China has experienced an unprecedented urbanization and industrialization in the past decades. In this research, we examined the dynamics of construction lands and impervious surface areas (ISA) based on land use/cove...China has experienced an unprecedented urbanization and industrialization in the past decades. In this research, we examined the dynamics of construction lands and impervious surface areas (ISA) based on land use/cover change and ISA datasets between 2000 and 2008, which were provided by the national resources and environmental remote sensing information platform. The results indicated that the construction areas and ISA increased by 3468.30 and 2212.24 km 2 /a in this period primarily due to the implementation of national macro-development strategies and fast-growing economy. In 2008, ISA accounted for 0.86% of the total land area in China. Urban land areas increased by 43.46% between 2000 and 2008. The annual growth rate of 1788.22 km 2 /a in this period was 2.18 times that in the 1990s. In particular, urban ISA increased by 53.30% between 2000 and 2008 with an annual growth rate of 1348.85 km 2 /a. During the 8 years, the ISA in China increased rapidly, especially in the Beijing-Tianjin-Tangshan Metropolitan Region, Pearl River Delta, Yangtze River Delta, and the western China region. The increasing ISA may influence potentially water environmental quality in the major basins. In particular, the number of subbasins having ISA of greater than 10% increased considerably, which were primarily distributed in the Haihe River, Yangtze River and Pearl River basins. In 2008, 14.42% of the basin areas were affected by the increased ISA.展开更多
The pollutant loads of surface runoff in an urban tourist area have been investigated for two years in the Wuhan City Zoo, China. Eight sampling sites, including two woodlands, three animal yards, two roofs and one ro...The pollutant loads of surface runoff in an urban tourist area have been investigated for two years in the Wuhan City Zoo, China. Eight sampling sites, including two woodlands, three animal yards, two roofs and one road, were selected for sampling and study. The results indicate that pollutants ranked in a predictable order of decreasing load （e.g. animal yard〉roof〉woodland〉road）, with animal yards acting as the key pollution source in the zoo. Pollutants were transported mainly by particulate form in runoff. Particulate nitrogen and particulate phosphorous accounted on average for 61%, 78% of total pollutant, respectively, over 13 monitored rainfall events. These results indicate the treatment practices should be implemented to improve particulate nutrient removal. Analysis of the M（V） curve indicate that no first flush effect existed in the surface runoff from pervious areas （e.g. woodland, animal ground yard）, whereas a first flush effect was evident in runoff from impervious surfaces （e.g. animal cement yard, roof, road）.展开更多
The mapping of impervious surface area(ISA) and urban green space(UGS) is essential for improving the urban environmental quality toward ecological, livable, and sustainable goals. Currently, accurate ISA and UGS prod...The mapping of impervious surface area(ISA) and urban green space(UGS) is essential for improving the urban environmental quality toward ecological, livable, and sustainable goals. Currently, accurate ISA and UGS products are lacking in urban areas at the global scale. This study established regression models that estimated the fraction of ISA/UGS in global 30 cities for validation using MODIS NDVI and DMSP/OLS nighttime light imageries. A global dataset of ISA and UGS fraction with a spatial resolution of 250 m×250 m was developed using the regression model, with a mean relative error of 0.19 for its ISA. The results showed the global urban area of 76.29×10~4 km^2, which was primarily distributed in central Europe, eastern Asia,and central and eastern North America. The urban land area in North America, Europe, and Asia was 66.3×10~4 km^2, accounting for 86.91% of the world’s urban area;the urban land area of the top 50 countries accounted for 59.32% of the total urban land area in the world. The global ISA of 45.26×10~4 km^2 was mainly distributed in central and southern North America, eastern Asia, and Europe, as well as coastal regions around the world. The proportion of ISA situated in built-up areas on the continental scale followed the order of Africa(>70%)>South America>Oceania>Asia(>60%)>North America>Europe(>50%), and these areas were mostly in southeastern North America, southwestern Europe, and eastern and western Asia. North America, Europe, and Asia accounted for 89.44% of the world’s total UGS. The cities of developed countries in Europe and North America exposed a dramatic mosaic of ISA and UGS composites in urban construction. Therefore, the proportion of UGS is relatively high in those cities. However, in developing and underdeveloped countries, the proportion of UGS in built-up areas is relatively low, and urban environments need to be improved for livability.展开更多
