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1.
The integrated application of remote sensing, geographic information system and quantitative analytical modeling can provide scientific and effective methods for monitoring and studying urban heat island, based on land surface temperature (LST) retrieved from thermal infrared channel data of sensors. In this paper, LST is retrieved from Landsat TM6 and ETM + 6 data of Shanghai central city in 1989, 1997, 2000 and 2002, by using the mono-window algorithm. Based on the data, global and local spatial autocorrelation analysis, and geostatistical methods are adopted to quantitatively describe the characteristics of spatial heterogeneity and temporal evolution of land surface thermal landscape at different scales and periods in Shanghai central city, by utilizing exploratory spatial data analysis. Results show that LST field in Shanghai central city tends to fragmentize and complicate with the development of Shanghai, and its global spatial difference becomes greater gradually. The spatial variance pattern of the change of LST field from 1997 to 2002 indicates that the dynamic change of LST presents a tendency of increase in circularity. LST declines distinctly in the districts of Puxi and Pudong near and inside the inner ring road, while it rises obviously outside the central city and near the out ring road. The extrema of temporal change in LST field have a characteristic of spatial clustering. Besides, as the city of Shanghai expands in a circular pattern as a whole, the directional difference of dynamic change of urban surface thermal landscape exists but is not very obvious.  相似文献   

2.
Assessing spatial pattern of urban thermal environment in Shanghai, China   总被引:6,自引:6,他引:0  
The aggravating urban thermal environment has considerable adverse effects on urban physical environment, energy consumption, and public health. Due to the complexity of factors contributing to the urban thermal environment, traditional statistical methods are insufficient for acquiring data and analyzing the impacts of human activities on the thermal environment, especially for identifying dominant factors. Based on thermal remote sensing imageries and Geographic Information System analysis, we assessed spatial pattern of urban thermal environment in Shanghai in 2008, and analyzed the factors contributing to the generation of urban heat island (UHI) using principal component analysis (PCA). We found that Shanghai had obvious UHI with uneven spatial pattern in 2008. Further, we identified three most important components leading to the variances of Shanghai’s UHI: the gradient from man-made to natural land cover, landscape configuration, and anthropogenic heat release. A linear model has thus been successfully constructed, implying that PCA is helpful in identifying major contributors to UHI. The findings are of significance for policy implication to urban thermal environment mitigation.  相似文献   

3.
孙伟 《湖泊科学》2012,24(1):9-16
随着发达地区经济社会的快速发展,建设用地急剧扩张,改变地表下垫面水文条件,成为导致区域水环境不断恶化的重要因素,并引发一系列的资源环境问题.为了促进资源环境与经济社会均衡发展,近年来地理学界开展了大量空间开发功能分区和适宜性分区的研究,为区域空间管理和建设用地调控提供科学依据,但是这些研究大多以单一行政区为对象,缺少流域等跨行政区的自然地理单元的分区研究,忽视了流域经济社会发展与资源环境保护的整体性.为此,本文在借鉴相关分区研究的基础上,以太湖流域为例,探讨了流域单元空间开发适宜性分区指标选择与综合评价等技术方法,将太湖流域划分为高适宜区、中等适宜区、低适宜区和不适宜区等四种类型,并采用数据包络分析方法,探讨了建设用地配置规模与空间开发适宜性的对应关系和均衡程度,据此判断流域空间开发的失衡状态.  相似文献   

4.
Urban expansion is a hot topic in land use/land cover change(LUCC) researches. In this paper, maximum entropy model and cellular automata(CA) model are coupled into a new CA model(Maxent-CA) for urban expansion. This model can help to obtain transition rules from single-period dataset. Moreover, it can be constructed and calibrated easily with several steps.Firstly, Maxent-CA model was built by using remote sensing data of China in 2000(basic data) and spatial variables(such as population density and Euclidean distance to cities). Secondly, the proposed model was calibrated by analyzing training samples,neighborhood structure and spatial scale. Finally, this model was verified by comparing logistic regression CA model and their simulation results. Experiments showed that suitable sampling ratio(sampling ratio equals the proportion of urban land in the whole region) and von Neumann neighborhood structure will help to yield better results. Spatial structure of simulation results becomes simple as spatial resolution decreases. Besides, simulation accuracy is significantly affected by spatial resolution.Compared to simulation results of logistic regression CA model, Maxent-CA model can avoid clusters phenomenon and obtain better results matching actual situation. It is found that the proposed model performs well in simulating urban expansion of China. It will be helpful for simulating even larger study area in the background of global environment changes.  相似文献   

