Nonprofits and park equity in Los Angeles: a promising way forward for environmental justice     

Alessandro Rigolon 《Urban geography》2013,34(7):984-1009

Disparities in park provision raise environmental and health justice concerns. With public agencies stepping back from providing environmental amenities in increasingly neoliberal urban regimes, nonprofits in the U.S. have assumed a prominent role in the parks and recreation sector. But very few studies have comprehensively assessed whether and how park nonprofits contribute to increasing or closing the equity gap in park provision. Focusing on Los Angeles, I analyze how park nonprofits operate and which demographic groups benefit from new and improved parks supported by nonprofits. Based on interviews with local practitioners and geospatial analyses, I find that nonprofits are leading a park equity movement in Los Angeles and helped address park disparities. To do so, nonprofits built diverse coalitions, leveraged complementary strengths, coalesced with public agencies, and helped generate public funds for parks. These findings show that equity-oriented nonprofits can successfully challenge the unjust outcomes of neoliberal governance.  相似文献   

Modelling spatial patterns of urban growth in Africa     

《Applied geography (Sevenoaks, England)》2013

The population of Africa is predicted to double over the next 40 years, driving exceptionally high urban expansion rates that will induce significant socio-economic, environmental and health changes. In order to prepare for these changes, it is important to better understand urban growth dynamics in Africa and better predict the spatial pattern of rural-urban conversions. Previous work on urban expansion has been carried out at the city level or at the global level with a relatively coarse 5–10 km resolution. The main objective of the present paper was to develop a modelling approach at an intermediate scale in order to identify factors that influence spatial patterns of urban expansion in Africa. Boosted Regression Tree models were developed to predict the spatial pattern of rural-urban conversions in every large African city. Urban change data between circa 1990 and circa 2000 available for 20 large cities across Africa were used as training data. Results showed that the urban land in a 1 km neighbourhood and the accessibility to the city centre were the most influential variables. Results obtained were generally more accurate than results obtained using a distance-based urban expansion model and showed that the spatial pattern of small, compact and fast growing cities were easier to simulate than cities with lower population densities and a lower growth rate. The simulation method developed here will allow the production of spatially detailed urban expansion forecasts for 2020 and 2025 for Africa, data that are increasingly required by global change modellers.  相似文献   

Urban growth and transport infrastructure interaction in Jeddah between 1980 and 2007     

《International Journal of Applied Earth Observation and Geoinformation》2013

This paper aims to use spatial statistical tools to explore the reciprocal spatial–temporal effects of transport infrastructure and urban growth of Jeddah city, a fast developing polycentric city in Saudi Arabia. Global spatial autocorrelation (Moran's I) and local indicators of spatial association (LISA) are first used to analyze the spatial–temporal clustering of urban growth and transport infrastructure from 1980 to 2007. Then, spatial regression analysis is conducted to investigate the mutual spatial–temporal effects of urban growth and transport infrastructure. Results indicate a significant positive global spatial autocorrelation of all defined variables between 1980 and 2007. LISA results also reveal a constant significant spatial association of transport infrastructure expansion and urban growth variables from 1980 to 2007. The results not only indicate a mutual spatial influence of transport infrastructure and urban growth but also reveal that spatial clustering of transport infrastructure seems to be influenced by other factors. This study shows that transport infrastructure is a constant and strong spatial influencing factor of urban growth in the polycentric urban structure that Jeddah has. Overall, this study demonstrates that exploratory spatial data analysis and spatial regression analysis are able to detect the spatial–temporal mutual effects of transport infrastructure and urban growth. Further studies on the reciprocal relationship between urban growth and transport infrastructure using the study approach for the case of monocentric urban structure cities are necessary and encouraged.  相似文献   

An Arrow-Cycle Interpretation of the Redevelopment of Stockholm's Central Business District     

Eric Clark 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):83-91

Danish Journal of Geography 95: 83–91, 1995.

The core of Stockholm's central business district, Lower Norrmalm, underwent a process of total renewal during the post-war period. This study asks if this renewal process may be interpreted as a manifestation of a logic of cyclicity inherent to the economies of regions and nations. First, time series over construction activity are presented for three geographic levels: Stockholm, the inner city and Lower Norrmalm. Then the observed booms and slumps are analyzed in the following contexts: construction activity on the national scale, transportation and urbanization, and finally, economic and spatial restructuring. Developments on Lower Norrmalm during this period seem to have been part of a regional and national building cycle, and were moulded by adaptation to transportation needs and rapid economic restructuring. But the local effects of these forces would have been very different were it not for the mediating and actively orchestrating roles assumed by local institutions.  相似文献   

