting water resources and ecological environment;improving the management informationalization level,strengthening the capabilities of groundwater monitoring and management;increasing publicity,improving public awareness of participation.  相似文献   
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