共查询到20条相似文献，搜索用时 29 毫秒
1.
根据1993～2003年北京地区气象台站7、8月的温度资料，分析研究了近10年来北京夏季城市热岛的变化及其环境效应.结果表明：北京夏季城市热岛的水平范围扩大到近郊区和远郊区的通州，分布特征也由“单中心”转变为“多中心”；平均热岛强度呈逐渐增强趋势，在夏季出现了强热岛；北京夏季出现热岛和强热岛的天数激增，7月最大热岛强度也呈逐年上升趋势；热岛的强度和水平分布都有明显的日变化；由于热岛效应使城区增温显著，北京夏季的高温日（Tmax≥35℃）也逐年增多. 本文还指出朝阳区气象观测站由于周围高大植被的影响，观测资料已不具备城区代表性.同时也证明绿化对降低城市热岛效应是极为有效的.本文的研究成果对北京城市发展和规划有一定的科学参考价值. 相似文献
2.
利用1971～2000年北京20个气象观测站逐日４个时次（02:00、08:00、14:00、20:00）的温度资料，选取具有代表性的城区和郊区多个站点的平均值对北京城市化进程对城市热岛效应的影响、城市热岛强度的日变化和长期变化进行了研究.分析结果指出：（1）北京城市热岛强度和总人口对数呈线性相关关系，其长期变化相关系数为076；（2）北京城市建成区的范围与城市热岛影响范围呈同步变化趋势；(3)不同时次城市热岛强度的长期变化指出，北京城市热岛强度以平均每10年022℃的速率加剧，其中1999年北京热岛强度达113℃（夜间，02:00）；(4)夜间热岛强度明显大于日间.就10年平均而言, 20世纪80年代和90年代夜戒热岛强度均超过05℃；(5)一天4个时次热岛强度的季节变化趋势基本一致，均表现为冬季强、夏季弱.并且，夜间02:00时热岛最强，中午14:00时热岛最弱. 相似文献
3.
Satellite images are used extensively in studying the urban heat island (UHI) phenomenon. We evaluated the suitability of thermal infrared (TIR) data from the HJ-1B satellite for detecting UHI using a case study in Beijing. Two modified algorithms for retrieving the land surface temperature (LST) from HJ-1B data were tested. The results were compared with LST images derived from a Landsat TM thermal band and the MODIS LST output. The spatial pattern of UHI generated using HJ-1B data matched well with that produced using TM and MODIS data. Of the two algorithms, the mono-window algorithm performed better but further tests are necessary. With more frequent coverage than TM and higher spatial resolution than MODIS, the HJ-1B TIR data present a unique opportunity to study thermal environments in cities in China and neighboring countries.
相似文献4.
Satellite images are used extensively in studying the urban heat island (UHI) phenomenon. We evaluated the suitability of thermal infrared (TIR) data from the HJ-1B satellite for detecting UHI using a case study in Beijing. Two modified algorithms for retrieving the land surface temperature (LST) from HJ-1B data were tested. The results were compared with LST images derived from a Landsat TM thermal band and the MODIS LST output. The spatial pattern of UHI generated using HJ-1B data matched well with that produced using TM and MODIS data. Of the two algorithms, the mono-window algorithm performed better but further tests are necessary. With more frequent coverage than TM and higher spatial resolution than MODIS, the HJ-1B TIR data present a unique opportunity to study thermal environments in cities in China and neighboring countries. 相似文献
5.
