首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
The study addresses population dynamics in Ghana on the urban and regional levels between 1984 and 2000. At the urban level, the development trends are analyzed for urban localities (population above 5,000) on the basis of geo-coded census data. Potential driving forces for rapid population growth related to size, location, accessibility and facility counts are examined using bivariate and multivariate analysis. An index of weighted accessibility relative to other urban localities provides significant explanation at the national level, as does initial locality size. At the regional level, population development is analyzed to provide insight into the rural–urban relations. The level of urbanization is steadily increasing but varies considerably between regions. Areas of high population growth are found in some rural areas that have a remote location relative to the large urban centers. This seems to indicate the existence of ‘frontier’ regions, i.e. areas that experience a high degree of in-migration by people aiming to undertake specific farming activities. A high proportion of the population growth in these areas appears to take place in relatively small towns. The paper concludes with a more in-depth discussion of the development characteristics of Ghana’s Western Region. This region has experienced one of the highest regional population growth rates, mainly due to its status as a ‘frontier’ for cocoa production.
Lasse Moller-JensenEmail:
  相似文献   

2.
基于高分辨率土地利用/土地覆盖数据,本文对1985～2000年期间河西地区城市土地利用变化的区域生态环境效应进行了定量分析,结果表明:1)1985～2000年期间河西地区总体生态环境质量在一定程度上维持着相对稳定,但生态环境质量改善和恶化的两种趋势并存,并在县级行政单元上表现出明显的区域分异特征,城市用地变化对区域生态环境的影响总体而言不显著;2)整个河西地区城市用地增长缓慢,表明其城市化进程缓慢.与城市用地变化有关的土地利用类型也多分布在金昌、嘉峪关、张掖、武威和酒泉5个地级市所在地区,表明这些区域的城市化过程相对活跃;3)城市用地变化对生态环境影响的空间规律表现为:使生态环境原本较差的地区生态环境质量有所增加,而使生态环境质量较好的地区生态环境质量降低;4)城镇用地与工矿用地对区域生态环境的影响表现出与城市用地总体基本一致的规律,但农村居民点则对生态环境正、负两方面影响都较为显著;5)城市用地扩展对区域生态环境的影响也体现出与城市用地总体类似的区域分异特征;而城市用地收缩的影响则与此趋势相反.  相似文献   

3.
There are few inter-African country urban analyses because of the continent’s enormous size and socioeconomic diversity, language barriers, and wide variations in national and regional urban research capacity. Nevertheless, comparative urban studies are critical in understanding contemporary African urbanization. In this comparative spatial and temporal analysis of Ghana and Kenya’s urbanization, we find that both countries are urbanizing rapidly and are faced with many common urban problems. Moreover, Ghana is more urbanized than Kenya and has a larger indigenous urban imprint and a more widely dispersed urban pattern. Besides their physiographic and population conditions, we trace these countries’ convergent and divergent urban trends to their shared but unique experiences of colonialism, nationalism and globalization.  相似文献   

4.
This paper examines the distribution characteristics of urban settlements in the Kingdom of Saudi Arabia through major dimensions such as settlement regularly, degree of primacy and polarisation at the national and geographic regional levels. The paper points out that the settlement pattern at the national level has transformed from a primate distribution during the pre-plan period (< 1970) to an intermediary distribution during the period of development planning (1970 >). At the geographical regional level the settlement distribution, however, has shown diverse pattern. While the regional settlement distribution of Western and Eastern Region have shown trends of increasing polarisation, settlements in the Northern and Southern Regions are more log-normal in character. This is explained by the increasing growth of small and intermediary towns in the Northern and Southern Regions. The paper concludes that the national trend of decreasing urban primacy, induced by the decentralised national development strategies, is less pronounced due to the absence of a balanced regional investment policy. Since the government expenditure and settlement population growth rates are not related, slow growing primate cities continue to receive a larger share of public expenditure, enabling them to retain their primacy. This calls for a balanced regional investment policy to fully realise the national strategy of regional balance and multi-polar settlement pattern.  相似文献   

