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1.
青藏高原和阿尔卑斯山山体效应的对比研究 总被引：1，自引：0，他引：1
山体效应不仅对气候产生重大影响,也对区域地理生态格局有深远影响,尤其是它对山地垂直带分布和结构类型等的影响已经为地理学家和地植物学家所认识。目前相关研究主要集中在山体效应定量化方面,缺少不同山地山体效应的对比研究,因此对山体效应的区域差异性了解不足。本文选择欧亚大陆上具有明显山体效应的两个山地青藏高原和阿尔卑斯山为研究对象,利用收集到的气象台站观测数据、林线和DEM数据以及基于MODIS地表温度估算的青藏高原和阿尔卑斯山气温数据等,通过对比分析青藏高原与阿尔卑斯山相同海拔高度上的气温以及林线分布高度等来探讨两个山地的山体效应差异性。分析结果表明青藏高原的山体效应比阿尔卑斯山更为强烈,表现为：① 由于山体效应影响,在相同海拔高度上（4500 m）,青藏高原内部气温远高于阿尔卑斯山的气温,尤其是在最热月高原内部气温比阿尔卑斯山内部气温高10~15℃,在最冷月高原内部气温比阿尔卑斯山内部气温高5~10℃。② 由于山体效应影响,青藏高原内部林线也远高于阿尔卑斯山内部林线,约高2000~3000 m。本研究将为山体效应的影响因素分析奠定基础,同时对于揭示欧亚大陆山地生态系统格局具有一定的科学意义。 相似文献
2.
基于城镇化视角的绿洲城市用水变化驱动效应分析 总被引：1，自引：1，他引：0
城镇化是驱动区域用水变化的双刃剑,既可以通过刺激生产来促进用水总量增长,也可以通过优化用水结构和提高用水效率来抑制用水总量增长。以黑河流域张掖市为例,通过构建城镇化驱动用水变化的完全分解模型,定量测度了2000-2011年张掖市人口和经济城镇化过程对用水总量和用水效率变化的驱动效应。结果表明：张掖市人口和经济城镇化过程对用水总量均具有明显的减量效应,对用水效率均具有明显的增量效应,而且与人口和经济城镇化速度高度相关。因此建议干旱区绿洲城市在水资源约束下,应将城镇化作为优化人口结构、经济结构和用水结构,提高经济效率以及用水效率,并最终实现水-生态-经济良性循环的抓手。该结论对于科学认识干旱区绿洲城市城镇化与水资源利用的关系具有一定的参考价值。 相似文献
3.
近20年来由于封山育林政策的实施和人工乔木林的大面积种植,广西森林面积大幅增加,正在经历深刻的森林转型,森林转型过程中农林交错带和森林内部的结构重组都给生态系统带来了不容忽视的扰动。本文基于2000—2016年MODIS-EVI影像数据、1∶100万地貌图和4期土地利用数据,采用变化矢量法和Sen+Mann-Kendall对广西进行森林转型背景下的森林转型路径和森林内部扰动特征分析。研究表明:自2000年以来广西森林的EVI变化强度以无变化和低变化类型为主,总体EVI上升趋势略大于下降趋势,EVI显著下降主要分布于十万大山、大瑶山、海洋山和越城岭等山地区域和桂西北的百色水利枢纽和龙滩水利枢纽周围,显著上升部分主要集中于桂中南的左江-邕江-郁江流域平原丘陵区、桂西南喀斯特区和桂东北山地区地势低平的河谷地带。广西森林面积增加的土地来源于耕地和草地,森林转型路径表现为"经济增长型"和"森林短缺型"两种路径并存,或者存在更为复杂的复合型路径。广西森林内部扰动的减少型和扰动型分布于桂西北喀斯特和桂东北山地起伏度较大的陡坡区域,增加型分布于桂中南的平原丘陵地区。由于山地陡坡区域和喀斯特地区的生态敏感性,应更多关注扰动型和减少型在桂西北和桂东北地区的集中分布问题。 相似文献
4.
