基于信息熵的武汉城市土地利用空间结构变动分析

借助城市土地利用空间结构的信息熵和均衡度概念,揭示了武汉城市在20世纪90年代土地利用结构的空间变化规律,得出土地利用职能类型收缩、城市用地趋向不均衡发展态势的结论.利用主成分与灰色关联相结合的方法找出影响武汉城市土地利用空间结构变动的主要动力因子,它们分别是城市福利和城市社会结构变化推动因子、城市产业结构变化拉动因子和城市建设与改造压力因子,其中后两个因子是驱动城市土地利用空间发生变化的最显著性因子.     

城市化进程中土地利用结构的时序变化及驱动力——以辽宁省为例

根据1995—2008年《辽宁省统计年鉴》及土地利用数据,以人口城市化率反映城市化水平,基于信息熵和均衡度原理,分析了辽宁省城市化过程中土地利用结构的动态变化特征,探讨了土地利用结构信息熵和均衡度动态变化的驱动机制。结果表明,伴随着城市化的不断加快,1995—2008年辽宁省土地利用信息熵、均衡度呈现波动状态,各土地利用类型的面积占土地总面积的比例逐渐趋于均衡。但从总体趋势看,土地利用结构的均质性较差,人口因素、经济因素是影响土地利用结构信息熵和均衡度时空变化的主要驱动因子。     

县级土地利用动态变化及驱动力分析——以郑州市中牟县为例

以郑州市中牟县为例,利用土地详查和统计数据等资料,建立土地利用动态变化模型,分析了中牟县1996-2008年土地利用数量、速度、程度、区域差异等变化,揭示中牟县土地利用变化特征.同时,采用主成分分析法得出城镇化进程和收入水平提高是影响中牟县土地利用变化的主要驱动因素.     

新疆种植业土地利用变化及驱动力研究

种植业土地利用方式是关系农民增收的重要因素.采用主成分分析法,运用定量分析与定性描述的方法,全面分析了新疆 1978～2002年期间种植业土地利用变化的驱动因素.研究表明:影响新疆种植业土地利用规模的主要因素按影响力大小排列为科技进步、农业发展、农产品价格,而影响种植业结构变化的主要因素则有市场因素、粮食生产能力、产业政策.在此基础上,建立多元回归预测模型,为种植业土地合理利用提供评价依据,促进农民增收.     

张掖市地表景观格局演变与空间优化研究

土地利用方式和时空格局变化是人类活动的重要体现,掌握土地动态特征及发展趋势对实现可持续发展目标至关重要。以GlobeLand30地表覆盖数据为基础,利用Markov模型与PLUS模型对张掖市的土地利用结构与用地扩张的驱动因素进行了分析,探究了各类用地的转化规则。研究结果表明,耕地、林地、草地与人造地表是影响空间格局变化的主导用地类型,社会经济因素如交通条件等是影响土地扩张与区域协调发展的重要原因。     

基于CA-Markov模型的新疆克州土地利用动态模拟研究

利用"3S"技术及IDRISI软件中的CA-Markov模型,以2005年为起始时刻,对新疆克州2015年土地利用格局进行模拟预测.研究认为:研究区土地利用覆盖结构呈现"两大、四小"的特点,即:草地及未利用土地面积大,而耕地、林地、水域及城乡居民工矿建设用地面积较小;与2005年相比,模拟的2015年研究区土地利用结构变化不大,仍然是以草地和未利用地面积为主,各土地利用类型面积变化也不大,其中,耕地、林地和城乡建设用地面积将略有增加,而草地、水域面积将有所减少,未利用地面积也有一定的增加,总体上,研究区内生态环境将可能进一步呈恶化趋势.     

云南省罗平县土地利用变化及驱动力研究

土地利用问题是实现生态脆弱区环境-经济协调发展的关键所在。选取喀斯特地区的罗平县作为研究对象，将遥感、GIS和多元统计技术结合运用于土地利用变化研究中，对罗平县1990～2001年的土地利用变化情况及驱动力进行了研究。结果表明，罗平县耕地逐年减少；影响耕地变化的主要驱动因子包括人口、经济和社会投资。     

小尺度热点地区土地利用/覆被变化研究--以淮南市为例

利用指数模型方法,从区域土地利用/覆被变化(LUCC)的速度、土地流向、空间结构和土地利用程度等方面对淮南市1996～2003年间土地利用变更数据进行了定量描述和分析,揭示了淮南市土地利用及变化的特征,并针对在工矿和居民点整理复垦、土地利用程度等方面存在的问题提出了相应建议,为实现土地资源的合理利用提供科学依据.     

