基于模糊物元的城市化生态预警模型及应用   总被引：8，自引：0，他引：8  

符娟林  乔标 《地球科学进展》2008,23(9):990-995

根据模糊物元理论建立了城市化的生态预警模型,将警报级别分为无警、轻警、中警、重警和巨警5级,并从资源预警、生态预警和环境预警3个方面构建河西走廊城市化进程中的生态环境预警指标体系,设立了预警参照标准与预警界限、警灯、警度,对河西走廊进行了实证分析。结果发现,河西走廊及五大地市按照预警指数从大到小的顺序依次为：张掖市、武威市、金昌市、河西走廊、嘉峪关市和酒泉市。其中,河西走廊的生态用水比重、植被覆盖率、人均环境保护费用和万元产值工业SO2排放量的景气指数最高,处于重警状态;城市工业用地定额、城市居住用地定额、万元产值工业废水排放量和万元产值工业粉尘排放量的景气指数最低,均处于轻警状态;其它指标均处于中警状态。可见,相对于土地资源和环境污染因素而言,水资源和生态条件已经对河西走廊的城市化产生了较强的束缚作用。  相似文献   

试论我国城市发展方针   总被引：6，自引：0，他引：6  

陈雯 《地理研究》1996,15(3):16-22

在执行重重工业的发展战略和城乡分割体制的计划经济背景下,我国制定了“控制大城市规模,合理发展中等城市,积极发展小城市”的城市建设方针。但是分析表明,这一方针不能适应市场经济和对外开放形势的需要,也不符合我国人多地少、农村剩余劳动力多的国情,必须调整现有的城市发展方针,选择适宜的城市化发展道路。因此,本文就适度发展大中城市,提高城市现代化水平;加速乡村城市化,积极合理发展小城镇;以及根据不同地区的具体情况,因地制宜地指定城市化途径等方面作了探讨。  相似文献   

Geomorphic effects of rural-to-urban land use conversion on three streams in the Central Redbed Plains of Oklahoma   总被引：2，自引：1，他引：2  

Ranbir S. Kang  Richard A. Marston   《Geomorphology》2006,79(3-4):488

This research evaluates the impact of rural-to-urban land use conversion on channel morphology and riparian vegetation for three streams in the Central Redbed Plains geomorphic province (central Great Plains ecoregion) of Oklahoma. The Deep Fork Creek watershed is largely urbanized; the Skeleton Creek watershed is largely rural; and the Stillwater Creek watershed is experiencing a rapid transition from rural to urban land cover. Each channel was divided into reaches based on tributary junctions, sinuosity, and slope. Field surveys were conducted at transects in a total of 90 reaches, including measurements of channel units, channel cross-section at bankfull stage, and riparian vegetation. Historical aerial photographs were available for only Stillwater Creek watershed, which were used to document land cover in this watershed, especially changes in the extent of urban areas (impervious cover).The three streams have very low gradients (< 0.001), width-to-depth ratios < 10, and cohesive channel banks, but have incised into red Permian shales and sandstone. The riparian vegetation is dominated by cottonwoods, ash, and elm trees that provide a dense root mat on stream banks where the riparian vegetation is intact. Channels increased in width and depth in the downstream direction as is normally expected, but the substrate materials and channel units remained unchanged. Statistical analyses demonstrated that urbanization did not explain spatial patterns of changes in any variables. These three channels in the central Redbed Plains are responding as flumes during peak flows, funneling runoff and the wash-load sediment downstream in major runoff events without any effect on channel dimensions. Therefore, local geological conditions (similar bedrock, cohesive substrates and similar riparian vegetation) are mitigating the effects of urbanization.  相似文献   

国外开发欠发达地区的经验教训对中国西部城镇化的启示     

梁德阔 《云南地理环境研究》2003,15(3):55-62

美国、英国、日本、意大利、巴西等国先后对本国欠发达地区进行了开发建设。它们以城镇化为动力、大力发展城镇工业，已经取得许多成功经验，也有着深刻的教训。中国西部大开发可从国外开发欠发达地区的经验教训中受到启迪，以城镇化为增长点带动区域经济的全面发展，重视生态环境的保护和建设，加强以交通运输为重点的城镇基础设施建设，探索出西部地区城镇工业独特的发展道路，实现经济、社会和环境的可持续发展。  相似文献   

21世纪地震灾害的一些新特点   总被引：2，自引：0，他引：2  

陈颙  彭文涛  徐文立 《地球科学进展》2004,19(3):359-363

灾害定量化是地球科学、工程科学和社会经济科学的交叉领域。人口城市化是全球的发展趋势，特别在第三世界人口城市化的趋势越来越显著。和农村发生突发灾害农民可以很容易地进行自救和互救不同，城市居民对供水、供电、煤气、暖气、通讯和交通等基础设施有很大的依赖性，现代城市在抗御自然灾害方面，比过去任何时候都显得更加脆弱。通过统计，我们发现在灾害损失 L和表征社会财富的GDP之间存在着经验关系：L＝ a＋ b×GDP＋ c×GDP 2其中 a，b，c为正的常数。关系式表明，自然灾害造成的灾害增长要比GDP的增长要快。  相似文献   

