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排序方式: 共有7084条查询结果,搜索用时 582 毫秒
31.
中国城市群发育现状分析 总被引:8,自引:1,他引:8
伴随着市场经济和工业化、城市化的推进。中国城市群正在逐渐形成并快速发展。文章在对城市群概念进行讨论的基础上,选取2002年各项经济指标,从总体经济实力、人均发展水平、中心城市与县域经济发展状况诸方面,对中国各大城市群的发育状况与存在问题进行了综合对比分析,强调国家应采取以城市群为依托的“多极联动”区域发展战略。 相似文献
32.
Groundwater study using remote sensing and geographic information systems (GIS) in the central highlands of Eritrea 总被引:3,自引:1,他引:3
Remote sensing, evaluation of digital elevation models (DEM), geographic information systems (GIS) and fieldwork techniques were combined to study the groundwater conditions in Eritrea. Remote sensing data were interpreted to produce lithological and lineament maps. DEM was used for lineament and geomorphologic mapping. Field studies permitted the study of structures and correlated them with lineament interpretations. Hydrogeological setting of springs and wells were investigated in the field, from well logs and pumping test data. All thematic layers were integrated and analysed in a GIS. Results show that groundwater occurrence is controlled by lithology, structures and landforms. Highest yields occur in basaltic rocks and are due to primary and secondary porosities. High yielding wells and springs are often related to large lineaments, lineament intersections and corresponding structural features. In metamorphic and igneous intrusive rocks with rugged landforms, groundwater occurs mainly in drainage channels with valley fill deposits. Zones of very good groundwater potential are characteristic for basaltic layers overlying lateritized crystalline rocks, flat topography with dense lineaments and structurally controlled drainage channels with valley fill deposits. The overall results demonstrate that the use of remote sensing and GIS provide potentially powerful tools to study groundwater resources and design a suitable exploration plan.The online version of the original article can be found at 相似文献
33.
The increasing natural disasters, especially floods during the last quarter century, are raising the economic losses in Taiwan.
The most severe hazard in Taiwan is flooding induced by typhoons and storms in summer and autumn. By comparing the rivers
around the world, the ones in Taiwan have the steepest slopes, the largest discharge per unit drainage area, and the shortest
time of concentrations. Rapid urbanization without proper land uses managements usually worsen the flood problems. Consequently,
flood hazards mitigation has become the most essential task for Taiwan to deal with. Although the government keeps improving
flood defense structures, the flood damage grows continuously. In this article, possible flood mitigation strategies are identified
for coping with complex environmental and social decisions with flood risk involved. 相似文献
34.
Based on the high temperature data of June to August in 1961-2000 in North China, the high temperature weather processes are investigated, and a more complete data set for severe high temperature processes is created. The climatic characteristics of adverse high temperature weather in Beijing, Tianjin, Shijiazhuang, Jinan and Taiyuan are analyzed respectively. The major features of the East-Asia Subtropical High and Transformed Continental High are discussed. The outcomes indicate that the influence of both East Asia Subtropical High and Transformed Continental High on these weather events varies, by a larger margin, from one city to another over North China and they are also closely related to the relative humidity. It is found that the behaviours of East-Asia Subtropical High and Transformed Continental High are the major important systems that give rise to the summer high temperature weather over the region. Based on these findings, the 5-day, 10-day and monthly assessment models for such high impact events have been developed. The assessment outcomes prove to be useful in assessing severe high-temperature events in major cities of North China. 相似文献
35.
ABSTRACT. This study examines altitudinal residential segregation by race in 146 cities in the U.S. South. It begins by embedding the topic in recent theorizations of the social construction of nature, the geography of race, and environmental justice. Second, it focuses on how housing markets, particularly in the South, tend to segregate minorities in low‐lying, flood‐prone, and amenity‐poor segments of urban areas. It tests empirically the hypothesis that blacks are disproportionately concentrated in lower‐altitude areas using gis to correlate race and elevation by digital elevation‐model block group within each city in 1990 and 2000. The statistical results confirm the suspected trend. A map of coefficients indicates strong positive associations in cities in the interior South‐where the hypothesis is confirmed‐and an inverse relationship near the coast, where whites dominate higher‐valued coastal properties. Selected city case studies demonstrate these relationships connecting the broad dynamics of racial segregation to the particularities of individual places. 相似文献
36.
As part of a broader process of inter-urban competition, city governments have increasingly sought to 'position' themselves as centres of creativity. In these branding initiatives, culture is viewed as a tool of urban regeneration and economic development. Our paper examines the case of Commerce Design Montréal, an annual design competition run by the City of Montréal, which aims to brand Montréal as a centre of design. Commerce Design Montréal is an example of a 'fast' policy initiated by the state, but carried out by business owners and citizens. As such, it represents a downloading of the responsibility for economic development to the private or individual scale and adopts only a partial view of the varied actors and uses that are implicated in the design process. The paper considers the opportunities and challenges that this model presents for promoting design as a form of urban regeneration in a neo-liberal context. 相似文献
37.
Abstract: This paper discusses three walking tour guides prepared for the 12th International Conference of Historical Geographers. It argues that the guides are innovative in terms of format, content and ironic sensibility. It construes them as devices for re-imagining Auckland's urban heritage. 相似文献
38.
39.
龙门山是青藏高原东缘边界山脉,具有青藏高原地貌、龙门山高山地貌和山前冲积平原三个一级地貌单元。利用数字高程模式图像和裂变径迹年代测定方法研究和计算龙门山晚新生代剥蚀厚度与剥蚀速率,结果表明:3.6 Ma以来龙门山的剥蚀厚度介于1.91-2.16 km之间,剥蚀速率介于0.53-0.60 mm/a之间。在此基础上,开展了该地区岩石圈的弹性挠曲模拟,结果表明龙门山的隆升机制具有以构造缩短隆升和剥蚀卸载隆升相叠合的特点。3.6 Ma之前,龙门山的隆升与逆冲推覆构造负载有关,以构造缩短驱动的构造隆升为特色;3.6 Ma之后,龙门山的隆升与剥蚀卸载驱动的抬升有关,并以剥蚀卸载隆升为特色,进而提出了龙门山晚新生代以来的隆升机制以剥蚀成山作用为主的认识。 相似文献
40.
城市土壤环境地球化学研究--以苏州市为例 总被引:4,自引:0,他引:4
通过苏州城市环境地球化学调查工作的实施,对城市土壤环境地球化学研究的工作方法进行了初步研究。结果显示。苏州城市土壤的主要污染区域分布于东南居民生活区、西部工业区、东部木材加工厂集中区及公路干线一带;主要污染物为重金属、有机污染物多环芳烃、有机氯农药等。根据城市自然地理环境、功能分区特点和分布面积大小,确定土壤环境地球化学采样密度和测试项目是城市土壤环境地球化学研究的关键技术。 相似文献