干旱区典型绿洲城市LUCC及社会人文驱动因素分析——以乌鲁木齐市为例

选取2001—2011年的相关数据,采用因子分析、相关性分析的方法对乌鲁木齐市土地利用/土地覆被变化及社会人文因素进行分析。结果表明:①研究区的土地利用类型的整体结构差异明显,农用地占据绝对优势,其比重均在79%以上,但面积和比例持续缩小;建设用地则处于相对劣势的地位,其比重仅为3.2%左右,但规模和比重却在不断扩大。②11年来,研究区土地利用变化的总强度不大,仅为36%,各用地类型的动态度为:建设用地农用地其他用地。③各类用地变化强度的顺序为:交通用地园地居民点工矿用地耕地水域水利设施用地牧草地其他农用地其他建设用地。④影响乌鲁木齐市土地利用类型变化的4个因子及其影响程度由高到低的排序为:区域经济产业结构交通发展社会人口。     

基于DEM的土地利用类型与地形因子关系研究——以重庆市永川朱龙花等6村为例

以重庆市永川区陈食街道朱龙花等6村为例,基于全国二次调查土地利用现状图和数字高程模型(DEM),在ArcGIS 9.3平台支持下,进行了30m×30m栅格单元的土地利用与地形因子关系研究,探讨了重庆市永川土地利用特征。结果表明,海拔高度、坡度和坡向与土地利用类型的综合分析有助于从定量剖析土地利用空间分布特征;朱龙花等6村海拔、坡度及坡向均值分别为345m、17.28°和271.25°(西坡);采用高程分带、坡度分级及坡向分类的方法能直观展示土地利用格局特征。耕地(水田及旱地)主要分布在低海拔的平原和丘陵上,阳坡面积大于阴坡,水田尤为突出。园地和林地主要分布在海拔低于400m的丘陵上,坡度小于15°,西坡和西北坡分布最多;草地主要分布在海拔200—500m的平原和丘陵上,坡度小于25°,各坡向均有少量分布;水域、水利建设用地、城镇村及工矿用地分布格局类似,主要分布在300—400m的丘陵上,坡度小于6°,东坡、东南坡分布较多;其他土地分布在海拔低于500m,坡度小于25°,西坡分布较多。从土地利用与生态环境的协调发展角度看,该区域土地利用空间分布格局基本符合生态环境建设的要求,约有2.34hm2的耕地位于坡度大于25°的缓陡坡和陡坡上,应继续推行退耕还林、还草。研究结果表明,地形因子对土地利用的空间格局的影响较大;同一地形因子不同级别下的土地主导利用方式各异,土地利用类型的优势区域不尽相同。     

Projected Changes in Discharge in an Agricultural Watershed in Iowa

Our improved capability to adapt to the future changes in discharge is linked to our capability to predict the magnitude or at least the direction of these changes. For the agricultural United States Midwest, too much or too little water has severe socioeconomic impacts. Here, we focus on the Raccoon River at Van Meter, Iowa, and use a statistical approach to examine projected changes in discharge. We build on statistical models using rainfall and harvested corn and soybean acreage to explain the observed discharge variability. We then use projections of these two predictors to examine the projected discharge response. Results are based on seven global climate models part of the Coupled Model Intercomparison Project Phase 5 and two representative concentration pathways (RCPs 4.5 and 8.5). There is not a strong signal of change in the discharge projections under the RCP 4.5. However, the results for the RCP 8.5 point to a stronger changing signal related to larger projected increases in rainfall, resulting in increased trends, in particular, in the upper part of the discharge distribution (i.e., 60th percentile and above). Examination of two hypothetical agricultural scenarios indicates that these increasing trends could be alleviated by decreasing the extent of the agricultural production. We also discuss how the methodology presented in this study represents a viable approach to move forward with the concept of return period for engineering design and management in a nonstationary world.     

Investment in human capital in Africa

Summary The author analyses the problems currently faced by the African continent, recognises six factors which he believes are important in influencing the analysis, and argues that the only secure, renewable asset any country or continent has, is its people. He maintains that people development, rather than the classical economic forms of encouraging development, offers Africa a viable way forward. He then identifies a number of specific issues within such a strategy of investment in human capital.Brian Walker is the President of the International Institute for Environment and Development (IIED), and this address was given at the inaugural meeting of the International Year of Shelter for the Homeless, in London, on 18th April, 1985. A second, earlier, associated address was published inThe Environmentalist 5(3) 167–170.     