Urban development and flooding in Houston Texas, inferences from remote sensing data using neural network technique   总被引：3，自引：0，他引：3  

Shuhab D. Khan 《Environmental Geology》2005,47(8):1120-1127

The effects of urban development on the natural ecosystem and its link to the increased flooding in Houston, Texas were evaluated. Houston is suitable for this type of analysis due to its 1.95 million population, large geographic area and fast growth rate. Using neural network techniques, four Landsat Thematic Mapper images were grouped into five land use classes for the period 1984 to 2003: vegetation, bare ground, water, concrete and asphalt. Results show that asphalt and concrete increased 21% in the time period 1984–1994, 39% in 1994–2000 and 114%, from 2000 to 2003, while vegetation suffered an overall decrease. When change detection data are compared with runoff ratio data, a relationship between increased runoff and urban development is apparent, which indicates increased chances of flooding. Initial results of this work are made available to the public in GIS format via internet using Arc Internet Map Server (ArcIMS) at .  相似文献   

Down to Earth: Contextualizing the Anthropocene     

《Global Environmental Change》2016

The ‘Anthropocene’ is now being used as a conceptual frame by different communities and in a variety of contexts to understand the evolving human–environment relationship. However, as we argue in this paper, the notion of an Anthropos, or ‘humanity’, as global, unified ‘geological force’ threatens to mask the diversity and differences in the actual conditions and impacts of humankind, and does not do justice to the diversity of local and regional contexts. For this reason, we interpret in this article the notion of an Anthropocene in a more context-dependent, localized and social understanding. We do this through illustrating examples from four issue domains, selected for their variation in terms of spatial and temporal scale, systems of governance and functional interdependencies: nitrogen cycle distortion (in particular as it relates to food security); ocean acidification; urbanization; and wildfires. Based on this analysis, we systematically address the consequences of the lens of the Anthropocene for the governance of social-ecological systems, focusing on the multi-level, functional and sectoral organization of governance, and possible redefinitions of governance systems and policy domains. We conclude that the notion of the Anthropocene, once seen in light of social inequalities and regional differences, allows for novel analysis of issue-based problems in the context of a global understanding, in both academic and political terms. This makes it a useful concept to help leverage and (re-)focus our efforts in a more innovative and effective way to transition towards sustainability.  相似文献   

中国东部城市土地利用变化对江南春雨影响的模拟研究     

李鑫  马红云  陆尔 《气象科学》2016,36(4):457-465

利用美国国家大气研究中心发布的较高分辨率大气环流模式CAM 5.1,进行了中国东部(20~50°N,100~125°E)城市土地利用变化对江南春雨影响的数值试验。结果显示:较中国东部无城市土地利用的试验相比,城市用地增加后,江南春雨推迟约3候建立而提前1候结束,持续时间缩短,同时降水强度减弱。进一步分析表明:东部城市土地利用增加可改变地表能量收支,使得东部大部分地区的地表增暖,导致地表感热增强,对大气的异常加热使得该区域上空等压面抬升,缩小了低层青藏高原东南侧至西太平洋间的位势梯度,使得形成江南春雨的直接原因——西南风减小,从而减少春季江南地区的降水。中国东部城市土地利用改变可能是影响近几十年江南春雨年代际变化的原因之一。  相似文献   

近年来我国城市地理学主要研究领域的新进展   总被引：16，自引：0，他引：16  

阎小培 《地理学报》1994,49(6):533-542

本文对改革开放以来中国城市地理学研究的新进展作了综述，尤其注重新领域的进展和主要观点的概括。本文涉及的主要领域包括：（１）城市化研究；（２）城市发展方针的研究；（３）城市体系研究；（４）城市内部空间结构研究。最后，在研究展望中作者指出，在社会主义市场经济体制下，应开展城市土地和住房以及国际大都市的研究。  相似文献   

广东城市化及其发展模式的选择   总被引：5，自引：2，他引：5  

朱竑  薛德升 《热带地理》2001,21(1):17-31

在阐述广东城市化发展的现状基础上，分析了广东城市化发展过程中所存在的有明显阶段性、地区发展不均衡、小城市为主的城市化及城市化滞后于工业化等特征，并探讨了广东城市化模式的选择，指出广东城市化应该根据广东发展的实际和各地差异，走一条大、中、小城市融合、协调发展的城市化道路。  相似文献