Spatial Calibration and Temporal Validation of Flow for Regional Scale Hydrologic Modeling1

Abstract: Physically based regional scale hydrologic modeling is gaining importance for planning and management of water resources. Calibration and validation of such regional scale model is necessary before applying it for scenario assessment. However, in most regional scale hydrologic modeling, flow validation is performed at the river basin outlet without accounting for spatial variations in hydrological parameters within the subunits. In this study, we calibrated the model to capture the spatial variations in runoff at subwatershed level to assure local water balance, and validated the streamflow at key gaging stations along the river to assure temporal variability. Ohio and Arkansas‐White‐Red River Basins of the United States were modeled using Soil and Water Assessment Tool (SWAT) for the period from 1961 to 1990. R² values of average annual runoff at subwatersheds were 0.78 and 0.99 for the Ohio and Arkansas Basins. Observed and simulated annual and monthly streamflow from 1961 to 1990 is used for temporal validation at the gages. R² values estimated were greater than 0.6. In summary, spatially distributed calibration at subwatersheds and temporal validation at the stream gages accounted for the spatial and temporal hydrological patterns reasonably well in the two river basins. This study highlights the importance of spatially distributed calibration and validation in large river basins.     

Assessing coastal vulnerability to climate change: comparing segmentation at global and regional scales

Recent concerns about potential climate-change effects on coastal systems require the application of vulnerability assessment tools in order to define suitable adaptation strategies and improve coastal zone management effectiveness. In fact, while various research efforts were devoted to evaluate coastal vulnerability to climate change on a national to global level, fewer applications were carried out so far to develop more comprehensive and site-specific vulnerability assessments suitable to plan possible adaptation measures at the regional scale. In this respect, specific indicators are needed to address climate-change-related issues for coastal zones and to identify vulnerable areas at the regional level. Two sets of coastal vulnerability indicators were selected, one for regional and one for global studies, respectively, concerning the same features of coastal systems, including topography and slope, geomorphological characteristics, presence and distribution of wetlands and vegetation cover, density of coastal population and number of coastal inhabitants. The proposed set of indicators for the regional scale was chosen taking into account the availability of environmental and territorial data for the whole coastal area of the Veneto region and was based on site-specific datasets characterized by a spatial resolution appropriate for a regional analysis. Moreover, a GIS-based segmentation procedure was applied to divide the coastline into linear segments, homogeneous in terms of vulnerability to climate change and sea-level rise at the regional scale. This approach allowed to divide the Veneto shoreline into 140 segments with an average length of about 1 km, while the global scale approach identified four coastal segments with an average length of about 66 km. The performed comparison indicated how the more detailed approach adopted at the regional scale is essential to understand and manage the complexities of the specific study area. In fact, the 25-m DEM employed at the regional scale provided a more accurate differentiation of the coastal area's elevation and thus of coastal susceptibility to the inundation risks, compared to the 1-km DEM used at the global level. Moreover, at the regional level the use of a 1:20,000 geomorphological map allowed to differentiate the unique landform class detected at the global level (e.g., fluvial plain) in a variety of more detailed coastal typologies (e.g., open coast eroding sandy shores backed by bedrock) characterized by a different sensitivity to climate change and sea-level rise. Accordingly, the information provided by regional indicators can support decision-makers in improving the management of coastal resources by considering the potential impacts of climate change and in the definition of appropriate actions to reduce inundation risks, to avoid the potential loss of valuable wetlands and vegetation and to plan the nourishment of sandy beaches subject to erosion processes.     

自然资源禀赋与城市化水平关系的多尺度考察

通过对单体区域在时间序列上的分析和对多个区域面板数据集综合水平的横向比较，本文在多个尺度上验证了自然资源禀赋在区域城市化过程的“资源诅咒”假说，并且通过在省际层面上建立经济计量模型进行理论检验，也得出“资源诅咒”效应在一定程度上的确存在的结论。文章还分析了城市化过程中自然资源产生限制作用的作用机理。认为这种效应是多种要素综合作用的结果，并提出了相应的政策建议。这项研究在理论上丰富了城市化动力机制和“资源诅咒”假说的研究，在实践上也具有一定的现实意义。     

陕西省环保投资绩效DEA实证分析

为优化环保投资结构,有效使用环保投资,借助于数据包络分析方法 (DEA)对陕西省2002～2009年的环保投资绩效进行实证分析。实证分析结果表明,这些年陕西省环保投资技术效率的均值为0.985,其在规模效率上处于规模合理或规模递增阶段占75%,在技术效率上处于最佳和有效状态的占75%。说明陕西省环保投资绩效保持在一个较好的水平,但陕西省环保投资还没有充分发挥作用,环保投资对经济发展和社会进步的贡献偏低,人才队伍建设力度水平亟待提高。陕西省政府可采取一些措施使陕西环保绩效进一步提高。     