5.
The paper deals with the processes of ethnic consolidation, ethnic and linguistic assimilation and inter-ethnic integration taking place in the USSR. The author shows the influence of consolidation and assimilation processes over the trends in the numerical strength of individual peoples and the resulting change in the country's ethnic composition as this is reflected in the Soviet population censuses of 1926, 1959, 1970, and 1979.  相似文献   

6.
Makki MS 《GeoJournal》1986,13(2):111-118
The aim of this paper 3s to study the development of population weights for regions and urban centres in Saudi Arabia through the period 1962–1974. In order to achieve this aim some non-parametric statistical rules have been used such as rank-size rule and the four-city index. The results show non-balanced distribution of population on both regional and urban scales. The concentration of people in urban centres is more pronounced than the concentration in regions. This is due to internal and external movement of population towards largesized urban centres. The paper recommends that the official authorities should give more consideration to economic and service development in rural and urban areas that are retreating in ranking and decreasing in population.  相似文献   

7.
Kefa M. Otiso 《GeoJournal》2005,62(1):117-128
Kenya has been promoting equitable urban and regional development since the 1970s despite the lack of a clearly formulated national urban policy or an urban and regional development policy. A key element of the country’s equitable urban and regional development effort is the promotion of secondary cities that would relieve population pressure in the countryside, help to better integrate the country’s rural and urban economies, help to reduce congestion and improve the quality of life in the metropolitan cities of Nairobi and Mombasa, and help increase the modernization spin-off which urban centers provide to the surrounding rural areas. Using recent census and economic survey data, this paper examines the current state of Kenya’s secondary cities in the context of its urban and regional development strategies. The paper finds that: (1) the country’s urban and regional development strategies have failed to work as planned largely because of insufficient devolution of power and fiscal responsibility to municipal and other local government units, (2) the country’s secondary cities are faced with immense challenges that undermine their ability to live up to expectations, (3) some of these cities have significantly grown economically over the last four decades despite immense challenges, and (4) Nairobi’s dominance of Kenya’s economy continues because of policies that unwittingly concentrate investments there. The paper concludes with strategies that could enhance the country’s urban and regional development programs and, in the process, aid the development of its secondary cities.  相似文献   

8.
Kenya has been promoting equitable urban and regional development since the 1970s despite the lack of a clearly formulated national urban policy or an urban and regional development policy. A key element of the country’s equitable urban and regional development effort is the promotion of secondary cities that would relieve population pressure in the countryside, help to better integrate the country’s rural and urban economies, help to reduce congestion and improve the quality of life in the metropolitan cities of Nairobi and Mombasa, and help increase the modernization spin-off which urban centers provide to the surrounding rural areas. Using recent census and economic survey data, this paper examines the current state of Kenya’s secondary cities in the context of its urban and regional development strategies. The paper finds that: (1) the country’s urban and regional development strategies have failed to work as planned largely because of insufficient devolution of power and fiscal responsibility to municipal and other local government units, (2) the country’s secondary cities are faced with immense challenges that undermine their ability to live up to expectations, (3) some of these cities have significantly grown economically over the last four decades despite immense challenges, and (4) Nairobi’s dominance of Kenya’s economy continues because of policies that unwittingly concentrate investments there. The paper concludes with strategies that could enhance the country’s urban and regional development programs and, in the process, aid the development of its secondary cities.  相似文献   