5.
An essential part of hydrological research focuses on hydrological extremes, such as river peak flows and associated floods, because of their large impact on economy, environment, and human life. These extremes can be affected by potential future environmental change, including global climate change and land cover change. In this paper, the relative impact of both climate change and urban expansion on the peak flows and flood extent is investigated for a small‐scale suburban catchment in Belgium. A rainfall‐runoff model was coupled to a hydrodynamic model in order to simulate the present‐day and future river streamflow. The coupled model was calibrated based on a series of measured water depths and, after model validation, fed with different climate change and urban expansion scenarios in order to evaluate the relative impact of both driving factors on the peak flows and flood extent. The three climate change scenarios that were used (dry, wet winter, wet summer) were based on a statistical downscaling of 58 different RCM and GCM scenario runs. The urban expansion scenarios were based on three different urban growth rates (low, medium, high urban expansion) that were set up by means of an extrapolation of the observed trend of urban expansion. The results suggest that possible future climate change is the main source of uncertainty affecting changes in peak flow and flood extent. The urban expansion scenarios show a more consistent trend. The potential damage related to a flood is, however, mainly influenced by land cover changes that occur in the floodplain. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

6.
The inter-coupling relationship between urban economic development and the ecological environment refers to the total of interactive, inter-influenced and other non-linear relations between economic and environmental systems in the course of economic development. Taking Ürümqi, an oasis city in arid region, as an example, we collected the data of environmental quality & pollutants discharge and information on economic development in the 20 years, analyzed the correlation between the two, conducted a fitted regression with quadratic and cubic equations, and acquired 14 mathematic models that could describe the relationship between the environment and economic development. The results show that there exists a coordinated and interactive relationship between the environment and economic development. On the basis of these quantity analyses, conceptional frame model is built to explain the fundamental basis of this environmental coupling in Ürümqi city. Both a quantitative analysis of the coupling law and a good command of the internal law between them are useful for making comprehensive decisions about the environment and economic development and harmonizing the urban sustainable development.  相似文献   

7.
Urbanization in China has expanded at an unprecedented speed since the declaration of "Reform and Open Policy"and presented many challenges. Unbalanced regional development, appearance of super megacities and concomitant problems,and conflicts between urbanization and cultivated land protection are three critical problems that Chinese urbanization has to face. To develop new plans for foreseeable future urbanization in China, it is critical to understand the evolving history of cities across China. This study maps urban expansion of 60 typical Chinese cities based on large amount of remote sensing data and the labor-intensive image interpretation method, in order to understand the history of urban expansion from the 1970 s to 2013.Results showed that area of cities expanded 5.23 times compared to their area in the 1970 s. Urban expansion in China accelerated three times(1988–1996, 1999–2006, and 2009–2011) and decelerated three times(1997–1998, 2007–2008, and 2012–2013) over the 40 years. The urban area of South China expanded most significantly 9.42 times, while the urban area in Northeast China expanded only 2.37 times. The disparity among different administrative ranks of cities was even greater than(3.81 times) the differences among different regions. Super megacities have been continuously expanding at a fast rate(8.60-fold), and have not shown obvious signs of slowing down. The proportion of cultivated land among the land sources for urban expansion decreased to a small extent in the 1990 s, but cultivated land continues to be the major land source for urban expansion. Effective future urbanization needs controlling the expansion scale of large cities and reasonably developing medium and small cities, as well as balancing regional development.  相似文献   