城镇化过程中,人口集疏是区域空间结构演化的根本动力。基于四普、五普、六普及2015年人口抽样数据,从多维视角分析京津冀地区近25年人口空间分布特征与集疏态势,研究发现：①京津冀地区人口总体分布仍呈西南稠密而东北稀疏格局,交通干线沿线人口地理集中度高;1990—2015年区县尺度上数量差异加剧,且在空间上存在强相关性：人口热点分布呈现以京、津和沿海区域为轴的“T”形结构,冷点区域则小幅扩张呈“C”形结构;②1990—2015年,京、津两市人口集疏空间表现出明显圈层特性,且人口扩散表现“核心-边缘”特性;河北各市人口集中在市辖区,且其周边区县人口流失程度呈阶段性加重。③综合城市规模等级与行政等级视角,城市规模与行政等级挂钩,城市行政等级越高其人口规模越大,人口集聚能力越强;主体功能分区视角下,开发区人口份额在提高,生态功能区人口份额在下降;京津冀地区人口集疏空间在2010年后发生转变,向沿海地区集聚趋势突出,表现出显著临海性。 相似文献
5.
闽东南地区耕地资源动态变化及其驱动力分析 总被引：1，自引：0，他引：1
根据1997～2005年的耕地统计数据及相关的社会经济资料,分析了闽东南地区耕地资源动态变化趋势;利用SPSS软件对9个驱动因子进行主成分分析,揭示研究区耕地利用变化的驱动机制。结果表明：近10年来,闽东南地区的耕地数量总体上呈减少趋势;社会经济发展、人口增长压力、比较经济利益驱动和城市建设是研究区耕地减少的4个驱动因子,并进一步分析了这些驱动因子与耕地变化的关系。其结果将为进一步研究闽东南地区耕地变化提供借鉴,为合理利用和保护耕地、促进区域可持续发展提供科学依据。 相似文献
6.
长江三角洲人口时空格局演变及驱动因素研究 总被引：3，自引：2，他引：1
运用重心、人口密度及相对变化率、空间计量等方法，对长江三角洲人口分布格局演变、驱动因素进行研究。结果表明：① 2000—2018年人口重心迁移方向的变化，表征人口分布格局转变，而迁移速度趋缓表征了区域发展向稳态的转变；② 在人口密度分布呈现相对稳定的区域差异基础上，时空演变从2000—2012年上海、苏南显著的增加与苏中、苏北、安徽部分城市的下降，向2012—2018年部分欠发达城市人口快速增长转变。③ 空间计量回归表明，在人口集聚的“马太效应”下，驱动因素的变化主要表现为市场力量的趋强、政府影响的弱化，另一方面区域一体化的推进也带来空间溢出效应的增强。 相似文献
7.
近十五年来,美国国内移民发生了根本性变化。1970年以前,西部地区人口净移入数一直保持第一位。1970年以后,南部人口净移入数已是西部的两倍。此外,大城市地区的人口增长率明显下降。部分原因是由于大城市地区的城市中心区人口减少了,并且前几年郊区人口激增的势头也明显缓和了。 相似文献
8.
阿尔卑斯山是全世界著名的山地之一,属欧洲最主要的山地。由于它的地理位置和在经济上政治上以至科学上的重要地位,一直为世人所注目。 阿尔卑斯山地西起法国的罗讷河东岸,东到奥匈边境;北接捷克斯洛伐克境内的舒马瓦山脉和西德南部的巴伐利亚高原,南临地中海北部的利古里亚海和亚德里亚海。整个山地东西延伸1100余公里,南北最宽处约300公里,面积21万余平方公里,地跨法国、意大利、瑞士、西德、奥地利、南斯拉夫和列支敦士登等国。这些国家被统称阿尔卑斯山区国家。然而它们各自属阿尔卑斯山地的国土面积并不相同:列支敦士登为全部,奥地利达70％,瑞士约为一半,意大利和法国分别约为10％和5％,而西德和南斯拉夫则更少。 相似文献
9.