9.
Kuwait has been characterised by the emergence of a dominating metropolitan center in the last two decades. The new phenomenon led to severe regional imbalance because investments and development programs concentrated around the metropolitan center of Kuwait. To alleviate problems associated with such a phenomenon, to improve urban life, and to achieve regional balance, the country must plan for establishing new towns.This paper is divided into three sections. The first section identifies and discusses the major factors which contributed to the phenomenon of metropolitan dominance. The identified factors are: oil wealth, immigration and population growth, sectoral expansion, i.e. governmental services, the housing sector, commercial activities, industrial growth, and the road network. Discussions in the second section emphasized the different patterns of urban growth and expansion in Kuwait. Four patterns of urban development are identified in this section. The third sections deals with the necessity of town development in Kuwait in light of the growing phenomenon of metropolitan dominance. To evaluate the potentials of town development in the country, four major factors are stressed in this study. They are: planning, size and location, cultural aspirations, and leadership.This is a revised version of an original paper presented at the 77th Meeting of the Association of American Geographers held in Los Angeles, April 1981  相似文献   

10.
Spanning 20?years (1979?C2007), this study is the longest time series pertaining to the resident shrimp species Palaemon longirostris in a European estuary. Data from monthly faunal surveys undertaken across the middle part of the Gironde estuary from April 1979 along with data from a statistical analysis of the commercial catches throughout the entire estuary and river were considered in order to explore their inter and intra-annual variability and long-term trends. Long-term densities series as well as environmental series (salinity, discharge, temperature and NAO) were decomposed and the effects of environmental variables were also examined using statistical models (GAMs). This revealed important spatio-temporal variability and a significant overall decrease in abundance of this species in the Gironde estuary since the beginning of the 1980s. This long-term decrease in abundance corresponded significantly to long-term decreases in both discharge and the NAO index, as well a long-term increase in temperature and salinity in the middle part of the estuary. However, models showed that environmental factors explained only a small part of the variability. The upstream shift of the population highlighted in this study, probably due to the intrusion of marine waters into the middle section of the estuary, may also have contributed to its decrease in abundance. Inter-annual variability of densities was also significantly linked with inter-annual fecundity fluctuations, and a significant decrease in both mean female size and fecundity was shown for preserved samples from 1992. Moreover, the breeding period has been temporally stretched out and began earlier in more recent years, potentially due to the increase in spring temperature.  相似文献   

11.
亓月 《山东地质》2012,(9):63-65
土地是城市发展的首要基础,城市的经济、社会、环境等各个系统的运行都以土地为载体。该文通过分析近5年来莱芜市区土地利用数据动态变化,对该区域土地利用结构和趋势进行了初步探讨,并对今后该区域土地利用方向提出了相应对策。  相似文献   

12.
Shenzhen, located in South China has experienced rapid urbanization over the past three decades. This paper focuses on the urban sprawl integrating remote sensing and geographic information systems (GIS). The overlay of the urban area maps for two adjacent study years was used to generate the sprawl categories map. The three main sprawl categories of infilling sprawl, edge-expansion sprawl and outlying sprawl were calculated and analyzed in regard to their distribution and change throughout different counties during the study years. The result showed that the urban area in the study region had increased dramatically from 19.55 km2 in 1979 to 894.31 km2 in 2005. The urban area centroids over the six study years transferred from southwest to northeast from 1979 to 2005. Among the study counties, the patterns of sprawl categories were markedly distinctive over different study periods. From 1979 to 2005, Shenzhen’s chief spread was outlying sprawl. Bao’an experienced the maximum sprawl within the three study counties. The findings show that studying urban sprawl can provide a method of monitoring urban area change, which, in turn, gives us a clearer perspective of urban sprawl patterns over a longer period of time. This would prove invaluable to those researchers such as land and urban planners.  相似文献   