8.
Climate-induced drought has exerted obvious impacts on land systems in northern China. Although recent reports by the Intergovernmental Panel on Climate Change (IPCC) have suggested a high possibility of climate-induced drought in northern China, the potential impacts of such drying trends on land systems are still unclear. Land use models are powerful tools for assessing the impacts of future climate change. In this study, we first developed a land use scenario dynamic model (iLUSD) by integrating system dynamics and cellular automata. Then, we designed three drying trend scenarios (reversed drying trend, gradual drying trend, and acceleration of drying trend) for the next 25 years based on the IPCC emission scenarios and considering regional climatic predictions in northern China. Finally, the impacts of drying trend scenarios on the land system were simulated and compared. An accuracy assessment with historic data covering 2000 to 2005 indicated that the developed model is competent and reliable for understanding complex changes in the land use system. The results showed that water resources varied from 441.64 to 330.71 billion m3 among different drying trend scenarios, suggesting that future drying trends will have a significant influence on water resource and socioeconomic development. Under the pressures of climate change, water scarcity, and socioeconomic development, the ecotone (i.e., transition zone between cropping area and nomadic area) in northern China will become increasingly vulnerable and hotspots for land-use change. Urban land and grassland would have the most prominent response to the drying trends. Urban land will expand around major metropolitan areas and the conflict between urban and cultivated land will become more severe. The results also show that previous ecological control measures adopted by the government in these areas will play an important role in rehabilitating the environment. In order to achieve a sustainable development in northern China, issues need to be addressed such as how to arrange land use structure and patterns rationally, and how to adapt to the pressures of climate change and socioeconomic development together.  相似文献   

9.
上海近50年气温变化与城市化发展的关系   总被引:11,自引:1,他引:10       下载免费PDF全文
根据上海地区2个气象站近50年的年均气温数据,采用回归分析、滑动平均和Mann\|Kendall检验法研究上海地区气温的年代际变化与跃变,城郊温差的年际变化;采用趋势拟合与相关分析,研究城郊温差与城市人口、GDP、能源消耗量、建成区面积和住宅竣工面积等各项城市发展指标的关系.结果表明:(1)近50年来,上海地区年均气温缓慢上升,20世纪90年代后城郊温差呈锯齿状上升趋势,若以徐家汇代表城区,奉贤代表郊区,则近50年来,城郊温差增温率为0.23℃/10a.(2)1989~1990年为上海城区气温的跃变年份,而郊区的气温跃变出现在20世纪90年代中期.(3)各项城市发展指标均与上海城郊温差有着显著的相关性,表明它们与上海城市热岛的发展关系密切,其中,住宅建设是上海城市热岛最主要的驱动因素,城市人口和经济发展也具有重要影响.  相似文献   

10.
A gravity-spatial entropy model for the measurement of urban sprawl   总被引:1,自引:0,他引:1  
Since the mid-twentieth century, most cities worldwide have undergone a rapid expansion in urban land use. Along with the expansion, several problems, such as excessive loss of prime agricultural land and increasing traffic congestion have arisen. Thus, understanding and measurements of the expansion scale and its speed are crucial to planners and officials during urban planning and management processes. To measure such geographic phenomena, Shannon first devised entropy theory, and then Batty developed it into spatial entropy. The recently developed spatial entropy model, which was used to measure urban sprawl, introduced area to represent spatial asymmetry. However, most models did not consider spatial discretization, particularly the impact of distance. This study attempted to construct an integrated gravity-spatial entropy model to delineate distance and spatial diffusion impacts on population distribution. Then, we tested the model using Shanghai’s temporal land use and community statistical data. Application results for the new gravity-spatial model show that it is a useful tool for identifying spatial and temporal variations of urban sprawl.  相似文献   

11.
China is a country with vast population and scarce arable land per capita. China’s population is more than 1.2 billion, about one-fifth of the world’s total, while the arable land area is only 0.106 hm2 per capita, less than half of the world’s average of 0.23 hm2[1]. Arable land conservation/food security has been acknowl- edged as one of the main factors affecting the sustain- able socio-economic development in China[2], which catches the special attention of many scholars at home and abr…  相似文献   

12.
The Annualized Agricultural Non‐point Source (AnnAGNPS) pollution model has been widely used to assess and predict runoff, soil erosion, sediment and nutrient loading with a geographic information system. This article presents a case study of the effect of land‐use changes on nonpoint source (NPS) pollution using the AnnAGNPS model in the Xizhi River watershed, eastern Pearl River Delta of Guangdong province, China. The land‐use changes in the Xizhi River watershed between 1998 and 2003 were examined using the multitemporal remote sensing data. The runoff, soil erosion, sediment transport and nutrient loading 1998 and 2003 were assessed using AnnAGNPS. The effects of land‐use changes on NPS were studied by comparing the simulation results of each year. Our results showed that (i) the NPS loadings increased when forest and grass land converted into paddy, orchard and farmland land, and population size and gross domestic product size as well as the usage amounts of fertilizer and pesticide in the entire watershed were firmly correlated with the NPS loadings; (ii) the land‐use change during fast urbanization in particular when other land types were converted into the development land and buildup land led to increasing of NPS pollution; and (iii) urban land expansion showed more important effects on total organic carbon (TOC) loading compared with nitrogen and phosphorus loadings. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