基于历史文献及统计年鉴中的人口和城市数据,采用历史时间断面方法和现代GIS空间分析方法,对过去2 000 a来（公元2—2015年）中国经济重心的变迁轨迹进行量化研究,结果表明：1）中国经济重心总体上是趋向东南迁移,唐代以前主要向西南移动,北宋以后主要向东南移动,中国经济的空间分异先以由南北差异为主,后以东西差异为主;“沈（阳）-兰（州）-西（双版纳）弧线”东南侧的经济发展过程与格局很大程度上可代表整个中国的经济发展过程与格局。2）中国经济重心变迁与其人口重心、城市重心的变迁关系十分密切,3类重心分布区域正是古称“中原”的地区,且3类重心始终位于几何中心的东部,中国东、西部的经济差异由来久远,且相对稳定。3）中国经济重心变迁受人口格局和城市格局变化的双重制约,随着时间推移,单位人口的经济当量趋于降低,单位城市的经济当量趋于上升,城市经济格局对总体经济格局的影响日益显著。 相似文献
10.
新时期我国中心城市人口城镇化特征及其空间格局 总被引：1，自引：0，他引：1
在新一轮城镇化进程中，以人力资本为核心的创新经济逐步成为推动经济增长的动力引擎，省域中心城市作为人口聚集地的功能日益凸显。人口流动倾向影响着不同规模和行政等级城市之间的城镇体系重构，选取各个省域典型城市作为重点分析对象，通过我国城市人口最新数据统计测算，揭示出近期全国城镇化发展态势与大都市区域格局变化特征。结果发现，我国人口城镇化发展态势逐渐趋于平稳，不同地区、不同规模城市对人口的吸纳能力仍存在显著差异，各类直辖市、省会城市、副省级城市在人口集聚方面表现突出，传统港口城市、工业城市、省域副中心城市的人口吸引力逐步趋弱。其中，一级城市人口吸纳能力超强，二级城市成为人口重要集聚地，三级城市人口增速趋缓，四级城市人口吸引力平稳；可将之划分为“高/低规模”“高/低增长”四种不同组合类型。同时，城市人口的增长变化和人力资本竞争，显著影响了城市区域经济发展，特别是中西部地区省域中心城市实力日益增强，人口增长强劲，进而改变了传统东中西区域经济显著分异的格局，省会城市首位度表现出“高/低位序”“高/低集中”四种不同组合分布特征，且集中于“高位序、高集中”和“低位序、低集中”两种类型，分化格局相对明显。伴随着中国大都市的不断发育成熟，其逐步成为新时代创新经济和人口集聚的引领者。 相似文献
11.
Clarke JI 《Population geography : a journal of the Association of Population Geographers of India》1982,4(1-2):1-9
Half of the world's 200 countries have less than 3.37 million inhabitants, and many of these small countries are often assumed to experience rapid demographic transition. This is true of many of the small island populations of the developing world, especially those with largely immigrant and pluralistic populations, unusual family structures, and rapid economic development. Smallness of population alone, however, is not sufficient to ensure rapid demographic transition and many small countries of mainland Africa have experienced little transition. 相似文献
12.
The period 1996-2001 has witnessed a refocusing of population growth on Sydney and Melbourne as both cities have developed significant concentrations of so-called 'new economy' jobs and taken on, to greater or lesser extents, the characteristics of global cities. The consequence of these trends, for Sydney most particularly, is population growth. This paper establishes this demographic reality by describing recent demographic trends in Sydney and possible future scenarios for Sydney's population, given differing levels of fertility, internal migration and international migration. A related future trend is also traced--that the number of households in Sydney will grow more rapidly than the population due to changes in household structure. This raises the issue of how and where these households will be accommodated, given the relative land shortage in the Sydney Statistical Division and given that there is no doubt that planners in New South Wales will be attempting to maintain and enhance Sydney's status as a global city. In sum, the paper argues that Sydney planners should be preparing for growth of around one million people in the next 20 years and a further one million in the following 30 years. To maintain that potential future residents of Sydney can be redirected to other parts of New South Wales is a vain hope. 相似文献
13.
