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21.
The incorporation of land use (LU) data with socioeconomic data is a main issue in modelling. This is as a result of difference in data model and scale. This study proposed and tested the change–pattern approach, which allows the incorporation of these data sets in modelling LU change. Focusing on LU dynamics for a selected part of the Thames Gateway within the City of London, the approach tested two different methods of input selection for the modelling operations. Variables selected from these two methods serve as inputs into several neural networks tested in order to identify the direction of change for each of the LU types within the study area. The result shows that direction of LU change across the study area could be identified when spatial morphology of the area and socioeconomic variables are considered. Some classes of change could be identified fairly accurately using landscape metrics indicating level of fragmentation, extent of LU patches, shape complexity of LU patches in combination with some socioeconomic variables.  相似文献   
22.
We present how state-and-transition models (STMs) may be derived from image data, providing a graphical means of understanding how ecological dynamics are driven by complex interactions among ecosystem events. A temporal sequence of imagery of fine scale vegetation patterning was acquired from close range photogrammetry (CRP) of 1 m quadrats, in a long term monitoring project of Themeda triandra (Forsskal) grasslands in north western Australia. A principal components scaling of image metrics calculated on the imagery defined the state space of the STM, and thereby characterised the different patterns found in the imagery. Using the state space, we were able to relate key events (i.e. fire and rainfall) to both the image data and aboveground biomass, and identified distinct ecological ‘phases’ and ‘transitions’ of the system. The methodology objectively constructs a STM from imagery and, in principle, may be applied to any temporal sequence of imagery captured in any event-driven system. Our approach, by integrating image data, addresses the labour constraint limiting the extensive use of STMs in managing vegetation change in arid and semiarid rangelands.  相似文献   
23.
盐池北部风沙区土地利用变化的社会经济效应   总被引:1,自引:0,他引:1  
方广玲  吴斌  张宇清  吴秀芹 《生态环境》2010,19(5):1132-1137
以盐池北部风沙区为研究区域,利用1996—2007年土地利用变更调查与社会经济统计数据,借助典型相关分析,提取沙区农村土地利用变化对社会经济发展影响的主要方面。结果表明:(1)研究区土地利用变化对农村经济总体水平、经济结构、社会发展具有显著影响;(2)种植业、林业、牧业产值与粮食总产量是衡量研究区农村经济总体水平的重要指标,耕地、林地、居民点、沙地组成对其影响显著;(3)人口产业结构与居民收入结构反映了研究区农村社会发展、劳动力就业情况,受林地和沙地组成影响较大;(4)林地和沙地组成对地区农业结构,尤其是林业产值比重影响较大。沙区土地利用变化的社会经济效应分析,为土地利用结构调整方向提供依据,目的是促进沙区种植业结构调整、林牧业发展、农村劳动力合理分配。  相似文献   
24.
A major chemical company established a formal incident investigation and reporting system several years ago. The original system focused heavily on worker-related injuries, illnesses, and near-misses and was used primarily to track statistics reportable to the Occupational Safety and Health Administration (OSHA). This Occupational Injury and Illness (OII) approach has been recognized to be an ineffective tool for measuring, predicting, and preventing process safety incidents. The Center for Chemical Process Safety (CCPS) recently published guidelines on how to establish safety metrics for the measurement and reduction of process safety incidents. The process safety metrics approach relies upon leading and lagging metrics to improve organization process safety. This paper is a case study of the analysis of one organization’s incident database, which represents approximately five years of data from over a dozen facilities. The aim of this investigation was to extract useful process safety metrics from the incident investigation and reporting system, which would be pertinent to the types of process units and process functions at these facilities. This paper will discuss the approach taken to extract process incident information from an OII-based database and present the difficulties of performing an analysis on such a database. This paper provides guidance on how to migrate an existing OII-based reporting system to a program that includes process safety metrics in accordance with industry best practices.  相似文献   
25.
物质代谢研究进展综述   总被引:5,自引:0,他引:5  
传统的线性经济生活模式导致人类社会面临着巨大的环境压力,因此为提高资源的利用效率,实现社会经济的可持续发展,物质代谢研究逐渐成为近年来国际研究领域的热点问题。文章从三方面对国际上关于物质代谢研究进展做了阐述:①物质代谢的研究背景;②物质代谢的基础性研究,包括不同层次的物质代谢吞吐量的研究和物质代谢定量分析方法的探讨;③物质代谢相关的研究进展,包括土地利用/覆盖变化、自然环境效应和可持续发展与物质代谢作用关系的讨论。最后,对其未来的发展方向提出了一些建议,认为除了要进一步完善物质代谢研究方法和模型外,还应从土地利用/覆盖变化、研究尺度、政策和行为、生态环境效应等角度对物质代谢进行拓展分析。  相似文献   
26.