13.
ABSTRACT

Ballona Creek watershed in Los Angeles, California provides a unique combination of heterogeneous urban land cover, a semi-arid environment, and a large outdoor water-use flux that presents a challenge for physically-based models. We ran simulations using the Noah Land Surface Model and Parflow-Community Land Model and compared to observations of evapotranspiration (ET), runoff, and land surface temperature (LST) for the entire 11-year study period. Both models were systematically adjusted to test the impact of land cover and urban irrigation on simulation results. Monthly total runoff and ET results are greatly improved when compared to an in-situ stream gauge and meteorological tower data: from 0.64 to 0.81 for the Nash–Sutcliffe efficiency (NSE) for runoff and from a negative NSE to 0.82 for ET. The inclusion of urban irrigation in semi-arid urban environments is found to be vital, but not sufficient, for the accurate simulation of variables in the studied models.  相似文献   

14.
This case study of the Hexi Corridor, Northwestern China, utilizes statistical methods to estimate quantitatively the interaction at a regional level between climate change, ancient social developments, and political coping strategies over the past 2000 years. The data is sourced from high-resolution reconstructions of climate series(temperature and precipitation), and historical records of cultivated land, war, population, and changes in regional administrative systems. The results show that moisture conditions played a more significant role than temperature in driving land reclamation in the Hexi Corridor. Analysis also showed a negative correlation between war frequency and the area of cultivated land in the Corridor over 20-year time intervals. Population growth was found to have a significant positive correlation with the cultivated land area during the study period. The results indicate that a climate-induced decline in agricultural production and the subsequent fluctuations in population could act as a trigger for social unrest, which is especially true at the mutual decadal time-scales. However, the interaction with administrative reform also suggests that, in the face of social and economic turmoil, a reasonable administrative hierarchy could strengthen the social governance of regional government, and promote social stability and economic development at a regional level. The study substantiates this notion with empirical quantitative evidence.  相似文献   

15.
This special issue describes research arising from the megadelta project of the Asia‐Pacific‐Networks (APN), undertaken between 2004 and 2009 ( www.megadelta.ecnu.edu.cn ). Numerous delta‐coast scientists from more than 20 countries were involved in the project concerned with developing our knowledge of land–estuarine–coastal interactions in megadeltas, and with fusing this knowledge with societal development and management. Project workshops were held in Bangkok (2004), Ho Chi Minh City (2005), Dhaka (2007) and Shanghai (2008) with over 500 participants. The main objectives of the project were: (1) development of regional databases; (2) understanding of delta formation and associated fluxes between land and sea; (3) knowledge transfer and building research capacity; and (4) understanding how better social management might follow. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

16.
The Arrow–Fisher–Henry (AFH) analysis of land development under uncertainty has been conducted in a two period model. Recently, Capozza and Helsley (1990), Batabyal (1996, 1997, 2000), and others have analyzed the question of land development under uncertainty in a multi-period setting. We extend this literature by examining the role that time independent and time dependent decision rules play in the decision to develop land over time and under uncertainty. We first construct a dynamic and stochastic model of decision making in the context of land development. Next, we use this model to analyze the expected profit of a landowner when this landowner uses, respectively, time independent and time dependent decision rules. Finally, we compare and contrast the properties of time independent and time dependent decision rules and we discuss the magnitude of the premium stemming from the maintenance of temporal flexibility in decision making.  相似文献   

