Evaluating response surface designs for uncertainty analysis and prescriptive applications of a large-scale water quality model

Environmental models are often too large and cumbersome for effective use in regulatory decision making or in the characterization of uncertainty. This paper describes and compares four response surfaces that could complement a large-scale water quality model, the U.S. National Water Pollution Control Assessment Model (NWPCAM), in simulation and regulatory decision support applications. Results show that a physically based reduced-form model that exploits the mathematical structure of the underlying water quality model is a better predictor of policy-relevant outputs than the polynomial expansions that are frequently used in response surface studies.     

中国区域生态效率的时空演变及空间互动特征

现有研究主要关注生态效率的测算,对生态效率的空间互动特征缺乏相应地分析。采用考虑非期望产出的SBM模型对中国30个省级行政区2005—2015年生态效率进行测度,并在此基础上利用空间自回归模型考察中国区域生态效率的空间互动特征。结果表明：（1）中国高生态效率区主要分布在沿海发达省份,而低效率区则主要分布在欠发达省份。（2）在全国层面,基于经济权重矩阵得到的空间自回归系数为正且显著,表明区域生态效率存在正向的空间互动效应。（3）分样本估计中,发达和欠发达地区样本的空间自回归系数均大于全样本估计得到的空间自回归系数,故发达和欠发达地区内部的空间互动效应强于发达和欠发达地区之间的空间互动效应,呈现出“群分效应”。     

青藏高原及周边区域沙尘气溶胶三维分布和传输特征

利用MERRA-2再分析资料和CALIPSO星载激光雷达产品,分析了1980—2017年青藏高原和塔克拉玛干沙漠上空沙尘气溶胶的分布和传输特征.对比了MERRA-2与AERONET及MISR的气溶胶光学厚度（AOD）产品,其相关系数分别为0.809和0.776.基于MERRA-2资料分析表明,研究区域沙尘光学厚度（DAOD）按春、夏、秋、冬季依次递减.塔克拉玛干沙漠和青藏高原地区DAOD均在5月达最高值.青藏高原北部DAOD比南部高0.06~0.10,两地区的DAOD值差异在5月最高.自2000年开始,塔克拉玛干沙漠和印度恒河平原DAOD高值区强度和影响范围显著增大,对青藏高原的沙尘输送增强,印度沙尘对青藏高原的影响显著增加.CALIPSO观测表明,青藏高原上空的沙尘主要来自塔克拉玛干沙漠,传输量春季最大,秋、冬季最小;部分来自印度恒河平原,传输主要发生在夏、秋季.塔克拉玛干沙尘通过柴达木盆地向青藏高原传输,最远可至30°N,传输高度在4~8 km.冬季青藏高原上空的沙尘主要来自柴达木盆地.塔克拉玛干沙漠和青藏高原的最大气溶胶消光系数廓线分别出现在春季和夏季.塔克拉玛干沙漠和青藏高原地区沙尘层厚度多年平均值分别为1.00和0.82 km.2007—2017年,塔克拉玛干沙尘层厚度呈下降趋势,年下降率为0.018 km.青藏高原沙尘层厚度春季最大,冬季次之,夏季最小;沙尘层厚度年变化趋势不显著.     

Circular business models: Babbling initial exploratory

This research aims to map Brazilian companies that have business models aligned with the concept of the circular economy. Data were collected for this study through use of a survey and additional research based on the survey results. Within these businesses’ models, an emphasis on the second use of materials as well as the marketing of the product as a service has been highlighted.     

区域大气环境容量及其区域配置研究

以重庆市涪陵区为例,在了解区域大气环境功能区划及区域大气环境质量现状的前提下,采用A-P值法,对涪陵区十三五期间大气环境容量进行研究,并对辖区内的污染负荷进行预测,在此基础上,对大气污染总量控制指标进行分配.研究结果表明,在涪陵区化工园区的二氧化硫排放量已达到或超过总量控制指标,需要制定削减计划,新兴工业园区污染物排放量虽远小于总量控制指标,但根据城市发展规划需进行结构优化与合理布局.     

利用LUR模型模拟杭州市PM2.5质量浓度空间分布

模拟城市大气污染物浓度空间分布对研究城市空气质量及人体健康至关重要.本研究利用土地利用回归模型(Land Use Regression,LUR),提取包括污染点源因子、交通因子、人口因子、土地利用因子和气象因子等60个预测因子,基于地理加权算法(GWR)建立春、夏、秋、冬四个季节的模型,实现对杭州地区近地表PM_(2.5)质量浓度空间分布的预测.结果表明:基于地理加权回归算法时,检验模型的R2值分别达到0.76(春季)、0.70(夏季)、0.73(秋季)、0.76(冬季),模型能够解释PM_(2.5)浓度值80%以上的变异.每个季度杭州地区PM_(2.5)浓度变化不尽相同,但总体以杭州中部最高,西南部偏低.研究说明基于LUR模型模拟大尺度地区PM_(2.5)质量浓度空间分布是可行的.     