The seasonal and interannual variations of Beijing urban heat island (UHI) are investigated in this paper using the temperature data from 1960 to 2000 at 20 meteorological stations in the Beijing region, and then the relationship between the intensity and spatial scale of UHI and Beijing urbanization indices is analyzed and discussed. Main conclusions are the followings. First, Beijing UHI shows obvious seasonal variations, and it is strongest in winter, next in spring and autumn, and least in summer. The seasonal variation of the UHI mainly occurs in the urban area. The UHI intensity at the center of Beijing is more than 0.8℃ in winter, and only 0.5℃ in summer. Second, the intensity of Beijing HUI exhibits a clear interannual warming trend with its mean growth rate (MGR) being 0.3088℃/10 a. The MGR of HUI is largest in winter, next in spring and autumn, and least in summer, and the urban temperature increase makes a major contribution to the growth of HUI intensity. Third, since the Reform and Opening, the urbanization indices have grown several ten times or even one hundred times, the intensity of HUI has increased dramatically, and its spatial scale also expanded distinctively along with the expansion of urban architectural complexes. Fourth, the interannual variation of urbanization indices is very similar with that of HUI intensity, and their linear correlation coefficients are significant at a more than 0.001 confidence level. 相似文献
6.
Spatial structure and scale feature of the atmospheric pollution source impact of city agglomeration 总被引：1，自引：0，他引：1
The spatial structure and multi-scale feature of the atmospheric pollution influence domain of Beijing and its peripheral areas (a rapidly developed city agglomeration) is dissected and analyzed in this paper on the basis of the atmospheric pollution dynamic-chemical process observation data of the urban building ensemble boundary layer of the Beijing City Air Pollution Observation Experiment (BECAPEX) in winter (February) and summer (August) 2003, and relevant meteorological elements and satellite retrieval aerosol optical depth (AOD), etc. comprehensive data with the dynamic-statistical integrated analysis of "point-surface" spatial structure. Results show that there existed significant difference in the contribution of winter/summer different pollution emission sources to the component character of atmospheric pollution, and the principal component analysis (PCA) results of statistical model also indicate that SO2 and NOX dominated in the component structure of winter aerosol particle; instead, CO and NOX dominated in summer. Surface layer atmospheric dynamic and thermal structures and various pollutant species at the upper boundary of building ensembles at urban different observational sites of Beijing in winter and summer showed an "in-phase" variation and its spatial scale feature of "influence domain". The power spectrum analysis (PSA) shows that the period spectrum of winter/summer particle concentration accorded with those of atmospheric wind field: the longer period was dominative in winter, but the shorter period in summer, revealing the impact of the seasonal scale feature of winter/summer atmospheric general circulation on the period of atmospheric pollution variations. It is found that from analyzing urban area thermal heterogeneity that the multiscale effect of Beijing region urban heat island (UHI) was associated with the heterogeneous expansion of tall buildings area. In urban atmospheric dynamical and thermal characteristic spatial structures, the turbulent scale feature of the urban boundary layer (UBL) of architectural complexes had important impact on the multi-scale feature of urban atmospheric pollution. The comprehensive analyses of the variational analysis field of Moderate Resolution Imaging Spectroradiometer (MODIS) AOD-surface PM10 under the condition of clear sky and the correlation resultant wind vector field for pollution source-tracing suggest that the emission sources for winter Beijing atmospheric pollution aerosols particle might be remotely traced to the south peripheral greater-scale spatial range of Hebei, Shandong, Tianjin, etc., and the spatial distribution of the high value area of AOD was associated with that of the high value area of resident family number (heating surface source). The backward trajectory feature of winter/ summer air particles exhibits analogous multi-scale feature, and depicts the difference in the scale feature of the pollution sources spatial distribution in different seasons. The peripheral source trajectory paths of urban atmospheric pollution (UAP) mainly come from the fixed industrial surface source or heating surface source in the outskirt of Beijing, and the diffusion and transport distance of peripheral sources in winter is larger than one in summer. The above conclusions depict the multi-scale spatial influence domain and seasonal features caused by UAP source influence and atmospheric dynamical structure. The high value area of the winter Total Ozone Mapping Spectrometer (TOMS) AOD lay in the Beijing region and its south peripheral area, an S-N zonal pattern, which reflects the dynamical effect of peripheral topographic pattern on the diffusion of regional scale atmospheric pollution sources. Study suggests that the extent of winter atmospheric pollution within the "valley" megarelief in Beijing and periphery was close related with the pollution emission sources of the south peripheral area; and the significant "anti-phase" variation feature of winter AOD and sunshine duration in Beijing and its peripheral areas, and regional scale correlation of low cloud cover, fog days, and aerosols reflects the local climatic effect of aerosol influence in this region. Besides, analysis of the impacts of atmospheric dry/wet deposition distributions within a valley-scale on the regional water body of Miyun reservoir also reveals the possible influence of the multi-scale spatial structure of summer water, soil and atmospheric pollution sources on the water quality of Miyun reservoir. 相似文献
7.