张微微  李晓娜  王超  赵春桥  史瑞双 《环境科学》2020,41(11):4895-4904
基于密云水库上游北京境内白河段9个监测断面的水质数据,利用多元统计分析方法分析不同空间尺度(100、200、300、500和1000 m)河岸带缓冲区土地利用景观格局特征与水质总氮(TN)和总磷(TP)的关联性,识别水质对景观特征响应的最佳缓冲区尺度.结果表明,密云水库上游北京境内白河周边土地利用景观格局对水质的影响随着河岸缓冲区不同宽度的变化而不同,在河岸小尺度缓冲区表现得更明显,对水质TN和TP空间分异解释的最佳尺度分别为300 m和100 m河岸缓冲区.300 m缓冲区尺度,耕地斑块密度和草地聚集指数是影响河流TN的主要指数.100 m缓冲区尺度,城乡居民点面积比例对河流TP影响显著.该研究表明,优化河岸缓冲区300 m宽度范围内的景观格局,特别是耕地和林草地的合理配置提高农业景观的连通性和聚集度以及岸边城乡居民点面积与污染物排放控制,对于改善北京境内白河段河流水质的生态功能和保障密云水库饮用水安全十分重要.  相似文献   
27.
The Environmental Monitoring and Assessment Program (EMAP) is proposing an ambitious agenda to assess the status of streams and estuaries in a 12-State area of the western United States by the end of 2003. Additionally, EMAP is proposing to access landscape conditions as they relate to stream and estuary conditions across the west. The goal of this landscape project is to develop a landscape model that can be used to identify the relative risks of streams and estuaries to potential declines due to watershed-scale, landscape conditions across the west. To do so, requires an understanding of quantitative relationships between landscape composition and pattern metrics and parameters of stream and estuary conditions. This paper describes a strategic approach for evaluating the degree to which landscape composition and pattern influence stream and estuary condition, and the development and implementation of a spatially-distributed, landscape analysis approach.  相似文献   
28.
Process hazard analysis (PHA) studies (e.g. HAZOP) identify hazard scenarios and each scenario is examined individually to decide whether risk reduction measures are needed. However, much more can be done to benefit from the contents of studies.PHA studies contain so much data that a manual review is precluded from yielding insights into their results. Fortunately, valuable information can be extracted using metrics and analytics that consider all the contents of a PHA study. The management of safety, operability, reliability, utilization, and loss prevention can all be improved.Metrics evaluate the contents of PHA studies to provide insights into the safety of processes and the quality of studies. Measures of process safety and study quality can be compared with norms to identify possible departures that may need to be addressed.Rather than focusing decision making on the risks of individual hazard scenarios, as is common practice, analytics enable a deeper analysis of the entire set of scenarios for a process. This enables better decisions to be made on where and how risk reduction resources should be allocated. Analytics can also be used to prioritize maintenance, training, and other activities.Various analytics and metrics for PHA studies are described together with examples that illustrate their use.  相似文献   
29.
ABSTRACT

Forest cover dynamics (1993-2018) was assessed in two regions on the Yucatan Peninsula: Zona Maya (ZM), 67% indigenous with shifting cultivation and community forestry; and Bacalar–Rio Hondo (BRH), mainly commercial agriculture and pastureland. Degradation (12,915 ha y?1) exceeded deforestation (5882 ha y?1) and was worse in BRH. In BRH there was a net forest loss (?1.6% y?1) associated with pastureland and commercial agriculture. In ZM, mature forest recovery (1.4% y?1) and dynamic forest cover (continuous loss and gain) were associated with shifting cultivation. Changes were more intense during 2011–2018 and gains of mature forest in ZM and deforested areas in BRH targeted secondary vegetation. Fragments of mature and secondary vegetation decreased, and connectivity improved in ZM, but opposite trends occurred in BRH. Reporting and monitoring deforestation using Global Forest Watch data is inadequate since 62% of forest cover loss represent degrading or recovering forest cover.  相似文献   
30.
农业排水沟渠硝态氮吸收动力学特征及相关性分析   总被引:1,自引:0,他引:1  
为揭示农业排水沟渠NO_3~--N吸收动态变化特征,选择溴化钠(Na Br)为保守示踪剂、硝酸钾(KNO3)为添加营养盐,于2016年10月至2017年4月在合肥地区某一源头溪流开展5次示踪试验,并以TASCC方法和Michaelis-Menten(M-M)方程模拟NO_3~--N吸收动力学特征,结果表明,背景浓度条件下排水沟渠完全混合子渠段U_(amb)和V_(f-amb)的变化范围分别为11.40~69.13μg·(m~2·s)~(-1)[均值为34.45μg·(m~2·s)-1]、0.07~0.43 mm·s~(-1)(均值为0.24 mm·s~(-1)),相应地Sw-amb变化范围为92.51~405.74 m(均值为199.06 m),明显小于排水沟渠长度(也就是2.5 km),表明沟渠具有较强的NO_3~--N滞留潜力.M-M方程较好地拟合了NO_3~--N吸收动力学特征,参数Umax变化范围为158~1 280μg·(m~2·s)~(-1)[均值为631.13μg·(m~2·s)~(-1)],Km变化范围为0.16~5.52 mg·L~(-1)(均值为1.46 mg·L~(-1)).相关分析表明,Sw-amb与NO_3~--Namb呈显著负相关、Uamb与NO_3~--Namb呈极显著正相关,其它螺旋指标与NO_3~--N背景浓度的相关性均不明显;水文因素对NO_3~--N滞留影响也不显著,而沟渠槽道地貌特征指标Фw、ФA与大部分螺旋指标都呈显著相关性,表明槽道地貌特征对NO_3~--N滞留影响相对较为重要.  相似文献   
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