臭氧对中温循环冷却水系统的缓蚀性能研究

循环冷却水系统中普遍存在结垢腐蚀现象,目前常用的解决方法是在系统中加入缓蚀阻垢药剂,臭氧(O3)对循环水冷却系统同时具备阻垢、缓蚀、杀菌等多重功能。采用臭氧处理中温循环冷却水,研究在不同臭氧投加量时系统的腐蚀情况,确定最佳投加量。结果表明:当臭氧投加量为4.5 mg/L时,20碳钢和铸铁的缓蚀能力最佳。20碳钢腐蚀率最低为0.228 mm/a,比空白对照组降低了75%;铸铁的最低腐蚀率为0.282 mm/a,比空白对照组降低了61.5%。当臭氧投加量为9.0 mg/L时,镀锌试片的腐蚀率在0.206~0.275 mm/a,比空白对照组降低了38.2%左右,缓蚀效果较为明显。     

Cognitive and affective identification: Exploring the links between different forms of social identification and personality with work attitudes and behavior

Individuals often identify with groups in order to either reduce perceived uncertainty or to feel better about who they are as individuals. This suggests that cognitive and affective identification are two distinctive forms of social identification in organizational settings. Because neurotic individuals are highly motivated to reduce perceived uncertainty, they will tend to identify cognitively with groups. Extraverted individuals, on the other hand, are highly motivated to enhance how they feel about themselves and thus identify affectively with groups. Across three studies, we develop measures of cognitive and affective identification and then show that neuroticism is positively related to cognitive identification, whereas extraversion is positively related to affective identification. We also find that affective identification provides incremental predictive validity over and above cognitive identification in the prediction of organizational commitment, organizational involvement, and organizational citizenship behaviors. Copyright © 2012 John Wiley & Sons, Ltd.     

淮河水质变清的产业规模制约与规划漏洞补丁

为分析产业规模对淮河水质变清的制约作用,论证实现淮河水质变清目标的必要条件,考察规划方案的不充分性缺陷,首先计算了少数几个行业的部分产品在完全达标排放情形下的COD排污总量。根据1995年淮河流域四省少数几个行业的部分产品实际产量和当时执行的水污染物排放标准,计算得到的COD达标排污总量值(36.95万t)就已超过水质变清目标下的最大允许排放总量值(36.8万t),其中流域内造纸行业的COD达标排放总量就高达27.66万t,占实现淮河流域水质变清目标时所允许最大排放量36.8万t的75.2%。《淮河流域水污染防治规划及"九五"计划》未涉及行业或产品的规模控制、最大允许COD排污总量的行业或产品分配、目标可达性与方案充分性的论证等内容。规划方案与规划目标是相互脱节的,无法保障规划目标的实现。产业结构中排污负荷高的产品生产规模过大且没有得到严格有效的压缩控制是导致淮河流域水质变清目标未能实现的重要原因之一。要想实现淮河水质变清,严格控制全流域内排污负荷高的工业产品总产量规模是必要条件之一。     

SARS流行期的气候学尺度分析

对SARS疫区流行期的气候特征作了统计分析.发现它们共同的特征是月均温在5～22 ℃,降水偏少,约在90 mm以下,其中疫情爆发月均温13～17 ℃.在疫区,如果出现气温日较差较小、大气污染指数高的天气,大约8 d后出现疫情峰值.由于SARS第一次在人群中发现,并且缺乏病毒学研究,本项研究的结论是解释性的.     

北京地区湿式脱硫除尘系统管路结垢现象分析

分析了北京地区供热企业湿式脱硫除尘系统普遍存在的循环水管路结垢问题,指出体系中Ca^2 和SO^2-4的积累是造成结垢的根本原因,采用合适的烟气脱硫方法和工艺是解决脱硫设备结垢问题的根本所在;添加少量合适絮凝剂是减少循环水系统管路结垢的重要措施。     

基于概率模型的农地转用外部性测算——以天津市静海区为例

准确地量化农地转用外部性能够为促进外部性内化、建设用地聚集的政策提供参考。论文对农地转用外部性界定和识别进行了理论分析,利用农地转用概率模型估算天津市静海区2006—2014年农地转用的外部性,分析地块特征对农地转用概率的影响,讨论了外部性与建设用地聚集的关系。针对静海区2006—2014年数据的分析结果表明,每有1 hm²农地转用为商住用地,周边0~200、200~400、800~1 600 m范围农地受外部性影响分别为0.91×10⁴、0.91×10⁴、0.33×10⁴ 元/hm²,每有1 hm²农地转用为住宅用地,周边800~1 600 m范围内农地受外部性影响为0.18×10⁴ 元/hm²。农地转用正外部性偏小,聚集效应不足,可能是建设用地分散的重要原因,论文还对外部性测算方法以及地块特征的农地转用影响进行了讨论。