本文以超大城市上海为例,分析了近50年四季城郊温差的总体变化趋势,同时利用城市化进程中4个年份(1987、1990、1997和2004年)9个气象站的气温数据,重点研究了上海地区热岛效应的季节变化特征及年际差异.结果表明,近50年来上海城郊温差逐年显著增长,年平均热岛天数频率为86.0%,年平均热岛强度为1.17 ℃,秋季热岛频率和强度高于其他季节,累积热岛强度也最大.不同时刻热岛的特征表明,夜间热岛(2∶00,20∶00时刻)累积强度在四季都较大,在春、夏季14∶00时刻热岛累积强度较大,而在秋、冬季8∶00时刻热岛累积强度较大.进一步分析表明,热岛效应的四季差异主要在于较强热岛和强热岛出现频率的差异;秋季大气最稳定的F类型比例较高可能是热岛效应更加显著的原因之一.四个年份对比分析表明,1997年之前的三个年份,热岛效应的四季差异比较显著.之后,随着年代的推移,四季累积热岛强度逐渐趋于均化,并且夏季低强度热岛有向中强热岛和强热岛转化的趋势,一定程度上反映了夏季人为热的贡献. 相似文献
8.
9.
An EcoCity model for regulating urban land cover structure and thermal environment: Taking Beijing as an example 总被引：2，自引：0，他引：2
《中国科学:地球科学(英文版)》2017,(6)
Urban land-use/cover changes and their effects on the eco-environment have long been an active research topic in the urbanization field. However, the characteristics of urban inner spatial heterogeneity and its quantitative relationship with thermal environment are still poorly understood, resulting in ineffective application in urban ecological planning and management.Through the integration of "spatial structure theory" in urban geography and "surface energy balance" in urban climatology, we proposed a new concept of urban surface structure and thermal environment regulation to reveal the mechanism between urban spatial structure and surface thermal environment. We developed the EcoCity model for regulating urban land cover structure and thermal environment, and established the eco-regulation thresholds of urban surface thermal environments. Based on the comprehensive analysis of experimental observation, remotely sensed and meteorological data, we examined the spatial patterns of urban habitation, industrial, infrastructure service, and ecological spaces. We examined the impacts of internal land-cover components(e.g., urban impervious surfaces, greenness, and water) on surface radiation and heat flux. This research indicated that difference of thermal environments among urban functional areas is closely related to the proportions of the land-cover components.The highly dense impervious surface areas in commercial and residential zones significantly increased land surface temperature through increasing sensible heat flux, while greenness and water decrease land surface temperature through increasing latent heat flux. We also found that different functional zones due to various proportions of green spaces have various heat dissipation roles and ecological thresholds. Urban greening projects in highly dense impervious surfaces areas such as commercial, transportation, and residential zones are especially effective in promoting latent heat dissipation efficiency of vegetation, leading to strongly cooling effect of unit vegetation coverage. This research indicates that the EcoCity model provides the fundamentals to understand the coupled mechanism between urban land use structure and surface flux and the analysis of their spatiotemporal characteristics. This model provides a general computational model system for defining urban heat island mitigation, the greening ratio indexes, and their regulating thresholds for different functional zones. 相似文献
10.
