日本以南黑潮流量对西北太平洋柔鱼渔场重心影响的滞后性分析

为研究西北太平洋海域黑潮流量对柔鱼Ommastrephes bartramii渔场的影响,本研究中结合1994—2010年西北太平洋海域黑潮流量和柔鱼渔场重心数据,采用阿尔蒙法建立了多项式分布滞后模型,通过分析黑潮流量异常与渔场重心偏移的互相关系数和模型的AIC值,确定了模型的最佳滞后期数,并添加了一阶滞后残差项以消除残差序列的自相关。结果表明:在经度方向上,黑潮流量异常在一年内对柔鱼渔场重心偏移没有明显的影响;而在纬度方向上,模型中黑潮流量异常变量的第12~15期系数均显著,分别为0.003 72(P<0.05)、0.004 93(P<0.01)、0.006 29(P<0.01)和0.007 81(P<0.05),说明黑潮流量异常会在6个月后的两个月内对渔场纬度重心产生正向的影响,模型调整后的相关系数为0.549。本研究中考虑了渔场对黑潮流量响应的时滞性,研究结果对延长西北太平洋柔鱼渔场预报的有效期限具有一定的参考意义。     

Spatial and temporal analysis of urban flood risk assessment

Urban flood risk assessment requires quantification of uncertainty that is spatially and temporally variable. This paper presents a new approach to urban flood risk assessment by: (a) integrating objective and subjective uncertainties and (b) providing full insight into spatial and temporal change of flood risk. A 1-D storm sewer model and a 2-D surface flow model are integrated to describe the dynamic interactions between overland flow on the streets and flow through the storm sewer network. The fuzzy set theory approach is used to assess spatial and temporal variability of urban flood damage, and the acceptable level of partial flood damage. The spatial and temporal variability of fuzzy performance indices: (i) combined reliability-vulnerability; (ii) robustness and (iii) resiliency, are generated as the outcome of the urban flood risk analysis. The methodology is illustrated using the residential community of Cedar Hollow (London, Ontario, Canada) as a case study.     

含水组地下水位变化对地面沉降影响的多元回归分析与预测

城市地面沉降是对城市规划建设、经济发展和人民生活构成威胁的地质灾害。为了探究地下水位与地面沉降的关系,本文对沧州市沧县各个地下含水组的地下水位变化、最大沉降量进行数据统计分析,建立了该地区基于含水组地下水位的多元回归模型。由模型计算结果可知,该模型适用于预测该城市区域的地面沉降趋势,并且分析各个地下含水组对地面沉降影响的相关程度。结果表明,第Ⅲ含水组地层是沧州市沧县形成地面沉降的最主要因素,为控制该区地面沉降提供了依据。     

Modified scaled distance regression analysis approach for prediction of blast-induced ground vibration in multi-hole blasting

The blast-induced ground vibration prediction using scaled distance regression analysis is one of the most popular methods employed by engineers for many decades. It uses the maximum charge per delay and distance of monitoring as the major factors for predicting the peak particle velocity (PPV). It is established that the PPV is caused by the maximum charge per delay which varies with the distance of monitoring and site geology. While conducting a production blasting, the waves induced by blasting of different holes interfere destructively with each other, which may result in higher PPV than the predicted value with scaled distance regression analysis. This phenomenon of interference/superimposition of waves is not considered while using scaled distance regression analysis. In this paper, an attempt has been made to compare the predicted values of blast-induced ground vibration using multi-hole trial blasting with single-hole blasting in an opencast coal mine under the same geological condition. Further, the modified prediction equation for the multi-hole trial blasting was obtained using single-hole regression analysis. The error between predicted and actual values of multi-hole blast-induced ground vibration was found to be reduced by 8.5%.     

Probabilistic seismic hazard analysis of North and Central Himalayas using regional ground motion prediction equations

Bulletin of Engineering Geology and the Environment - Recently developed region-specific GMPEs are used for a comprehensive seismic hazard analysis (SHA) of the North and Central Himalayas (NCH)...     

Spatial and temporal evolution of trihalomethanes in three water distribution systems

Spatial and seasonal changes in trihalomethane (THM) concentrations were investigated in three distribution systems of Quebec (Canada) which are supplied by different surface waters and which use a variety of physicochemical treatment strategies. The investigation was based on an intensive 25-week sampling programme, undertaken at a time of year when the temperature of southern Quebec surface waters exceeds 4 degrees C (April-November). THMs and other water quality and operational parameters were monitored at points along the distribution system--between the treatment plant and the system extremities--which represented variable residence times of water. Results showed that THM concentrations vary significantly (from 1.5 to 2 times, depending on the utility) between finished waters as they leave the plant and water at the system extremities. When water temperature exceeds 15 degrees C, spatial THM variations are particularly high (from 2 to 4 times, depending on the utility). The development of multivariate regression models showed that water temperature was a better predictor of THM seasonal variability than chlorine dose, surrogates of natural organic matter and pH. Also, initial THM formation (in finished waters leaving the plant) was a good predictor of THM levels at distribution system extremities.     