17.
With the excessive development of social economy, water scarcity and water environment deterioration become a common phenomenon in metropolis. As a crucial component of urban water environment system, urban lake is mainly influenced by social economic system and tourism system. In this paper, a framework for quantitatively evaluating development sustainability of urban lake was established by a multi-objective model that represented water ecological carrying capacity (WECC). And nine key indicators including population, irrigation area, tourist quantity, the average number of hotel daily reception, TP, TN, CODMn, BOD5 were chosen from urban social-economy system and natural resilience aspects, with their index weight was determined by using the Structure Entropy Weight method. Then, we took Wuhan East Lake, the largest urban lake in China as a case study, and selected five time sections including 2002, 2004, 2007, 2009 and 2012 to synthetically evaluate and comparatively analyze the dynamic change of WECC. The results showed that: firstly, the water ecological carrying capacity values of the East Lake in five time sections were 1.17, 1.07, 1.64, 1.53 and 2.01 respectively, which all exceeded 1 and increased fluctuation. The rapid growth of population and GDP lead to sharply increasing demand for water quantity. However, a large amount of the domestic sewage and industrial waste led by economic development increases pressure on ecological environment of urban lakes. Secondly, the carrying capacity of the East Lake for tourist activities was still low. The value in 2012 was only 0.22, keeping at a slowly increasing phase, which indicates that the East Lake has large opportunity and space for developing the water resource carrying capacity and could make further efforts to attract tourists. Moreover, the WECC of the East Lake was mainly affected by rapid social and economic development and water environment damage caused by organic pollutants. From the view of urban water sustainable management, we must deeply recognize the reality that water shortages and the limited carrying capacity, and dynamic assessment of WECC provides an early warning approach and control direction of water environment. For the East Lake, it is the primary target to mitigate the carrying capacity of social-economy, especially for prevention of lake area encroachment shrinking and domestic wastewater discharge.  相似文献   

18.
杨洁  许有鹏  高斌  王跃峰  徐羽  马倩 《湖泊科学》2017,29(4):827-835
以河流近域景观格局与水环境质量间的关系为研究对象,基于2001年及2010年两期土地利用类型以及7条典型河流的溶解氧、氨氮、高锰酸盐指数、总磷、总氮5项水质指标,分析城镇化下苏州市河流水质与景观格局之间的关系及其变化规律.结果表明:(1)苏州市河流水质状况总体较差,但呈现一定的好转趋势.(2)河流水质受到城镇用地、旱地及水田的综合影响,并表现出尺度效应.其中城镇用地与旱地对河流水质恶化具有明显的作用,水田则反之.2001-2010年城镇用地及水田对水质的影响程度有所减弱,旱地则增强.(3)蔓延度指数、最大面积斑块比例对河流水质呈现负相关,斑块数量、斑块密度、香农均匀度指数、香农多样性指数则与水质呈现正相关.景观格局对于水质的影响在大范围缓冲区更为显著.研究结果可为苏州水环境管理及太湖流域城市空间开发提供一定的参考依据.  相似文献   

19.
In China urban development policies (UDP) are legislated aiming to promote the cities’ socio-economic development. Urbanization, however, leads to urban expansion and land-use changes, which in turn affects the structure, function and processes of terrestrial and marine ecosystems. Rizhao City, a seaport city of China, was chosen as a case study in order to study the ecological impacts of UDP at a strategic level. Ecosystems and their components were identified and assessed. The changes of biodiversity, habitats and ecosystem services caused by the UDP of Rizhao City were examined and analyzed. We found that UDP contributes in an essential way to protect and maintain the ecosystems and their components when it comes to land-use change. Based on our analysis, ecosystems as well as ecosystem services of Rizhao City are expected to be maintained in the near future with the current UDP.  相似文献   

20.
Currently, more than half of the world’s population is living in cities. Rapid and unplanned urbanization became a common scenario in rapidly developing countries such as those in Asia. Decline in vegetation coverage and increase in local air and land surface temperatures are among the adverse effects of unplanned urban growth. We used Landsat data for the period 1991–2017 to estimate the expansion of urban areas in terms of vegetation loss and the development of small-scale urban heat islands in developing cities in Kerala state of India. For the last 27 years, unplanned urbanization in Kerala state has increased and this resulted in the enhanced loss of vegetation and, possibly, resulted in the increase in land surface temperature (LST). Our results indicate that vegetation coverage, particularly near the urban areas, has been decreased by 5.8%, 10.4%, and 9.6% in Ernakulam, Trichur, and Kozhikode districts, respectively. The land surface temperatures also have been increased during the study period. It is interesting to note that higher increase in LST and higher reduction in vegetation coverage were observed in Trichur and Kozhikode districts compared with highly populated and urbanized Ernakulam district.  相似文献   

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