The expansion of medium-sized cities in Brazil has increased significantly since the 80–90's decades. In that period, most of the urbanization process was represented by the agglomeration of the population in the major metropolitan areas such as São Paulo and Rio de Janeiro. Nowadays, the rural-urban movement in Brazil is predominantly affecting cities with less than 1 million inhabitants, located particularly in the Center-West and in the Semiarid Northeast regions. The city of Teresina, the capital and largest city of the Brazilian state of Piauí, is one example that has shown an accelerated process of urban development. In this context, this paper seeks to discuss the urban sprawl of Teresina over the last four decades (1974–2014), associating its trends of urban expansion and population growth with their social and environmental implications. The results of our work indicate that urban sprawl in Teresina has been continuous over the years and getting faster in the 2010–2014 period. High demographic density areas are located mostly in peripheral zones, where the low-income population dominates. The population density varies across the city, and it is far from the standard proposed by the urban legislation. Thus, urbanization in Teresina is characterized by the sprawl of its municipal boundaries, intra-urban densification and verticalization, and an increase in population, especially in areas of low-income neighborhoods. 相似文献
14.
"The authors...discuss--on the basis of census statistics and poll results--the three basic trends of Soviet migrational processes (movement to the eastern and northern regions of new development from the country's densely settled regions, mainly central European Russia; constant and sizable rural-to-urban movement; and heavy movement into the country's largest cities and republic and oblast centers), as well as the three main migrational problems (stabilization of the rural population of central European Russia; acclimatization of new settlers in the eastern regions; and activization of the native inhabitants of Central Asia)." 相似文献
15.
Rogge JR 《The Journal of geography》1982,81(5):164-174
There is every indication that Africa's population growth will remain well above the world average for the remainder of this decade and probably for the rest of this century. With the exception of the island states and parts of North Africa, fertility levels show little indication of change. This is in part a reflection of little desire for small families, as well as a consequence of limited or even restricted family planning services. Great diversity in attitudes regarding population policy prevails among African governments, ranging from extreme pronatal to committed antinatal. Even with antinatal policies, however, many African states have yet to attain any significant success in depressing their rates of growth. To date, Mauritius can be cited as the only state to have almost achieved the transition from high to low fertility. The consequence of these continuing trends is that Africa will see further increases in its youth dependency ratio. Pressures on infrastructural services will therefore increase, and the problems of generating employment will intensify. While demographic factors are by no means the only ones creating economic stress on the continent, they clearly are contributory. Unlike Asia or parts of Latin America, Africa's problem is less a matter of too many people but rather 1 of excessive growth in too short a time frame. A realistic and effective long-term population policy, therefore, is an immediate need. Several countries including Nigeria (with a pouplation of over 80 million) are experiencing a crude birth rate of 50 or more/1,000. At least 4 countries, including Kenya, are currently doubling their population in 20 years or less. With these current population trends, a demographic transition to low vital rates must assume passage through an even higher growth phase than is currently being experienced because the fall in birth rates tends to occur much later than the fall in death rates. Government population policies and the status of family planning activities are illustrated according to natal sentiments and attitudes. Trends in national vital rates and of population structures in Africa are illustrated. 相似文献
16.
Lydolph PE 《Soviet geography》1989,30(10):711-729
"Data from the preliminary results of the 1989 census and Naseleniye SSSR 1987 permit analyses of age-sex structures of the Soviet population and distributions by civil divisions of natural growth rates, total population growth, urban growth, rural growth, percent urbanization, and growths of cities. The paper complements the treatment of census results by macroregions appearing in the November 1989 issue of Soviet Geography...by summarizing trends emerging at a finer scale of analysis and providing recent background information on demographic components of population change." 相似文献
17.