13.
地表水资源是维系区域生态平衡和促进经济社会发展的制约性要素,河川径流是地表水资源的主要形式,二者的丰枯变化均直接影响流域水资源管理。基于江河实测径流量资料和水资源公报资料,初步分析了1956—2018年中国主要江河实测径流量和中国十大水资源区地表水资源的变化和演变特征。结果表明:①除长江大通站外,中国主要江河代表性水文站实测年径流量均呈现下降趋势。②黄河上游唐乃亥站实测年径流量为非显著性减少趋势,黄河花园口站实测径流量呈现显著性减少趋势;1980—2000年和2001—2018年唐乃亥站实测径流量较基准期1956—1979年分别变化1.8%和-5.9%,而同时期花园口站实测径流量分别减少26.7%和41.0%。③地理分布上,黄河是中国南北地区径流变化的分水岭,黄河以南地区江河径流量为非显著性变化,黄河以北江河径流量为显著性减少趋势,特别是海河流域,实测径流量减少最为显著;21世纪以来,黄河以北河流实测径流量较1980年之前减少幅度超过25%,海河减幅高达80%以上。④1956—2018年全国地表水资源量约为27266亿m 3,较第二次全国水资源评价结果偏少122亿m 3。21世纪以来,海河、黄河、辽河地表水资源明显减少,进一步加重了区域水资源供需矛盾。  相似文献   

14.
1956—2018年中国江河径流演变及其变化特征   总被引：14，自引：2，他引：14       下载免费PDF全文
地表水资源是维系区域生态平衡和促进经济社会发展的制约性要素,河川径流是地表水资源的主要形式,二者的丰枯变化均直接影响流域水资源管理。基于江河实测径流量资料和水资源公报资料,初步分析了1956—2018年中国主要江河实测径流量和中国十大水资源区地表水资源的变化和演变特征。结果表明:① 除长江大通站外,中国主要江河代表性水文站实测年径流量均呈现下降趋势。② 黄河上游唐乃亥站实测年径流量为非显著性减少趋势,黄河花园口站实测径流量呈现显著性减少趋势;1980—2000年和2001—2018年唐乃亥站实测径流量较基准期1956—1979年分别变化1.8%和-5.9%,而同时期花园口站实测径流量分别减少26.7%和41.0%。③ 地理分布上,黄河是中国南北地区径流变化的分水岭,黄河以南地区江河径流量为非显著性变化,黄河以北江河径流量为显著性减少趋势,特别是海河流域,实测径流量减少最为显著;21世纪以来,黄河以北河流实测径流量较1980年之前减少幅度超过25%,海河减幅高达80%以上。④ 1956—2018年全国地表水资源量约为27 266亿m3,较第二次全国水资源评价结果偏少122亿m3。21世纪以来,海河、黄河、辽河地表水资源明显减少,进一步加重了区域水资源供需矛盾。  相似文献   

15.
近40年中国平均气候与极值气候变化的概述   总被引：47，自引：0，他引：47  
随着中国气象局对近50年来逐日气象观测资料的释放,人们从不同的角度对中国平均气候和极端气候的分布特征有了更多的了解.从目前研究的结果来看,这些认识需要有一个集成,即需要有一个总体的归纳和解释.通过中国近40年来的温度极值和降水极值事件的分析认识到全球增暖和区域环流异常决定着气候极值事件的分布格局.与全球增暖相联系的是:我国微量降水在空间上表现为一致的减少趋势,我国北方寒潮事件显著减少,冷夜和冷日的减少与暖夜和暖日的增多并存,以及极端强降水有增多的趋势.与东亚季风气流和西风带气流异常对应的我国有效降水在区域分布上发生了显著变化,东部季风区中的"北涝南旱"从1970年代末转型为"南涝北旱",与华南的偏干一起形成了东部季风区降水从华南、长江到华北的"-、 、-"异常分布型,但华南在1991年出现了转湿的突变;东北和西北先后从1983年和1987年前后转为暖湿气候.极端温度和极端降水趋势的空间分布与平均温度和平均降水趋势的空间分布一致.  相似文献   

16.
Two land development scenarios based on the Central Florida Regional Growth Vision projection for 2050 were used to explore the developments?? potential influence on regional climate. One scenario is a widespread suburban land development plan, and the other is a higher density urban development plan, both for the same location in central Florida. A series of simulation experiments were conducted using a regional climate model upgraded for this study to include an urban scheme. Noticeable differences in simulated regional climate patterns were found between the land development scenarios, which could potentially influence population requirements for energy and water. In our simulations, the aggregated effect of land cover changes over large suburban areas produced a more intense heat island effect than that produced by high-density urban areas.  相似文献   