Urban land cover has major impacts on a city＇s ecosystem services and the inherent quality of its urban residential environment. The spatio-temporal distribution of impervious surface area and green areas in Chinese ...Urban land cover has major impacts on a city＇s ecosystem services and the inherent quality of its urban residential environment. The spatio-temporal distribution of impervious surface area and green areas in Chinese cities has exhibited a significantly marked difference in comparison with USA cities. This study focused on monitoring and comparing the spatio-temporal dynamics, land cover patterns and characteristics of functional regions in six Chinese （n=3） and USA （n=3） cities. The study data were collated from Landsat TM/MSS imagery during the period 1978-2010. Results indicate that Chinese cities have developed compactly over the past three decades, while development has been notably dispersed among USA cities. Mean vegetation coverage in USA cities is approximately 2.2 times that found amongst Chinese urban agglomerations. Land use types within Chinese cities are significantly more complex, with a higher density of impervious surface area. Conversely, the central business district （CBD） and residential areas within USA cities were compdsed of a lower proportion of impervious surface area and a higher proportion of green land. Results may be used to contribute to future urban planning and administration efforts in both China and the USA.展开更多
The change of impervious surface area(ISA) can effectively reveal the gradual process of urbanization and act as a key index for monitoring urban expansion. Experiencing rapid growth of the built environment in the 20...The change of impervious surface area(ISA) can effectively reveal the gradual process of urbanization and act as a key index for monitoring urban expansion. Experiencing rapid growth of the built environment in the 2000 s, urban expansion of Beijing has not been fully characterized through ISA. In this study, Landsat TM images of Beijing in 2001 and 2009 were obtained, and the eight-year urban expansion process in Beijing was analyzed using the ISA extracted by means of the vegetation-imperious surface-soil(V-I-S) model. From the spatial variation in ISA, the ring structure of urban expansion in Beijing was significant during the study period, with decreasing urban density from the city center to the periphery. In the ring road analysis, the most dramatic changes of ISA were found between the fifth ring and the sixth ring. This area has experienced the most new residential development, and is currently the main source of urban expansion. The typical profile lines revealed the directional characteristics of urban expansion. The east-west profile was the most urbanized axes in Beijing, while ISA change in the east-north profile was more significant than in the other five profiles. Moreover, the transition matrix of ISA levels revealed an increase in urban density in the low density built areas; the Moran′s I index showed a clear expansion of the central urban area, which spread contiguously; and the standard deviational ellipse indicated the northeast was the dominant direction of urban expansion. These findings can provide important spatial control guidelines in the next round of national economic and social development planning, overall urban and rural planning, and land use planning.展开更多
Impervious surface area(ISA)is an important parameter for many environmental or socioeconomic relevant studies.The unique characteristics of remote sensing data made it the primary data source for ISA mapping at vario...Impervious surface area(ISA)is an important parameter for many environmental or socioeconomic relevant studies.The unique characteristics of remote sensing data made it the primary data source for ISA mapping at various scales.This paper summarizes general ISA mapping procedure and major techniques and discusses impacts of scale issues on selection of remote sensing data and corresponding algorithms.Previous studies have indicated that ISA mapping remains a challenge,especially in urban–rural frontiers and in covering a large area.Effectively employing rich spatial information in high spatial resolution imagery through texture and objectbased methods is valuable.Data fusion of multi-resolution images and spectral mixture analysis are common approaches to reduce the mixed pixel problem in medium spatial resolution images such as Landsat.Coarse spatial resolution images such as MODIS and DMSP-OLS are valuable for national and global ISA mapping but more research is needed to effectively integrate multisource/scale data for improving mapping performance.Development of an optimal procedure corresponding to specific study areas and purposes is required to generate accurate ISA mapping results.展开更多