在能量平衡方程中引入气溶胶的吸收和散射作用,并与三维行星边界层运动方程组相耦合,根据温度分布显式求解运动场,探讨三维行星边界层内温度、运动、气溶胶浓度分布特征.结果表明,城市人为热释放直接决定了城市热岛效应的强度,城市面积越大,城市热岛效应的强度也越强,城市面积固定时,城市越分散,城市热岛效应的强度越弱,这为城市建设多采取卫星城的方式提供了一定的理论支撑.气溶胶的散射作用要大于吸收作用,其对城市热岛效应的强度主要起削弱作用,当气溶胶浓度较大时,吸收作用更显著一些,此时城市热岛效应的强度会有一定的增强,但是幅度不大.当城市热岛效应的强度增强时,其所驱动的环流也会增强,造成城区中心气溶胶浓度略有下降. 相似文献
11.
Spatio-temporal exploratory analysis of urban surface temperature field in Shanghai, China 总被引：1，自引：0，他引：1
Xiaoyan Dai Zhongyang Guo Liquan Zhang Dan Li 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(2):247-257
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
12.
本文利用1994～2003年北京市11个气象台站的7、8月夏季常规地面观测资料，并结合中国科学院大气物理研究所325m高铁塔观测资料，分析了近10年的城市化进程对北京市夏季城市气候造成的影响. 结果表明，各气象要素变化都突现了城市化进程的影响：(1)城区相对湿度较郊区明显偏小，呈现一“干岛”特征，且相对湿度呈逐年下降趋势；(2)降水方面，近10年来，北京市的夏季降水量逐年下降非常明显；(3)平均日蒸发量和日照时数城区大于郊区；(4)虽然城区能见度明显小于郊区，但总体来讲，1999年以后，北京地区的能见度趋好；(5)地温同样存在城市热岛现象；(6)北京地区35℃以上高温天数基本呈增多趋势，且城区高温天数明显多于郊区；(7)边界层强逆温的存在有利于城市夏季强热岛的出现. 相似文献
13.
随着近10年来北京城市化步伐的加快,城市规模迅速扩大,北京三环以外的地区已由20世纪七、八十年代的城郊非均匀下垫面发展成现在粗糙复杂的城区下垫面,市区建筑物相应增多、增密和增高,导致城区地面动力学粗糙度明显增大.本文统计分析了北京325 m气象塔1994年和1997～2003年夏季平均场观测资料,结果表明:(1)在受下垫面影响最为剧烈的近地层,风向逐年趋于紊乱,现在气象塔周围近地面的流场已经具备了典型城市粗糙下垫面的流场特征;(2)近地面夏季平均风速呈现非常明显的逐年递减的趋势,而且距离地表越近,平均风速逐年递减的趋势也越为显著,这种风速逐年递减的趋势直到63 m左右才不明显,说明现在气象塔47 m以下的观测资料反映的是城市冠层的流场特征,城市冠层厚度约在47～63 m之间;(3)随着北京城市化的发展,城区近地面的平均风速存在逐年递减的趋势,但阵风并不存在相似的递减趋势,表明城市冠层的抬升对阵风的影响并不显著. 相似文献
14.
根据北京塔7层涡动系统2012年5月至2013年12月的湍流观测数据,分析了北京城区二氧化碳浓度在不同高度层次的日变化和月变化特征,并初步给出不同季节和日变化时间段内二氧化碳的浓度垂直廓线.结果表明:二氧化碳浓度整体随高度而下降;各观测层均有浓度的明显日变化,夏季最为明显,冬季相对平缓;近地层浓度直接受城市供暖、地表植被、交通运输等碳源影响,更高观测层浓度则受对流输送和天气过程影响较大;垂直方向上,冬季浓度变化范围最大,夏季层间浓度变化最明显;在一天中的任何时刻,近地面层二氧化碳浓度的日变化最低值一般出现在夏季,50m以上则出现在春季,浓度最高值总是出现在冬季;根据对二氧化碳浓度四季垂直廓线变化的分析可以看出,边界层二氧化碳浓度强烈受到碳源、下垫面植被、大气稳定度、环境温度和天气过程等因素的影响. 相似文献
15.