城区与郊区土体湿度监测与对比分析——以南京市为例     

顾凯  施斌  唐朝生  高磊  姜洪涛 《地球科学进展》2012,27(2):185-193

由城市化进程改变的城市空间热环境对城区土体湿度产生了重要影响。为了了解城区与郊区土体湿度的差异,以南京市为例,分别在城区、郊区建立了土体湿度监测站,分析2009年6月1日至2010年6月7日南京城区、郊区地下1 m范围内裸土、草地及混凝土覆盖环境下土体湿度的时空演化特征。研究结果表明,南京城区土体湿度总体上小于郊区,存在显著的城市土体"干岛效应",年平均干岛强度为-7.4%。在时间尺度上,1月的干岛强度最小,为-2.1%;7月最大,达到-20.5%。在空间尺度上,郊区土体湿度随深度增加而增大,城区土体则无明显规律。在不同地面覆盖环境下,城区、郊区土体湿度变化规律不同:城区裸土环境下土体湿度日变化明显,而草地及混凝土下的土体湿度日变化相对较小,3种地面覆盖环境的年均土体湿度变化规律为草地(19.0%)<混凝土(26.4%)<裸土(29.5%);郊区3种地面覆盖环境下土体湿度日变化区间及变化频率均比城区大,且年均土体湿度为混凝土(27.4%)<草地(34.7%)<裸土(36.2%)。最后,分析了造成城区、郊区土体湿度差异的原因。  相似文献   

基于城镇地籍数据库建立前的数据质量检查     

张兰  范永杰  姜毅 《山东地质》2012,(6):40-43

采用MapSUV测绘和MapGIS平台建库的数据,主要有图形数据、属性数据和影像数据。在建库前根据全国和山东省第二次土地调查城镇建库标准,对每一类数据进行分析,针对其特点制定出检查的内容、方法和标准。经过检查的数据可以保证建立高质量的数据库。  相似文献   

城市热场与绿地景观相关性定量分析   总被引：10，自引：1，他引：10  

马雪梅  张友静  黄浩 《国土资源遥感》2005,16(3):10-13

首先，利用南京市Landsat7 TM6波段高增益图像亮度值和地面温度之间的关系进行定量分析，得出南京市温度分布图； 然后， 利用NDVI值和实地调绘，根据绿地密度和绿量的不同，将绿地分为密林、疏林和草本植物等类型，并对非植被地物进行分层分类； 最后，对各类地物与地面温度场进行相关性分析，并就影响这一相关性的重要因素之一 ——景观破碎度，解释和分析了该相关性。结果表明， 由于各类绿地的破碎程度不同，对地面温度的影响能力也有很大不同。  相似文献   

A Simple Energy Balance Model for Regular Building Arrays   总被引：4，自引：0，他引：4  

M.?KandaEmail author  T.?Kawai  M.?Kanega  R.?Moriwaki  K.?Narita  A.?Hagishima 《Boundary-Layer Meteorology》2005,116(3):423-443

A simple urban energy balance model for mesoscale simulations (SUMM) was tested using results from an outdoor scale-model experiment. The model geometry is assumed to be an infinitely extended regular array of uniform buildings, each of which is composed of six faces (roof, floor, and four vertical walls). The SUMM explicitly considers the three dimensionality of surface geometry and theoretically predicts the energy balance at each face without time-consuming iterations. The SUMM was compared with outdoor scale-model experiments. The simulated energy balance and surface temperatures agree well with the values measured on a reduced-scale hardware model corresponding to the numerical model geometry.  相似文献   

Numerical modelling of the turbulent flow developing within and over a 3-d building array,part iii: a istributed drag force approach,its implementation and application     

Fue-sang Lien  Eugene Yee 《Boundary-Layer Meteorology》2005,114(2):287-313

A modified k- model is used for the simulation of the mean wind speed and turbulence for a neutrally-stratified flow through and over a building array, where the array is treated as a porous medium with the drag on the unresolved buildings in the array represented by a distributed momentum sink. More specifically, this model is based on time averaging the spatially averaged Navier–Stokes equation, in which the effects of the obstacle-atmosphere interaction are included through the introduction of a distributed mean-momentum sink (representing drag on the unresolved buildings in the array). In addition, closure of the time-averaged, spatially averaged Navier–Stokes equation requires two additional prognostic equations, namely one for the time-averaged resolved-scale kinetic energy of turbulence,, and another for its dissipation rate, . The performance of the proposed model and some simplified versions derived from it is compared with the spatially averaged, time-mean velocity and various spatially averaged Reynolds stresses diagnosed from a high-resolution computational fluid dynamics (CFD) simulation of the flow within and over an aligned array of sharp-edged cubes with a plan area density of 0.25. Four different methods for diagnosis of the drag coefficient C_Dfor the aligned cube array, required for the volumetric drag force representation of the cubes, are investigated here. We found that the model predictions for mean wind speed and turbulence in the building array were not sensitive to the differing treatments of the source and sink terms in the and equations (e.g., inclusion of only the `zeroth-order' approximation for the source/sink terms compared with inclusion of a higher-order approximation for the source/sink terms in the and equations), implying that the higher-order approximations of these source/sink terms did not offer any predictive advantage. A possible explanation for this is the utilization of the Boussinesq linear stress–strain constitutive relation within the k– modelling framework, whose implicit omission of any anisotropic eddy-viscosity effects renders it incapable of predicting any strong anisotropy of the turbulence field that might exist in the building array.  相似文献   

中心地模式的实验研究——江苏省赣榆县和灌云县城镇网的优化设计   总被引：2，自引：0，他引：2  

牛亚菲 《地理学报》1989,(2)

中心地理论提供了研究城镇体系的空间布局和等级结构的方法，对农村地区集镇体系研究更具有指导意义。本文以中心地理论为基础，对江苏省赣榆县和灌云县集镇体系的基本结构、形成机制及现伏集镇体系的不合理性进行了分析，并提出了二县集镇体系布局的优化设计。  相似文献