17.
Olga I. Vendina 《GeoJournal》1997,42(4):349-363
Major trends of social restructuring of Moscow population and processes of intra-urban segregation are discussed. The article comprises two main parts. The first part deals with differences between the population of Moscow and that of Russia based on the main socio-economic indicators. In the second part, emphasis is placed on the urban processes of social stratification of the population on the basis of analysis of the demographic and employment patterns of the population and peculiarities of the functioning housing market. The merging of top government officials and new business elites is stressed. A conclusion is drawn about the variation of the character of urban population differentiation and its transition to a stage of property-based spatial segregation.  相似文献   

18.
József Tóth 《GeoJournal》1994,32(4):343-350
The last four decades have brought fundamental changes in Hungarian urbanization. The number of towns has increased from 54 to 166 and the number of settlements with a population over 100 000 has grown from 3 to 8, and the number of small towns with a population just over 30 000 has increased four times compared to the situation at the beginning of the century. While urban concentration has been growing, there has been a degradation of rural settlements, especially in the category of less than 500 inhabitants. This study deals with the spatial structure of Hungarian settlements, categorizing the towns according to their regional roles, population and dynamics of growth. The changes of their social and economic spheres influence their internal structures. The study attempts to summarize all the territorial, regional consequences of the recent social and economic changes that have been defining or modifying the urban development in Hungarian settlements.  相似文献   

19.
The dynamic of consolidation of urban areas in Latin America has allowed that almost 80% of the population concentrates in cities; this has produced changes in land covers and modified regional climate, propitiating the appearance of urban heat islands. The Metropolitan Area of Toluca, State of Mexico, Mexico, holds the fifth national place in population size and experiences this process, because of this, the objective is to analyze and compare the spatiotemporal characteristics of the atmospheric urban heat island obtained from data gathered from 12 urban and rural weather stations with the surface urban heat island obtained from the digital processing of four Landsat 8 images. Results show the year-round presence of night-time atmospheric urban heat islands, which reach a peak in autumn (up to 6 °C). Daytime atmospheric urban heat islands occur in summer and autumn with a maximum intensity of 4 °C. For their part, surface urban heat islands occur in spring, summer and autumn and reach maximums of 19 °C in intensity. A strong correlation was found between wetness and surface temperature (coefficient of determination, 0.8) in spring and winter. Soil wetness directly impacts the formation of weak urban heat islands in dry season, and intense ones in wet season, while the green areas and the winds affect the spatial distribution of the same.  相似文献   

20.
京津冀地区城市人居环境气候舒适性评价   总被引：4，自引：0，他引：4  
曹伟宏  王淑新 《冰川冻土》2017,39(2):435-442
京津冀地区城市聚集,目前在京津冀协同发展规划下,随着都市圈产业结构调整,各城市面临大量人口流动迁移,人居环境气候舒适性将影响人口重布。以京津冀地区13个主要城市作为研究对象,根据1951-2013年的气候资料,采用温湿指数THI和风效指数K,综合评价各城市气候舒适度,并加以对比分析。结果表明：近63 a来,本区13个城市人居气候环境舒适性较高;区内各城市气候舒适性分布特点表现为由东北向西南,舒适性呈现降低趋势,河北省内秦皇岛、唐山、廊坊、邯郸等多个城市气候舒适性均高于北京天津两大城市。以全年气候舒适程度由高到低排序：秦皇岛>唐山>廊坊、邯郸、北京 > 承德 > 张家口 > 石家庄、邢台、保定、衡水 > 沧州、天津。这将成为引导人口分流的有利因素,驱动人口高度密集区进行有序合理疏散,缓解北京天津的大城市病问题。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号