The 2001 census count of Indigenous Australians produced an intercensal change in numbers that cannot be explained by demographic processes alone. Using census and vital registration data, this paper unravels the components of such change and provides new insight into Indigenous population dynamics. In particular, it establishes the first estimates of proximate determinants of fertility, and extends mortality analysis by examining the components of low Indigenous life expectancy. Results show that demographic factors account for only 69 per cent of population change. Of these components, national Indigenous fertility is found to be below replacement level, while lack of convergence between Indigenous and non-Indigenous mortality remains. As Indigenous socio-economic circumstances are spatially diverse, the paper also explores the geography of demographic processes using data for 36 ATSIC regions and capital city/balance of State classifications. This reveals continued high fertility across parts of north Australia and an indication that mortality levels are associated with degree of urban residence. 相似文献
18.
Different levels of climatic, agricultural, demographic, political and socioeconomic change have been detected in West African countries. For many years the human impact on the region was negligible, due to the low population density. However, in the last decades, demographic increase has accelerated exploitation of the natural resources and consequently the degradation of the ecosystems. Land cover degradation and landscape changes are more or less pronounced according to politic and socio-economic conditions of each country. In this study, a region located on the borderland of north Guinea-Bissau and south Senegal, is analyzed with regard to land cover and landscape trends, considering the socio-economic factors that drive them and the borderline effect. In this analysis, remote sensing data (Landsat TM, ETM+ and OLI data) were used to obtain four land cover maps for the years 1990, 2002, 2010 and 2015. The results show a similar landscape behavior in both countries, directly related to similar socio-economic practices. Forest area increase in both countries and there is a reduction in Agriculture/Bare soil areas until 2010. Main causes may be associated to the rural exodus, resulting from the conflict for independence of Casamance, which affects the borderland region of Senegal and Guinea Bissau, or to the conversion of agricultural areas into cashew orchards. In opposition, between 2010 and 2015, Forest area decrease and Agriculture/Bare soil increase, due to the recent trend of conversion of old cashew orchards into traditional fields of cereals and peanut. An increase in landscape fragmentation is observed in the period under analysis, revealing a heterogenization trend, which can be related to the adoption of similar human practices, in the last decades. 相似文献
19.
Shrinking New Orleans: Post-Katrina Population Adjustments 总被引：1，自引：0，他引：1
《Urban geography》2013,34(5):675-699
The flooding caused by hurricane Katrina in 2005 acted as a catalyst for an abrupt change of the demographic landscape of the New Orleans metropolitan area. New Orleans city proper has been a shrinking city for the last half century, but its population loss was balanced by expanding suburbs until 2005. Based on a comparison of the newly released 2010 census data with the 2000 data, this paper discusses the major population adjustments that have resulted from the disaster. Hurricane Katrina has caused the entire metropolitan area to shrink much faster than previous declines. Five years after the storm, New Orleans displays some limited signs of resilience, although the storm seems to have accelerated its population decline. Furthermore, a close examination of the available data shows us that Katrina has provoked a major change in the city's ethnic landscape. 相似文献
20.
The aim of this paper is to present a preliminary analysis of unitary authority level data from the 2001 census of population on the spatial (and, where available, temporal) patterns in proportions of Welsh speakers in Wales. In so doing we draw attention to the advantages (and limitations) of the census as a source of information on the state of the Welsh language. Although a 2 per cent increase in the percentage of Welsh speakers between 1991 and 2001 has been welcomed, several commentators have drawn attention to the change in the nature of the question asked at the 2001 census which may account for some of this increase. In this paper, we assess what is, and is not, possible to discern from the census, draw attention to other potential sources of information on the language and make some preliminary recommendations for those agencies concerned with monitoring trends in the future, both with regard to the need for more detailed language use surveys and the nature of the question included in subsequent censuses that would permit a more useful comparison of spatial and temporal trends. 相似文献