基金supported by the Young Scientist Fund of National Natural Science Foundation of China (40901224)the National Basic Research Program of China (2010CB950900)+2 种基金the National Water Special Project(2009ZX-07207-011)the National Key Technology R&D Program(2012BAJ15B02)the National High-Tech R&D Program of China(2009AA122002)
文摘China has experienced an unprecedented urbanization and industrialization in the past decades. In this research, we examined the dynamics of construction lands and impervious surface areas (ISA) based on land use/cover change and ISA datasets between 2000 and 2008, which were provided by the national resources and environmental remote sensing information platform. The results indicated that the construction areas and ISA increased by 3468.30 and 2212.24 km 2 /a in this period primarily due to the implementation of national macro-development strategies and fast-growing economy. In 2008, ISA accounted for 0.86% of the total land area in China. Urban land areas increased by 43.46% between 2000 and 2008. The annual growth rate of 1788.22 km 2 /a in this period was 2.18 times that in the 1990s. In particular, urban ISA increased by 53.30% between 2000 and 2008 with an annual growth rate of 1348.85 km 2 /a. During the 8 years, the ISA in China increased rapidly, especially in the Beijing-Tianjin-Tangshan Metropolitan Region, Pearl River Delta, Yangtze River Delta, and the western China region. The increasing ISA may influence potentially water environmental quality in the major basins. In particular, the number of subbasins having ISA of greater than 10% increased considerably, which were primarily distributed in the Haihe River, Yangtze River and Pearl River basins. In 2008, 14.42% of the basin areas were affected by the increased ISA.
基金Project supported by the National Hi-Tech Research and Development Program (863) of China (No. 2002AA601022)
文摘The pollutant loads of surface runoff in an urban tourist area have been investigated for two years in the Wuhan City Zoo, China. Eight sampling sites, including two woodlands, three animal yards, two roofs and one road, were selected for sampling and study. The results indicate that pollutants ranked in a predictable order of decreasing load （e.g. animal yard〉roof〉woodland〉road）, with animal yards acting as the key pollution source in the zoo. Pollutants were transported mainly by particulate form in runoff. Particulate nitrogen and particulate phosphorous accounted on average for 61%, 78% of total pollutant, respectively, over 13 monitored rainfall events. These results indicate the treatment practices should be implemented to improve particulate nutrient removal. Analysis of the M（V） curve indicate that no first flush effect existed in the surface runoff from pervious areas （e.g. woodland, animal ground yard）, whereas a first flush effect was evident in runoff from impervious surfaces （e.g. animal cement yard, roof, road）.
基金supported by the Major Projects of the National Natural Science Foundation of China(Grant No.41590842)the Strategic Priority Research Program of the Chinese Academy of Sciences,Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)(Grant No.XDA20040400)the National High Technology Research and Development Program of China(Grant No.2013AA122802)
文摘The mapping of impervious surface area(ISA) and urban green space(UGS) is essential for improving the urban environmental quality toward ecological, livable, and sustainable goals. Currently, accurate ISA and UGS products are lacking in urban areas at the global scale. This study established regression models that estimated the fraction of ISA/UGS in global 30 cities for validation using MODIS NDVI and DMSP/OLS nighttime light imageries. A global dataset of ISA and UGS fraction with a spatial resolution of 250 m×250 m was developed using the regression model, with a mean relative error of 0.19 for its ISA. The results showed the global urban area of 76.29×10~4 km^2, which was primarily distributed in central Europe, eastern Asia,and central and eastern North America. The urban land area in North America, Europe, and Asia was 66.3×10~4 km^2, accounting for 86.91% of the world’s urban area;the urban land area of the top 50 countries accounted for 59.32% of the total urban land area in the world. The global ISA of 45.26×10~4 km^2 was mainly distributed in central and southern North America, eastern Asia, and Europe, as well as coastal regions around the world. The proportion of ISA situated in built-up areas on the continental scale followed the order of Africa(>70%)>South America>Oceania>Asia(>60%)>North America>Europe(>50%), and these areas were mostly in southeastern North America, southwestern Europe, and eastern and western Asia. North America, Europe, and Asia accounted for 89.44% of the world’s total UGS. The cities of developed countries in Europe and North America exposed a dramatic mosaic of ISA and UGS composites in urban construction. Therefore, the proportion of UGS is relatively high in those cities. However, in developing and underdeveloped countries, the proportion of UGS in built-up areas is relatively low, and urban environments need to be improved for livability.