Pesticides in rain in four agricultural watersheds in the United States

Rainfall samples were collected during the 2003 and 2004 growing seasons at four agricultural locales across the USA in Maryland, Indiana, Nebraska, and California. The samples were analyzed for 21 insecticides, 18 herbicides, three fungicides, and 40 pesticide degradates. Data from all sites combined show that 7 of the 10 most frequently detected pesticides were herbicides, with atrazine (70%) and metolachlor (83%) detected at every site. Dacthal, acetochlor, simazine, alachlor, and pendimethalin were detected in more than 50% of the samples. Chlorpyrifos, carbaryl, and diazinon were the only insecticides among the 10 most frequently detected compounds. Of the remaining pesticide parent compounds, 18 were detected in fewer than 30% of the samples, and 13 were not detected. The most frequently detected degradates were deethylatrazine; the oxygen analogs (OAs) of the organophosphorus insecticides chlorpyrifos, diazinon, and malathion; and 1-napthol (degradate of carbaryl). Deethylatrazine was detected in nearly 70% of the samples collected in Maryland, Indiana, and Nebraska but was detected only once in California. The OAs of chlorpyrifos and diazinon were detected primarily in California. Degradates of the acetanilide herbicides were rarely detected in rain, indicating that they are not formed in the atmosphere or readily volatilized from soils. Herbicides accounted for 91 to 98% of the total pesticide mass deposited by rain except in California, where insecticides accounted for 61% in 2004. The mass of pesticides deposited by rainfall was estimated to be less than 2% of the total applied in these agricultural areas.     

Environmental assessment in countries in transition: evolution in a changing context

Over the last fifteen years, Environmental Assessment systems of transitional societies of Central and Eastern Europe and Central Asia have undergone dramatic change from appraisals integrated into centrally planned economies to formal procedures aimed to ensure interdisciplinary analysis of environmental impacts and linked to publicly accountable decision-making. In most Central European nations, EA systems have been radically reformed to approximate the procedures used in developed countries, particularly in the European Union. In contrast, EA in most of the former Soviet republics has been reformed more gradually and is still based on the so-called State Environmental Review procedure inherited from the USSR and substantially different from 'Western' EA. About one-third of the transitional countries (in the Balkans, the Caucasus and Central Asia) have, so far, failed to establish functioning EA systems. Throughout the region, there has been a gap between EA legislation and practice, especially concerning interdisciplinary analysis of environmental impacts, public participation, and utilisation of EA findings in decision-making. A key driving force in the reform of EA systems has been the change in their societal context, the so-called 'process of transition'. Three main policy agendas--environmental protection, reforms of decision-making, and conforming to international requirements--along with the institutional context of EA regulations and practice have influenced both the change of EA systems over time and the regional variations in the patterns of their evolution. This study suggests that an effective reform of an EA system should be context-sensitive, or be 'in gear' with the political and economic transition. Future EA research should consider their changing societal contexts and focused on practical effects of applying EA procedures.     

电催化氧化处理难降解废水技术研究进展

电催化氧化处理难降解废水技术已得到了广泛关注.本文从电极材料与应用,电极结构及反应器形状,以及与其它处理方法联用等综述了最新研究进展,并在此基础上总结出了电催化氧化技术今后的发展方向.     

Community-company relations in gold mining in Ghana

As a result of Structural Adjustment Programme from the 1980s, many developing countries have experienced an increase in resource extraction activities by international and transnational corporations. The work reported here examines the perceived impacts of gold mining at the community level in the Wassa West District of Ghana, Africa and discusses those perceived impacts in the context of globalization processes and growing multinational corporate interest in Corporate Social Responsibility (CSR). Interview data compared community members' perceptions with those of company representatives in three communities. The results indicate that communities held companies responsible for a series of economic, social, and environmental changes. While recognizing some of the benefits brought by the mines, communities felt that the companies did not live up to their responsibility to support local development. Companies responded by denying, dismissing concerns, or shifting blame. Findings from this work show that lack of engagement and action by government agencies at all levels resulted in companies acting in a surrogate governmental capacity. In such situations, managing expectations is key to community-company relations.     

Sustainability Appraisal in neighbourhood planning in England

The preparation of strategic environmental assessment (SEA) inclusive sustainability appraisals (SAs) for neighbourhood plans (NPs) in England may be required when significant environmental effects are expected to arise from an NP. In this paper, we report on the result of a Ph.D. project, conducted between 2012 and 2015, in which all 15 NP SEA inclusive SAs that had been completed at the time were evaluated. In this context, the quality of SA practice was found to differ substantially. SAs were prepared either ‘in-house’ (i.e. by neighbourhood planning steering groups) or by consultants. The quality of SAs was found to be associated with their overall perceived degree of influence on the underlying NPs. Whilst the focus of this paper is on practice in England, findings are expected to be of interest to a wider international audience, in particular to those experimenting with voluntary neighbourhood/local level plan SA/SEA.     

Private participation in isolated grids in Mozambique

This article presents a case study from Mozambique of the electrification of two selected towns under a World Bank financed project. Low-cost electricity services were extended to the two isolated areas after an enabling framework had been created for private sector participation. The World Bank project also demonstrates that the private sector can be attracted to participate in rural electrification schemes even in a poor country. The example shown in this article is one of the few of its kind in SubSaharan Africa.     

我国城市生态评价研究进展

城市建设带来了越来越多的生态环境问题,生态城市建设是解决这些问题的良好途径。生态城市的建设要有一定的评价体系作为支撑,本文综述了国内基于AHP方法建立的应用较为广泛的城市生态评价体系和方法,并对国内城市生态评价的现状做了分析。