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
16.
ASSESSING THE SEISMIC RISK OF CITIES AT FINE-SCALE: A CASE STUDY OF HAIDIAN DISTRICT IN BEIJING,CHINA 
下载免费PDF全文
下载免费PDF全文 In order to provide practical and useful information for the disaster prevention and relief actions, it is necessary to take into account spatial differences and temporal changes of seismic risk in evaluating seismic risk at a proper temporal and spatial scale. From the perspectives of identifying spatial difference of seismic risk within the city and performing disaster relief operations, the evaluation of urban seismic risk is done in this paper at the spatial scale of 500m*500m grids for day time and night time separately. For this purpose, this paper proposes the methods for the assessment of seismic risk, establishing the correspondence relations between the population and land use, and between the floor area of buildings destroyed and casualties at more reasonable spatial and temporal scales. Taking a case study of Haidian District in Beijing using these methods, we estimate the floor area and the value of buildings destroyed and the casualties at daytime and nighttime separately at the 500m grid scale. Results show that:a total of 185, 000m2 of areas is expected to be destroyed annually in Haidian District, and the total loss of the houses is 325 million Yuan(excluding properties within the houses). During the day(night)time, 3, 159(2, 037)victims are expected to be killed and 12, 071(7, 790) injured. Destruction of buildings and loss of houses is spatially concentrated in the downtowns in the south and the industrial parks in the east. The casualties inflicted during the day and night descend from southeast to northwest, i.e. from urban core areas, urban fringes, urban outskirts, to village. Several regions suffer heavy casualties during the day, but nighttime casualties are scattered across different regions. The conclusions in this paper efficiently identify the spatial distribution of areas at the level of high and the very high seismic risk, which provides reliable decision support for identifying priority areas for pre-disaster prevention and mitigation, emergency rescue and the distribution of various relief supplies. 相似文献
17.
Urbanization influences hydrologic cycle significantly on local, regional even global scale. With urbanization the water resources demand for dense population sharpened, thus it is a great challenge to ensure water supply for some metropolises such as Beijing. Urban area is traditionally considered as the area with lower evapotranspiration (ET) on account of the impervious surface and the lower wind speed. For most remote sensing models, the ET, defined as latent heat in energy budget, is estimated as the difference between net radiation and sensible heat. The sensible heat is generally higher in urban area due to the high surface temperature caused by heat island, therefore the latent heat (i.e. the ET) in urban area is lower than that in other region. We estimated water consumption from 2003 to 2012 in Beijing based on water balance method and found that the annual mean ET in urban area was about 654 mm. However, using Surface Energy Balance System (SEBS) model, the annual mean ET in urban area was only 348 mm. We attributed this inconsistence to the impact of anthropogenic heat and quantified this impact on the basis of the night-light maps. Therefore, a new model SEBS-Urban, coupling SEBS model and anthropogenic heat was developed to estimate the ET in urban area. The ET in urban area of Beijing estimated by SEBS-Urban showed a good agreement with the ET from water balance method. The findings from this study highlighted that anthropogenic heat should be included in the surface energy budget for a highly urbanized area. 相似文献
18.
Using a water balance modelling framework, this paper analyses the effects of urban design on the water balance, with a focus on evapotranspiration and storm water. First, two quite different urban water balance models are compared: Aquacycle which has been calibrated for a suburban catchment in Canberra, Australia, and the single‐source urban evapotranspiration‐interception scheme (SUES), an energy‐based approach with a biophysically advanced representation of interception and evapotranspiration. A fair agreement between the two modelled estimates of evapotranspiration was significantly improved by allowing the vegetation cover (leaf area index, LAI) to vary seasonally, demonstrating the potential of SUES to quantify the links between water sensitive urban design and microclimates and the advantage of comparing the two modelling approaches. The comparison also revealed where improvements to SUES are needed, chiefly through improved estimates of vegetation cover dynamics as input to SUES, and more rigorous parameterization of the surface resistance equations using local‐scale suburban flux measurements. Second, Aquacycle is used to identify the impact of an array of water sensitive urban design features on the water balance terms. This analysis confirms the potential to passively control urban microclimate by suburban design features that maximize evapotranspiration, such as vegetated roofs. The subsequent effects on daily maximum air temperatures are estimated using an atmospheric boundary layer budget. Potential energy savings of about 2% in summer cooling are estimated from this analysis. This is a clear ‘return on investment’ of using water to maintain urban greenspace, whether as parks distributed throughout an urban area or individual gardens or vegetated roofs. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
19.
