城市餐厨垃圾产量的空间降尺度模拟

文章以厦门岛为例,采用多元回归模拟和空间分析技术相结合的方法,选取了与厦门岛城市餐厨垃圾产量相关的土地利用、GDP、人口等相关社会经济地理因子进行空间化模拟研究。结果表明:(1)所选地理因子均对餐厨垃圾密度空间分布有一定影响,其中商住混合用地、商业服务用地、城镇住宅用地和城中村用地等土地利用类型的面积比例是主要的影响因子。(2)受多种因素共同影响,筼筜湖周边及厦门岛西南等商业繁华的区域餐厨垃圾密度较高,呈现空间集聚效应。(3)模型验证结果较为理想,各街道内餐厨垃圾总量模拟值与统计值比较符合,实现了厦门岛餐厨垃圾总量的降尺度模拟,是研究城市餐厨垃圾分布规律和实现餐厨垃圾产量空间化的一种尝试,以便为城市餐厨垃圾科学管理和决策提供参考,为餐厨垃圾资源化回收利用提供基础空间数据。     

数据缺失条件下基于MLP神经网络的水华风险预警方法研究

针对水华风险预警过程中相关监测指标数据缺失的问题,借鉴多元统计和随机分析构建了一种缺失数据插补方法,用于弥补现场调查数据的不足.基于主成分分析,对水华相关影响指标进行降维,确定水体水华风险预警模型的输入层变量.同时,采用多层感知器(MLP)人工神经网络模型对水华表征指标叶绿素a的浓度进行预测,并引入风险概率的概念,提出了水华风险概率计算公式,完善了水华预警的风险表达.最后以三峡库区典型支流大宁河为案例的研究证明了上述方法的可操作性.研究结果显示,插补数据条件下和未插补数据条件下的大宁河水华风险预警模型决定系数分别为0.9711和0.7769,前者的模型准确性更高,叶绿素a浓度预测效果更好;预测时段内大宁河11 d为水华蓝色预警(无警)级别,水华发生的风险概率为1.99%~18.61%;1 d达到水华橙色预警(中警)级别,水华发生概率为90.48%.     

上海市城乡梯度上土壤重金属空间分布及其影响因素定量分析

提出了两种上海市城乡梯度上土壤重金属空间格局及影响因素的研究方法:缓冲区分析方法和滑动窗口分析方法.缓冲区分析的结果表明,人口变化指数及2~3 km范围内的建设用地比例能显著影响Cd和Cu的空间分布(p0.05),而3 km范围内的道路密度显著影响Pb的浓度.滑动窗口分析的结果表明,Cd和Cu主要受工业活动的影响,而Pb受交通流量,以及反映城市景观扩张过程的景观形状指数的影响.相关分析表明,两种方式揭示了较为相似的土壤重金属空间累积影响因素,即工业活动相关的城市化过程.研究对理解城市化的发生机制及其重金属环境风险的管理有重要意义.     

Improved Weather Generator Algorithm for Multisite Simulation of Precipitation and Temperature

The KnnCAD Version 4 weather generator algorithm for nonparametric, multisite simulations of temperature and precipitation data is presented. The K‐nearest neighbor weather generator essentially reshuffles the historical data, with replacement. In KnnCAD Version 4, a block resampling scheme is introduced to preserve the temporal correlation structure in temperature data. Perturbation of the reshuffled variable data is also added to enhance the generation of extreme values. The Upper Thames River Basin in Ontario, Canada is used as a case study and the model is shown to simulate effectively the historical characteristics at the site. The KnnCAD Version 4 approach is shown to improve on the previous versions of the model and offers a major advantage over many parametric and semiparametric weather generators in that multisite use can be easily achieved without making statistical assumptions dealing with the spatial correlations and probability distributions of each variable.     

Range-Wide Selection of Catchments for Pacific Salmon Conservation

Abstract:  Freshwater ecosystems are declining in quality globally, but a lack of data inhibits identification of areas valuable for conservation across national borders. We developed a biological measure of conservation value for six species of Pacific salmon ( Oncorhynchus spp.) in catchments of the northern Pacific across Canada, China, Japan, Russia, and the United States. We based the measure on abundance and life-history richness and a model-based method that filled data gaps. Catchments with high conservation value ranged from California to northern Russia and included catchments in regions that are strongly affected by human development (e.g., Puget Sound). Catchments with high conservation value were less affected by agriculture and dams than other catchments, although only 1% were within biodiversity reserves. Our set of high-value areas was largely insensitive to simulated error, although classification remained uncertain for 3% of catchments. Although salmon face many threats, we propose they will be most likely to exhibit resilience into the future if a complementary mosaic of conservation strategies can be proactively adopted in catchments with healthy salmon populations. Our analysis provides an initial map of where these catchments are likely to be located.     