基金National Natural Science Foundation of China, No.41371408 National High-Tech R＆D Program of China, No.2013AA122802+2 种基金 National Basic Research Program of China, No.2010CB950900 No.2014CB954302 National Key Technology R＆D Program, No.2012BAJ15B02
文摘Urban land cover has major impacts on a city＇s ecosystem services and the inherent quality of its urban residential environment. The spatio-temporal distribution of impervious surface area and green areas in Chinese cities has exhibited a significantly marked difference in comparison with USA cities. This study focused on monitoring and comparing the spatio-temporal dynamics, land cover patterns and characteristics of functional regions in six Chinese （n=3） and USA （n=3） cities. The study data were collated from Landsat TM/MSS imagery during the period 1978-2010. Results indicate that Chinese cities have developed compactly over the past three decades, while development has been notably dispersed among USA cities. Mean vegetation coverage in USA cities is approximately 2.2 times that found amongst Chinese urban agglomerations. Land use types within Chinese cities are significantly more complex, with a higher density of impervious surface area. Conversely, the central business district （CBD） and residential areas within USA cities were compdsed of a lower proportion of impervious surface area and a higher proportion of green land. Results may be used to contribute to future urban planning and administration efforts in both China and the USA.
基金Under the auspices of Key Project of National Natural Science Foundation of China(No.41130534)
文摘The change of impervious surface area(ISA) can effectively reveal the gradual process of urbanization and act as a key index for monitoring urban expansion. Experiencing rapid growth of the built environment in the 2000 s, urban expansion of Beijing has not been fully characterized through ISA. In this study, Landsat TM images of Beijing in 2001 and 2009 were obtained, and the eight-year urban expansion process in Beijing was analyzed using the ISA extracted by means of the vegetation-imperious surface-soil(V-I-S) model. From the spatial variation in ISA, the ring structure of urban expansion in Beijing was significant during the study period, with decreasing urban density from the city center to the periphery. In the ring road analysis, the most dramatic changes of ISA were found between the fifth ring and the sixth ring. This area has experienced the most new residential development, and is currently the main source of urban expansion. The typical profile lines revealed the directional characteristics of urban expansion. The east-west profile was the most urbanized axes in Beijing, while ISA change in the east-north profile was more significant than in the other five profiles. Moreover, the transition matrix of ISA levels revealed an increase in urban density in the low density built areas; the Moran′s I index showed a clear expansion of the central urban area, which spread contiguously; and the standard deviational ellipse indicated the northeast was the dominant direction of urban expansion. These findings can provide important spatial control guidelines in the next round of national economic and social development planning, overall urban and rural planning, and land use planning.
基金The authors acknowledge supports from the Zhejiang A&F University’s Research and Development Fund-talent startup project(2013FR052)Zhejiang Provincial Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration,School of Environmental and Resource Sciences,Zhejiang A&F University and Center for Global Change and Earth Observations,Michigan State University.
文摘Impervious surface area(ISA)is an important parameter for many environmental or socioeconomic relevant studies.The unique characteristics of remote sensing data made it the primary data source for ISA mapping at various scales.This paper summarizes general ISA mapping procedure and major techniques and discusses impacts of scale issues on selection of remote sensing data and corresponding algorithms.Previous studies have indicated that ISA mapping remains a challenge,especially in urban–rural frontiers and in covering a large area.Effectively employing rich spatial information in high spatial resolution imagery through texture and objectbased methods is valuable.Data fusion of multi-resolution images and spectral mixture analysis are common approaches to reduce the mixed pixel problem in medium spatial resolution images such as Landsat.Coarse spatial resolution images such as MODIS and DMSP-OLS are valuable for national and global ISA mapping but more research is needed to effectively integrate multisource/scale data for improving mapping performance.Development of an optimal procedure corresponding to specific study areas and purposes is required to generate accurate ISA mapping results.
