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
To meet the demand of urban rainwater integrated management,we designed and complemented a physical simulation experimental system of urban rainfall infiltration regulation parameters.We discuss the feasibility of qua...To meet the demand of urban rainwater integrated management,we designed and complemented a physical simulation experimental system of urban rainfall infiltration regulation parameters.We discuss the feasibility of quantitative regulations of urban underlying surface rainfall infiltration conditions and a practical application of a simulated experimental system.In a com- prehensive analysis of the composition of an effective rainwater harvesting system and selection of water storage material,we simulated the major parameters of an experimental area rainfall,soil moisture and water storage capacity by providing an effective regulation of the experimental area runoff coefficient,obtained from basic data.展开更多
Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts,thereby resulting in negative effects on soil function and urban environm...Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts,thereby resulting in negative effects on soil function and urban environment.Soil samples were collected at 0-20cm depth in Nanjing City,China,in which seven sites were selected for urban open soils,and fourteen sites with similar parent material were selected for the impervious-covered soils,to examine the effect of impervious surface on soil properties and microbial activities,and to determine the most important soil properties associated with soil organic carbon(SOC)transformation in the urban soils covered by impervious surfaces.Soil organic carbon and water-soluble organic carbon(WSOC)concentrations,potential carbon(C)and nitrogen(N)mineralization rates,basal respiration,and physicochemical properties with respect to C transformation were measured.Installation of impervious surface severely affected soil physicochemical properties and microbial activities,e.g.,it significantly decreased total N contents,potential C mineralization and basal respiration rate(P<0.01),while increased pH,clay and Olsen-P concentrations.Soil organic carbon in the sealed soils at 0-20 cm was 2.35 kg m^(-2),which was significantly lower than the value of 4.52 kg m^(-2)in the open soils(P<0.05).Canonical correlation analysis showed WSOC played a major role in determining SOC transformation in the impervious-covered soil,and it was highly correlated with total N content and potential C mineralization rate.These findings demonstrate that installation of impervious surface in urban area,which will result in decreases of SOC and total N concentrations and soil microbial activities,has certain negative consequences for soil fertility and long-term storage of SOC.展开更多
Under the background of China's rapid urbanization, study on comparative analysis of the spatial structure of urban agglomerations between China and the US can provide the policy proposals of space optimization fo...Under the background of China's rapid urbanization, study on comparative analysis of the spatial structure of urban agglomerations between China and the US can provide the policy proposals of space optimization for the Chinese government. Taking the Beijing-Tianjin-Hebei(BTH) and Boswash as study area, we mapped the subpixel-level impervious surface coverage of the BTH and Boswash, respectively, from 1972 to 2011. Further, landscape metrics, gravitational model and spatial analysis were used to analyze the differences of the spatial structures between the BTH and Boswash. The results showed that(1) the area of the impervious surface increased rapidly in the BTH, while those remained stable in the Boswash.(2) The spatial structure of the BTH experienced different periods including isolated cities stage, dual-core cities stage, group cities stage and network-style cities stage, while those of the Boswash was more stable, and its spatial pattern showed a "point-axis" structure.(3) The spatial pattern of high-high assembling regions of the impervious surface exhibited a "standing pancake" feature in the BTH, while those showed a "multi-center, local aggregation and global discrete" feature in the Boswash.(4) All the percentages of the impervious surface of ecological, living, and production land of the BTH were higher than those of the Boswash. At last, from the perspective of space optimization of urban agglomeration, the development proposals for the BTH were proposed.展开更多
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Projects 40371113 supported by the National Natural Science Foundation of ChinaOF060096 by the Youth Scientific Foundation of China University of Mining & Technology
文摘To meet the demand of urban rainwater integrated management,we designed and complemented a physical simulation experimental system of urban rainfall infiltration regulation parameters.We discuss the feasibility of quantitative regulations of urban underlying surface rainfall infiltration conditions and a practical application of a simulated experimental system.In a com- prehensive analysis of the composition of an effective rainwater harvesting system and selection of water storage material,we simulated the major parameters of an experimental area rainfall,soil moisture and water storage capacity by providing an effective regulation of the experimental area runoff coefficient,obtained from basic data.
基金Surpported by the National Natural Science Foundation of China(No.41001047)
文摘Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts,thereby resulting in negative effects on soil function and urban environment.Soil samples were collected at 0-20cm depth in Nanjing City,China,in which seven sites were selected for urban open soils,and fourteen sites with similar parent material were selected for the impervious-covered soils,to examine the effect of impervious surface on soil properties and microbial activities,and to determine the most important soil properties associated with soil organic carbon(SOC)transformation in the urban soils covered by impervious surfaces.Soil organic carbon and water-soluble organic carbon(WSOC)concentrations,potential carbon(C)and nitrogen(N)mineralization rates,basal respiration,and physicochemical properties with respect to C transformation were measured.Installation of impervious surface severely affected soil physicochemical properties and microbial activities,e.g.,it significantly decreased total N contents,potential C mineralization and basal respiration rate(P<0.01),while increased pH,clay and Olsen-P concentrations.Soil organic carbon in the sealed soils at 0-20 cm was 2.35 kg m^(-2),which was significantly lower than the value of 4.52 kg m^(-2)in the open soils(P<0.05).Canonical correlation analysis showed WSOC played a major role in determining SOC transformation in the impervious-covered soil,and it was highly correlated with total N content and potential C mineralization rate.These findings demonstrate that installation of impervious surface in urban area,which will result in decreases of SOC and total N concentrations and soil microbial activities,has certain negative consequences for soil fertility and long-term storage of SOC.
基金National Natural Science Foundation of China,No.41671339
文摘Under the background of China's rapid urbanization, study on comparative analysis of the spatial structure of urban agglomerations between China and the US can provide the policy proposals of space optimization for the Chinese government. Taking the Beijing-Tianjin-Hebei(BTH) and Boswash as study area, we mapped the subpixel-level impervious surface coverage of the BTH and Boswash, respectively, from 1972 to 2011. Further, landscape metrics, gravitational model and spatial analysis were used to analyze the differences of the spatial structures between the BTH and Boswash. The results showed that(1) the area of the impervious surface increased rapidly in the BTH, while those remained stable in the Boswash.(2) The spatial structure of the BTH experienced different periods including isolated cities stage, dual-core cities stage, group cities stage and network-style cities stage, while those of the Boswash was more stable, and its spatial pattern showed a "point-axis" structure.(3) The spatial pattern of high-high assembling regions of the impervious surface exhibited a "standing pancake" feature in the BTH, while those showed a "multi-center, local aggregation and global discrete" feature in the Boswash.(4) All the percentages of the impervious surface of ecological, living, and production land of the BTH were higher than those of the Boswash. At last, from the perspective of space optimization of urban agglomeration, the development proposals for the BTH were proposed.