基于离散裂隙网络的烟台水封洞库渗水点分析

建立在致密结晶岩地区的地下水封洞库开挖过程中洞室及水幕巷道的渗水具有不均匀性,而现阶段主要在开挖后根据实际渗水量组织施工排水,若排水不及时容易造成洞室或巷道大面积浸水而形成安全风险。为在洞室开挖前对渗水点分布及渗水量进行一定预测,从而提前且合理安排排水工作,降低施工风险,以烟台地下水封洞库丁烷库区为例,在对该库区裂隙调查结果进行一定的统计分区后,采用Monte-Carlo随机模拟方法建立离散裂隙网络模型,通过多次迭代确定裂隙模拟置信区间,并选取在置信区间范围内的裂隙模拟结果按照立方定律求取渗透系数,按区间进行水封洞库渗水点分布区划分,同时与实测大流量渗水区域进行比对,结果发现两者具有较好的一致性,表明该方法能借助前期裂隙统计结果预测洞室开挖后渗水情况,协助组织施工期洞室排水。     

Fuzzy modelling to identify key drivers of ecological water quality to support decision and policy making

Water quality modelling is an effective tool to investigate, describe and predict the ecological state of an aquatic ecosystem. Various environmental variables may simultaneously affect water quality. Appropriate selection of a limited number of key-variables facilitates cost-effective management of water resources. This paper aims to determine (and analyse the effect of) the major environmental variables predicting ecological water quality through the application of fuzzy models. In this study, a fuzzy logic methodology, previously applied to predict species distributions, was extended to model environmental effects on a whole community. In a second step, the developed models were applied in a more general water management context to support decision and policy making. A hill-climbing optimisation algorithm was applied to relate ecological water quality and environmental variables to the community indicator. The optimal model was selected based on the predictive performance (Cohen’s Kappa), ecological relevance and model’s interpretability. Moreover, a sensitivity analysis was performed as an extra element to analyse and evaluate the optimal model. The optimal model included the variables land use, chlorophyll and flow velocity. The variable selection method and sensitivity analysis indicated that land use influences ecological water quality the most and that it affects the effect of other variables on water quality to a high extent. The model outcome can support spatial planning related to land use in river basins and policy making related to flows and water quality standards. Fuzzy models are transparent to a wide range of users and therefore may stimulate communication between modellers, river managers, policy makers and stakeholders.     

Influence of avian reproduction ecotoxicological endpoints in the assessment of plant protection products

The aim of this paper is to examine the statistical relevance of bird species on the endpoints of avian long–term toxicity studies (eggs laid, eggs set, eggs hatching, embryo survivor, 14-day old survivors and eggshell thickness). Data from 561 animals of three different species (Colinus virginianus, Anas platyrynchos and Coturnix coturnix japonica) tested with five different pesticides were analyzed in this study. The substances considered were: Thiamethoxam (EZ-3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro)amine), Thiacloprid ((Z)-3-(6-chloro-3-pyridylmethyl)-1,3-thiazolidin-2-ylidenecyanamide), Acetamiprid ((E)?N ¹-[(6-chloro-3-pyridyl)methyl]-N ²-cyano-N ¹-methylacetamidine), Phosmet (O,O-dimethyl S-phthalimidomethyl phosphorodithioate) and Dicofol (2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol). Several general lineal mixed models were conducted to evaluate the factors affecting variables used in long-term reproductive toxicity tests. Test significance was p < 0.01 in all models tested. Model R² value was high (0.80) for all variables except for eggs laid (R² = 0.42) for the three species studied. Tukey studentized range test showed significant differences among species and pesticides. For pre-hatching period the differences were significant for eggs laid and eggs set among species. C. japonica showed statistical differences for egg hatching. With respect to embryo survivor and 14 days old survival, significant different were found for C.virginianus and A. platyrynchos, respectively. These results indicate that the selected species have an influence in the endpoints to be used for risk assessment.     

On the environmental consequences of intra-industry trade

In the trade and environment debate, the relevance of examining the impact of a location's intra-industry trade (IIT) on environmental quality cannot be overemphasized, in part, due to the increasing prominence of such trade and the paucity of related empirical evidence. Although existing studies largely indicate overall trade to be pro-environment, the consequences of IIT may differ owing to greater varieties of intermediate and final goods, easier technology diffusion via trade in similar goods, productivity gains from within-sector reallocations, and increased innovation. However, identification of the causal effect is plagued by the potential endogeneity of IIT attributable to crucial unobservables and measurement error. In this light, utilizing an instrumental variables strategy and data on multiple environmental indicators from roughly 200 countries over 2000-2005, we investigate IIT's impact on the environment. To measure IIT, we rely on two indexes of within-industry specialization based on changes in and levels of sector-level trade. Regardless of the indicator of IIT or environmental performance, across several sets of instruments, we mostly find (i) IIT to benefit the environment, (ii) overall trade to be less pro-environment than IIT, and (iii) concerns over endogeneity to be relevant.     

Effectiveness of Multi‐Site Weather Generator for Hydrological Modeling1

Khalili, Malika, François Brissette, and Robert Leconte, 2011. Effectiveness of Multi‐site Weather Generator for Hydrological Modeling. Journal of the American Water Resources Association (JAWRA) 1‐12. DOI: 10.1111/j.1752‐1688.2010.00514.x Abstract: A multi‐site weather generator has been developed using the concept of spatial autocorrelation. The multi‐site generation approach reproduces the spatial autocorrelations observed between a set of weather stations as well as the correlations between each pair of stations. Its performance has been assessed in two previous studies using both precipitation and temperature data. The main objective of this paper is to assess the efficiency of this multi‐site weather generator compared to a uni‐site generator with respect to hydrological modeling. A hydrological model, known as Hydrotel, was applied over the Chute du Diable watershed, located in the Canadian province of Quebec. The distributed nature of Hydrotel accounts for the spatial variations throughout the watershed, and thus allows a more in‐depth assessment of the effect of spatially dependent meteorological input on runoff generation. Simulated streamflows using both the multi‐site and uni‐site generated weather data were statistically compared to flows modeled using observed data. Overall, the hydrological modeling using the multi‐site weather generator significantly outperformed that using the uni‐site generator. This latter combined to Hydrotel resulted in a significant underestimation of extreme streamflows in all seasons.