京津唐地区地震灾害区域宏观脆弱性变化的初步研究——空间变化 总被引：5，自引：0，他引：5
在讨论和明确地震灾害区域宏观脆弱性的含义、分析层次和描述角度的基础上,以京津唐地区和2000年为例,构建了一个由25个指标组成的描述该地区地震灾害区域宏观脆弱性的指标体系;基于该指标体系,以主成分分析作为定量分析方法中的主线,对该地区该类脆弱性空间变化的特点和规律进行了初步的定量概括和综合。结果表明:研究区地震灾害区域宏观脆弱性的空间变化主要表现为6种脆弱性模式,各模式反映的脆弱性空间差异在形式、幅度和主要驱动因素上各异;北京、天津、唐山和秦皇岛等大中城市的市区是研究区脆弱性最大的部位,大大高于全区脆弱性的平均状况,而较全区脆弱性平均状况明显小的地区则集中在京、津两地诸郊县,研究区其他地区的脆弱性状况大体围绕全区平均水平小幅波动 相似文献
20.
Remote sensing-based artificial surface cover classification in Asia and spatial pattern analysis 总被引：2，自引：0，他引：2
WenHui Kuang LiJun Chen JiYuan Liu WeiNing Xiang WenFeng Chi DengSheng Lu TianRong Yang Tao Pan AiLin Liu 《中国科学:地球科学(英文版)》2016,59(9):1720-1737
Artificial surfaces, characterized with intensive land-use changes and complex landscape structures, are important indicators of human impacts on terrestrial ecosystems. Without high-resolution land-cover data at continental scale, it is hard to evaluate the impacts of urbanization on regional climate, ecosystem processes and global environment. This study constructed a hierarchical classification system for artificial surfaces, promoted a remote sensing method to retrieve subpixel components of artificial surfaces from 30-m resolution satellite imageries(Globe Land30) and developed a series of data products of high-precision urban built-up areas including impervious surface and vegetation cover in Asia in 2010. Our assessment, based on multisource data and expert knowledge, showed that the overall accuracy of classification was 90.79%. The mean relative error for the impervious surface components of cities was 0.87. The local error of the extracted information was closely related to the heterogeneity of urban buildings and vegetation in different climate zones. According to our results, the urban built-up area was 18.18×104 km2, accounting for 0.59% of the total land surface areas in Asia; urban impervious surfaces were 11.65×104 km2, accounting for 64.09% of the total urban built-up area in Asia. Vegetation and bare soils accounted for 34.56% of the urban built-up areas. There were three gradients: a concentrated distribution, a scattered distribution and an indeterminate distribution from east to west in terms of spatial pattern of urban impervious surfaces. China, India and Japan ranked as the top three countries with the largest impervious surface areas, which respectively accounted for 32.77%, 16.10% and 11.93% of the urban impervious surface area of Asia. We found the proportions of impervious surface and vegetation cover within urban built-up areas were closely related to the economic development degree of the country and regional climate environment. Built-up areas in developed countries had relatively low impervious surface and high public green vegetation cover, with 50–60% urban impervious surfaces in Japan, South Korea and Singapore. In comparison, the proportion of urban impervious surfaces in developing countries is approaching or exceeding 80% in Asia. In general, the composition and spatial patterns of built-up areas reflected population aggregation and economic development level as well as their impacts on the health of the environment in the sub-watershed. 相似文献