Spatial and temporal variation of particle number concentration in Augsburg, Germany

Epidemiological studies on health effects of outdoor air pollution are largely based on a single monitoring site to estimate the exposure of people living in urban areas. For such an approach two aspects are important: the temporal correlation and the spatial variation of the absolute levels of concentrations measured at different sites in an urban area. Whereas many studies have shown small spatial variability of fine particles in urban areas, little is known on how well a single monitoring station could represent the temporal and spatial variation of ultrafine particles across urban areas. In our study we investigated the temporal and spatial variation of particle number concentration (PNC) at four background sites in Augsburg, Germany. Two of them were influenced by traffic, one was placed in the outskirts of the city. The average PNC levels at two urban background sites with traffic impact were 16,943 cm(-3) and 20,702 cm(-3), respectively, compared to 11,656 cm(-3) at the urban background site without traffic impact (ratio 1.5 to 1.8). The Spearman correlation coefficients between the monitoring sites were high (r>0.80). The pronounced differences in absolute PNC levels suggest that the use of a single monitoring station in long-term epidemiological studies must be insufficient to attribute accurate exposure levels of PNC to all study subjects. On the other hand, the high temporal correlations of PNC across the city area of Augsburg implicate that in epidemiological time-series studies the use of one single ambient monitoring site is an adequate approach for characterizing exposure to ultrafine particles.     

Spatial and temporal distribution of pesticide residues in surface waters in northeastern Greece

A monitoring study of 147 compounds in surface river waters from northeastern Greece near Greek/Bulgarian/Turkish borders was carried out during 1999-2007. Based on agricultural use eight sampling points along the rivers Ardas, Evros and Erythropotamos were set up, covering the distance from the Greek/Bulgarian borders down to the river's discharge (river's delta) in the Greek territory. In total, 88 sampling events were carried out from 1999 to 2007. Pesticides were extracted by solid-phase extraction (SPE) and analyzed by gas chromatography-mass spectrometry (GC-EI-MS) using a multiresidue in-house analytical method including pesticides belonging to different chemical classes. Aquatic risk concerning the detected pesticides was assessed on the basis of the risk quotient (RQ = PEC/PNEC). From the 28 compounds (pesticides, metabolites and caffeine) that were detected in surface waters of northeastern Greece the soil applied pesticides were the most frequently detected. High pesticide concentrations were detected within 2 months of their application. Extreme pesticide concentrations were detected in the beginning of the irrigation season or just after high rainfall events. Generally, low levels of pesticide residues were found in the first sampling point (Greek/Bulgarian borders) of all rivers, however o′,p′ DDT, o′,p′ DDE and γ-HCH were mainly detected in this sampling point regarded as cross-boundary contamination. The most commonly encountered compounds in the river waters were atrazine, DEA, alachlor, trifluralin, prometryne, molinate, carbofuran, carbaryl and diazinon. Increased loading (primary as well as secondary peaks) seemed to be a consequence of application (timing, rate, frequency) and intense rainfall during the application period. Aquatic risk assessment revealed that from the 28 compounds that were constantly detected 12 showed non-acceptable risk when median concentrations were used as PEC and 18 when extreme concentrations were used as PEC values.     

生态智慧下鄂东南传统村落选址、布局与空间组合

在中国传统村落的规划与营建过程中,时刻注意自然与人文相协调的生态属性,对当代美丽乡村建设具有极大的参考价值.以鄂东南水南湾村为例,从村落生态的安全与和谐两个方面,对水南湾村的选址布局、空间组合等各个方面进行分析研究,寻找古人的生存哲学与生态智慧,也为传统村落的保护发展提供参考.     

Spatial climate variation pattern and regional prediction of rainfall in Jordan

Currently Jordan is facing various water problems accompanied by rapid population growth, urbanisation and industrialisation. It is of outmost importance to search for water resources augmentation possibilities leading to decision‐making procedures by addressing the rainfall sources as the main water resources in Jordan, through refined techniques. Point cumulative semivariogram (PCSV) samples are analysed in order to identify the regional dependence of the rainfall phenomena. Amman station is taken as a pivot site because of its location in the centre of the Kingdom, where the samples of the PCSV are calculated for eight systematic directions. Standard regional dependence function (SRDF) is obtained from the sample PCSV and the weighted average procedure is applied with the help of SRDF to predict the rainfall amounts. The radius of rainfall influence is determined for Amman in each direction. The cross‐validation methods are used to predict the rainfall in Amman using different samples representing along each direction. The result of cross‐validation method is acceptable in all samples with relative error not exceeding 10%, except in the desert sides where larger errors indicate weak regional dependence.