System Dynamics to Sustainable Water Resources Management in the Eastern Snake Plain Aquifer Under Water Supply Uncertainty1

Abstract: Water supply uncertainty continues to threaten the reliability of regional water resources in the western United States. Climate variability and water dispute potentials induce water managers to develop proactive adaptive management strategies to mitigate future hydroclimate impacts. The Eastern Snake Plain Aquifer in the state of Idaho is also facing these challenges in the sense that population growth and economic development strongly depend on reliable water resources from underground storage. Drought and subsequent water conflict often drive scientific research and political agendas because water resources availability and aquifer management for a sustainable rural economy are of great interest. In this study, a system dynamics approach is applied to address dynamically complex problems with management of the aquifer and associated surface‐water and groundwater interactions. Recharge and discharge dynamics within the aquifer system are coded in an environmental modeling framework to identify long‐term behavior of aquifer responses to uncertain future hydrological variability. The research shows that the system dynamics approach is a promising modeling tool to develop sustainable water resources planning and management in a collaborative decision‐making framework and also to provide useful insights and alternative opportunities for operational management, policy support, and participatory strategic planning to mitigate future hydroclimate impacts in human dimensions.     

我国农村劳动力流动性就业计量问题研究

改革开放30年来,上亿农村劳动力实现了向城镇非农产业大规模转移,而我国沿袭至今的劳动就业统计制度突出的缺陷是将三部分人--在农村从事纯农的农民,在城镇从事非农工作但户口在农村的农民工,游移于乡城间"亦工亦农"的农村劳动力--排除于劳动统计计量之外.不解决这部分劳动力就业的统计计量的问题,则很难准确回答"中国的失业率究竟有多高?".为此,确定严格的、便于与国际接轨的劳动就业标准,从而构建我国统一的、规范的劳动就业市场至关重要.本文着重探讨了游移于农村与城市之间、就业岗位、就业时间不固定的农村劳动力就业、失业不充分的计量问题.作者在对国内外就业和失业定义和计量标准进行比较和评价基础上,结合我国实情提出了以法定劳动力年工时为核心的劳动力流动性就业的调查和计量方法,并通过调查案例证实了它的有效性与可行性.     

Effects of input uncertainty and variability on the modelled environmental fate of organic pollutants under global climate change scenarios

Global climate change (GCC) is expected to influence the fate, exposure and risks of organic pollutants to wildlife and humans. Multimedia chemical fate models have been previously applied to estimate how GCC affects pollutant concentrations in the environment and biota, but previous studies have not addressed how uncertainty and variability of model inputs affect model predictions. Here, we assess the influence of climate variability and chemical property uncertainty on future projections of environmental fate of six polychlorinated biphenyl congeners under different GCC scenarios using a spreadsheet version of the ChemCAN model and the Crystal Ball® software. Regardless of emission mode, results demonstrate: (i) uncertainty in degradation half-lives dominates the variance of modelled absolute levels of PCB congeners under GCC scenarios; (ii) when the ratios of predictions under GCC to predictions under present day climate are modelled, climate variability dominates the variance of modelled ratios; and (iii) the ratios also indicate a maximum of about a factor of 2 change in the long-term average environmental concentrations due to GCC that is forecasted between present conditions and the period between 2080 and 2099. We conclude that chemical property uncertainty does not preclude assessing relative changes in a GCC scenario compared to a present-day scenario if variance in model outputs due to chemical properties and degradation half-lives can be assumed to cancel out in the two scenarios.     

基于层次分析法的未确知测度理论泥石流危险性评价

将未确知测度理论与层次分析方法相结合用于评价泥石流危险性。根据泥石流危险性的影响因素和等级划分标准,选取泥石流规模、泥石流发生频率、流域面积、主沟长度、最大相对高差、流域切割密度、主沟床弯曲系数、泥砂补给长度比、24小时最大降雨量、人口密度等10个指标作为泥石流危险评价因子,利用未确知测度理论建立泥石流危险性评价指标的未确知测度函数,通过层次分析方法确定各评价指标的权重,依据置信度识别准则对泥石流危险性进行评价,并结合实例进行了对比分析。研究结果表明,基于层次分析方法的未确知测度理论的评价方法评价过程合理、置信度高、结果可靠,为泥石流危险性评价提供了一种新的方法     

土地利用规划中不确定性的识别和处理研究

首先概述不确定性概念及其产生、相关理论和研究进展,深刻地揭示由于在我国土地和用规划中长期以来忽视开展不确定性研究,导致规划指标偏离现实需求,频繁修改规划方案和违法用地现象不断发生,在此基础上,引入不确定性规划理念,重新审视不确定性在土地利用规划中的地位和作用,全面系统地阐述土地利用规划中不确定性的类型及其特性,具体表现及其识别和处理方法.研究结果表明,由于人们的知识所限,客观世界中普遍存在不确定性.不确定性孕育着规划的产生,规划是对未来不确定性的缓解和抵消.土地利用规划中长期以来忽视业已存在的不确定性,直接影响土地利用规划的科学性和可操作性.土地利用规划中最基本的不确定性是预测未来和为了适应未来而对现在进行调整的失误.对未来的无知所引发的不确定性,只能求助于不确定性科学,增强对未来的预测能力和控制能力,使不确定性的负面影响最小化.     

