Scenario analysis: a review of methods and applications for engineering and environmental systems

Changing environment, uncertain economic conditions, and socio-political unrest have renewed interest in scenario analysis, both from theoretical and applied points of view. Nevertheless, neither the processes for scenario analysis (SA) nor evaluation criteria and metrics have been regularized. In this paper, SA-reported applications and implementation methodology are discussed in the context of an extensive literature review covering papers published between 2000 and 2010. Over 340 papers were identified through a series of queries in the web of science database. The papers were classified based on the North American Industrial Classification System and SA application goals (environmental, business, and social). SA methodology used in each paper was assessed based on four main criteria: coverage, consistency, uncertainty assessment, and efficiency. We find a significant increase in SA applications, especially in the environmental field. Theoretical developments in the field represent a small fraction of published studies and do not increase in time. The methods used to develop different scenarios vary widely across the academic literature and applications reviewed. Similarly, the methods and data used to characterize the scenarios and develop response strategies are extremely diverse and are limited by factors such as computational tractability and available time and resources. Based on this review, we recommend a regular process for scenario analysis that includes the steps of analysis, scenario definition, and evaluation.     

Environmental Indicators of Biofuel Sustainability: What About Context?

Indicators of the environmental sustainability of biofuel production, distribution, and use should be selected, measured, and interpreted with respect to the context in which they are used. The context of a sustainability assessment includes the purpose, the particular biofuel production and distribution system, policy conditions, stakeholder values, location, temporal influences, spatial scale, baselines, and reference scenarios. We recommend that biofuel sustainability questions be formulated with respect to the context, that appropriate indicators of environmental sustainability be developed or selected from more generic suites, and that decision makers consider context in ascribing meaning to indicators. In addition, considerations such as technical objectives, varying values and perspectives of stakeholder groups, indicator cost, and availability and reliability of data need to be understood and considered. Sustainability indicators for biofuels are most useful if adequate historical data are available, information can be collected at appropriate spatial and temporal scales, organizations are committed to use indicator information in the decision-making process, and indicators can effectively guide behavior toward more sustainable practices.     

Visiting a Climate-Influenced National Park: The Stability of Climate Change Perceptions

Understanding perceptions of global environmental issues, such as climate change, can help inform resource management, policy development, and communication with constituents. Although a considerable amount of research documents citizens’ perceptions of climate change, few have investigated how interactions with climate-impacted parks and protected areas influence these perceptions, and consequently elements of environmental management. Using a mixed methods Instrument Development Approach, the researchers examined the stability of park visitors’ (N = 429) climate change perceptions during a daylong interaction with climate-sensitive and influenced resources at Kenai Fjords National Park in Alaska. Results indicate that global-level beliefs about climate change remained relatively stable during a park experience, but perceptions about climate change at the park-level (e.g., impacts) appeared more malleable. Findings also revealed the type of park experience (terrestrial vs. marine) can influence the degree of change in visitors’ perceptions. Implications for communication, outreach, and park management are discussed.     

The Impact of Asynchronicity on Event‐Flow Estimation in Basin‐Scale Hydrologic Model Calibration1

Abstract: The calibration of basin‐scale hydrologic models consists of adjusting parameters such that simulated values closely match observed values. However, due to inevitable inaccuracies in models and model inputs, simulated response hydrographs for multiyear calibrations will not be perfectly synchronized with observed response hydrographs at the daily time step. An analytically derived formula suggests that when timing errors are significant, traditional calibration approaches may generally underestimate the total event‐flow volume. An event‐adaptive time series is developed and incorporated into the Nash‐Sutcliffe Efficiency objective function to diagnose the potential impact of event‐flow synchronization errors. Test sites are the 50 km² Subwatershed I of the Little River Experimental Watershed (LREWswI) in southeastern Georgia, and the 610 km² Little Washita River Experimental Watershed (LWREW) in southwestern Oklahoma, with the Soil and Water Assessment Tool used as the hydrologic model. Results suggest that simulated surface runoff generation is 55% less for LREWswI when the daily time series is used compared with when the event‐adaptive technique is used. Event‐flow generation may also be underestimated for LWREW, but to a lesser extent than it may be for LREWswI, due to a larger portion of the event flow being lateral flow.     

粉煤灰制备含硫絮凝剂的研究进展

介绍了粉煤灰的来源、数量、危害、主要成分及性质,简介了粉煤灰的综合利用情况;综述了以粉煤灰为主要原料制备含硫絮凝剂的工艺、方法等研究现状和在水处理中的应用效果;分析了该类絮凝剂处理污水的机理;对进一步有效开发利用粉煤灰提出了建议。     

基于心理感知的铁路综合客运枢纽客流疏解预警研究*

为解决铁路综合客运枢纽客流疏解预警忽略旅客心理感知与焦虑问题,基于状态焦虑问卷,定量描述旅客焦虑状态,通过引入心理测量学中积极率划分客流疏解等级阈值,确定枢纽客流疏解预警等级,构建以旅客感知疏解时间为预警指标的回归预测模型。研究结果表明:模型可定量预测枢纽站各种交通接驳方式客流的感知疏解时间,准确描述枢纽站预警等级,研究结果可为管理人员选择相应疏解措施提供依据。     

Unintended nutrient imbalance induced by wastewater effluent inputs to receiving water and its ecological consequences

Eutrophication is the most widespread water quality issue globally. To date, most efforts to control eutrophication have focused on reductions of external nutrient inputs, yet importance of nutrient stoichiometry and subsequent shift in plankton composition in aquatic ecosystem has been largely neglected. To address eutrophication, improved sanitation is one of the United Nations Sustainable Development Goals, spurring the constructions of wastewater treatment facilities that have improved water quality in many lakes and rivers. However, control measures are often targeted at and effective in removing a single nutrient from sewage and thus are less effective in removing the others, resulting in the changes of nutrient stoichiometry. In general, more effective phosphorus removal relative to nitrogen has occurred in wastewater treatment leading to substantial increases in N/P ratios in effluent relative to the influent. Unfortunately, high N/P ratios in receiving waters can impose negative influences on ecosystems. Thus, long-term strategies for domestic wastewater management should not merely focus on the total reduction of nutrient discharge but also consider their stoichiometric balances in receiving waters.     

Modeling health impacts of air pollutant emissions from the coal-fired power industry based on LCA and oriented by WTP: a case study

Environmental Science and Pollution Research - Coal-fired power plants are one of the major sources of coal consumption in China; they discharge various air pollutants and cause serious human...     

β-六溴环十二烷对玉米生长代谢的对映体选择性影响

为了探讨不同光旋纯活性的β-HBCD对植物生长代谢的对映体选择性影响,本研究采用高效液相色谱法(HPLC)优化分离并制备得到β-六溴环十二烷(β-HBCD)单一对映体((+)β-HBCD和(-)β-HBCD),开展了不同浓度梯度的(+)、(rac)和(-)β-HBCD溶液对玉米幼苗的水培暴露实验.随着β-HBCD暴露浓...