基于区域梯度式学习情景的长江经济带环境治理研究

长江经济带作为国家重大战略,面临开发与保护的巨大挑战,构建科学、高效的生态环境保护机制为其保驾护航成为重中之重。作为一个流域式生态共同体,区域统筹协调下的生态环境保护和治理是根本关键。本研究导入区域协同治理理念,提出构建梯度式渐进学习环境协同治理框架,并采用数据进行长江经济带环境污染治理的多情景测度与评价实证检验了梯度间以及梯度内部的环境保护与污染治理协调机制的潜在影响。最终,从中央、区域和地方三个层面提出梯度式学习视野下长江经济带环境治理策略。     

Assessment of Future Drought Conditions in the Chesapeake Bay Watershed

Impacts of climate change on the severity and intensity of future droughts can be evaluated based on precipitation and temperature projections, multiple hydrological models, simulated hydrometeorological variables, and various drought indices. The objective of this study was to assess climate change impacts on future drought conditions and water resources in the Chesapeake Bay (CB) watershed. In this study, the Soil and Water Assessment Tool (SWAT) and the Variable Infiltration Capacity model were used to simulate a Modified Palmer Drought Severity Index (MPDSI), a Standardized Soil Moisture index (SSI), a Multivariate Standardized Drought Index (MSDI), along with Coupled Model Intercomparison Project Phase 5 (CMIP5) climate models for both historical and future periods (f1: 2020‐2049, f2: 2050‐2079). The results of the SSI suggested that there was a general increase in agricultural droughts in the entire CB watershed because of increases in surface and groundwater flow and evapotranspiration. However, MPDSI and MSDI showed an overall decrease in projected drought occurrences due to the increases in precipitation in the future. The results of this study suggest that it is crucial to use multiple modeling approaches with specific drought indices that combine the effects of both precipitation and temperature changes.     

Consequences of ignoring dispersal variation in network models for landscape connectivity

Habitat loss and fragmentation can negatively influence population persistence and biodiversity, but the effects can be mitigated if species successfully disperse between isolated habitat patches. Network models are the primary tool for quantifying landscape connectivity, yet in practice, an overly simplistic view of species dispersal is applied. These models often ignore individual variation in dispersal ability under the assumption that all individuals move the same fixed distance with equal probability. We developed a modeling approach to address this problem. We incorporated dispersal kernels into network models to determine how individual variation in dispersal alters understanding of landscape-level connectivity and implemented our approach on a fragmented grassland landscape in Minnesota. Ignoring dispersal variation consistently overestimated a population's robustness to local extinctions and underestimated its robustness to local habitat loss. Furthermore, a simplified view of dispersal underestimated the amount of habitat substructure for small populations but overestimated habitat substructure for large populations. Our results demonstrate that considering biologically realistic dispersal alters understanding of landscape connectivity in ecological theory and conservation practice.     

Strategic Rat Control for Restoring Populations of Native Species in Forest Fragments

Forest fragments have biodiversity value that may be enhanced through management such as control of non‐native predators. However, such efforts may be ineffective, and research is needed to ensure that predator control is done strategically. We used Bayesian hierarchical modeling to estimate fragment‐specific effects of experimental rat control on a native species targeted for recovery in a New Zealand pastoral landscape. The experiment was a modified BACI (before‐after‐control‐impact) design conducted over 6 years in 19 forest fragments with low‐density subpopulations of North Island Robins (Petroica longipes). The aim was to identify individual fragments that not only showed clear benefits of rat control, but also would have a high probability of subpopulation growth even if they were the only fragment managed. We collected data on fecundity, adult and juvenile survival, and juvenile emigration, and modeled the data in an integrated framework to estimate the expected annual growth rate (λ) of each subpopulation with and without rat control. Without emigration, subpopulation growth was estimated as marginal (λ = 0.95–1.05) or negative (λ = 0.74–0.90) without rat control, but it was estimated as positive in all fragments (λ = 1.4–2.1) if rats were controlled. This reflected a 150% average increase in fecundity and 45% average increase in adult female survival. The probability of a juvenile remaining in its natal fragment was 0.37 on average, but varied with fragment connectivity. With juvenile emigration added, 6 fragments were estimated to have a high (>0.8) probability of being self‐sustaining (λ > 1) with rat control. The key factors affecting subpopulation growth rates under rat control were low connectivity and stock fencing because these factors were associated with lower juvenile emigration and higher fecundity, respectively. However, there was also substantial random variation in adult survival among fragments, illustrating the importance of hierarchical modeling for fragmentation studies. Control Estratégico de Ratas para Restaurar Poblaciones de Especies Nativas en Fragmentos de Bosque