Distribution and transport characteristics of fine particulate matter in beijing with mobile lidar measurements from 2015 to 2018

Accurately quantifying the concentration and transport flux of atmospheric fine particulate matter(PM_2.5) is vital when attempting to thoroughly identify the pollution formation mechanism.In this study,the mobile lidar measurements in Beijing on heavily polluted days in December from 2015 to 2018 are presented.The lidar was mounted on a vehicle,which could perform measurements along designated routes.On the basis of mobile lidar measurements along closed circuits of the 6 th Ring Road...     

Testing the feasibility of a hypothetical whaling‐conservation permit market in Norway

A cap‐and‐trade system for managing whale harvests represents a potentially useful approach to resolve the current gridlock in international whale management. The establishment of whale permit markets, open to both whalers and conservationists, could reveal the strength of conservation demand, about which little is known. This lack of knowledge makes it difficult to predict the outcome of a hypothetical whale permit market. We developed a bioeconomic model to evaluate the influence of economic uncertainty about demand for whale conservation or harvest. We used simulations over a wide range of parameterizations of whaling and conservation demands to examine the potential ecological consequences of the establishment of a whale permit market in Norwegian waters under bounded (but substantial) economic uncertainty. Uncertainty variables were slope of whaling and conservation demand, participation level of conservationists and their willingness to pay for whale conservation, and functional forms of demand, including linear, quadratic, and log‐linear forms. A whale‐conservation market had the potential to yield a wide range of conservation and harvest outcomes, the most likely outcomes were those in which conservationists bought all whale permits.     

气候试验箱内部条件不确定度计算(下)

提供了对温度和湿度气候试验箱内部环境条件进行不确定度分析的方法。首先介绍了测量的不确定度概念,然后讨论容差的意义。考虑到湿度和温度测量是采用确定和合成不确定度。结合校准空载试验箱和有负载试验箱的条件测量的案例。最后,逐条整理成为范本用于分析结果以给出规范的不确定度评估依据。     

Assessing and testing prediction uncertainty for single tree-based models: A case study applied to northern hardwood stands in southern Québec, Canada

Estimating prediction uncertainty for a single tree-based model is hindered by the complex structure of these models. In this paper, we addressed this issue with a case study applied to northern hardwood stands in Québec, Canada. SaMARE is a stochastic single tree-based model that was designed for these types of stands. Using a Monte Carlo approach, the model can provide a mean predicted value and its confidence limits for some plot-level attributes.The mean predicted values were compared to observed values in terms of bias and accuracy. In addition to these common statistics, we compared nominal coverage of Monte Carlo-simulated confidence intervals with real (observed) coverage to verify the adequacy of the simulated uncertainty. A comparison was made using several plot-level attributes, which exhibited an increasing discriminative complexity. This complexity ranges from coarse attributes, such as all-species basal area, up to more complex ones, such as basal area for stems of a particular species and with sawlog potential.The results showed that in terms of absolute value, biases were small, but could be relatively high with respect to the average observed value when the discriminative complexity of the attribute increased. The comparison between nominal and real coverage of confidence intervals gave satisfactory results for all-species plot-level attributes. However, for some species-specific attributes, the Monte Carlo-simulated confidence intervals overestimated the real coverage.     

A NEW LOOK AT FLOOD RISK DETERMINATION1

ABSTRACT: The probability distributions of annual peak flows used in flood risk analysis quantify the risk that a design flood will be exceeded. But the parameters of these distributions are themselves to a degree uncertain and this uncertainty increases the risk that the flood protection provided will in fact prove to be inadequate. The increase in flood risk due to parameter uncertainty is small when a fairly long record of data is available and the annual flood peaks are serially independent, which is the standard assumption in flood frequency analysis. But standard tests for serial independence are insensitive to the type of grouping of high and low values in a time series, which is measured by the Hurst coefficient. This grouping increases the parameter uncertainty considerably. A study of 49 annual peak flow series for Canadian rivers shows that many have a high Hurst coefficient. The corresponding increase in flood risk due to parameter uncertainty is shown to be substantial even for rivers with a long record, and therefore should not be neglected. The paper presents a method of rationally combining parameter uncertainty due to serial correlation, and the stochastic variability of peak flows in a single risk assessment. In addition, a relatively simple time series model that is capable of reproducing the observed serial correlation of flood peaks is presented.