Jiao S.,Capital Normal University |
Jiao S.,State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation |
Jiao S.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
Yu J.,Capital Normal University |
And 7 more authors.
Canadian Journal of Remote Sensing | Year: 2017
High-rise buildings in the modern urban setting may have a considerable impact on land subsidence. The process of urbanization in Beijing has been found to be in direct relationship with the land subsidence. The permanent scatterers interferometric aperture radar (PSInSAR) technology is becoming a conventional tool for land subsidence monitoring. Synthetic aperture radar (SAR) tomography, as an extension of PSInSAR technology, allows a full 3D imaging, and is useful to reconstruct 3D urban building maps. In this study, a SAR tomography method “scale-down by L1 norm minimization, model selection, and estimation reconstruction” (SL1MMER) was applied to 33 TerraSAR-X images to retrieve building height. The object-oriented classification method based on the support vector machine was applied on the World View 2 image to extract geometry of building footprints and to aggregate SL1MMER derived building heights for each building. The building footprints and building heights were used to calculate the volume of buildings. The Stanford method for persistent scatterers, a PSInSAR methodology, was used to obtain land subsidence rates. The correlation coefficient between the building volumes and land subsidence showed no positive relationship for buildings that were below a certain volume. However, at local scale, with the increase of the building volumes, the correlation increased. The larger the volume of buildings, the stronger the relationship became. Once the volume of buildings became larger than 3.00 × 105 m3, the impact of building volume on land subsidence remained stable. © 2017, Copyright © CASI.
Huang X.-J.,State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation |
Huang X.-J.,Chinese Academy of Geological Sciences |
Huang X.-J.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
Wu Z.-H.,Chinese Academy of Geological Sciences |
And 9 more authors.
Geological Bulletin of China | Year: 2014
In this paper, 3D visual image was constructed to interpret the distribution and geometric structure characteristics of active faults based on LANDSAT ETM+/ASTGTM data obtained in northwest Yunnan Province, and then some basin parameters which indicated the fault activities were extracted from 31 basins. Finally, the characteristics of active faults were summed up, and their activities were divided into three grades, i.e., strong, medium and weak. The results show that there exist significant difference and zoning in the faults' activities within this zone. The activity of the Lijiang-Dali and Chenghai-Binchuan faults are strong, that of the Jianch-uan-Qiaohou faults is of the medium grade, and that of the Tonggian-Weishan faults belongs to the weak grade. Strong active faults are distributed around the boundary of northwest Yunnan rift zone. In terms of the latitude, the activities of the faults in the south and the north are the strongest, whereas those in the central part are weak. In the light of the longitude, the faults' activities on both east side and west side are strong, whereas those in the central part are weak. The differences of the fault activities are on the whole consistent with historical earthquake activities.
Huili G.,State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation |
Huili G.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
Huili G.,Key Laboratory of 3 Dimensional Information Acquisition and Application |
Huili G.,Capital Normal University |
And 9 more authors.
European Space Agency, (Special Publication) ESA SP | Year: 2013
Inhalable particulate matter (IPM) is one of the principal pollutants in Beijing. Sand weather in spring and winter seasons partly because of regional airflow, in most cases it is results from autochthonic pollution, especially in heating season of winter. In this paper, the law of temporal spatial distribution of IPM and the relationship between IPM and influence factors were studied combing RS techniques with ground-based monitoring. The change of underlying surface which were obtained from high resolution Remote Sensing images in different periods was analyzed; the content of different diameter of particles were collected by ground observation instrument and chemical composition were analyzed; the relationship of distribution of IPM and underlying surface was studied using spatial analysis of GIS. The results indicate that the pollution distribution of IPM has a very close relation with underlying surface, man-made pollution sources, population density and meteorological factors.
Meng D.,State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation |
Wang M.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
Li X.,Key Laboratory of Dimensional Information Acquisition and Application |
Gong H.,Capital Normal University
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013
The urban thermal environment is an important element for the urban ecological environment, urban climate and urban disasters. This paper selected MOD11A2, the MODIS LST night data to study the thermal environment evolution in Beijing, Shanghai and Guangzhou, which are the three major cities of China in the past decade. Three methods have been applied in the paper, Landscape centroid evolution, Landscape pattern index and spatial autocorrelation. Three main conclusions have been drawn as follows. Firstly the thermal landscape distributions in the three cities have moved from the suburb to the downtown. And the evolution trend of the thermal landscape is changed from the low temperature region, sub- middle temperature region to middle temperature region, sub-high temperature region and high temperature region. Secondly, among these five types of thermal landscape, the middle temperature region is the most prevalent. The urban thermal landscape fragmentation was highest in Shanghai among the three cities, and sub-middle and high temperature region has the highest fragmentation. The urban thermal landscape dispersion was highest in Beijing, and the dispersion of low and high temperature region was higher than the other types of thermal landscapes. Thirdly, thermal environment spatial autocorrelation analysis showed that the high-high temperature zones were adjacent, low-low temperature areas were adjacent, which are the main types in the temperature spatial agglomeration. And for Beijing and Guangzhou city, the high- high temperature zone located in the south of the city, the low-low temperature region located in the north. While, the spatial autocorrelation distribution of LST in Shanghai is more complicated. The distribution areas of high-high temperature varied among the three cities in the past decade. In Beijing, the distribution area increased shortly after decreasing, and in Guangzhou, the distribution area continued to decline, which preliminary reflects the heat island effect problem aggravated in Beijing, while weakened in Shanghai and Guangzhou. Through comparisons and analysis, the paper has provided a reference for urban planning and urban living environment improvements, but there are still some inadequacies to be further studied. Firstly, this study only selected the January night LST data in the three cities. Because the time factors, such as season, daytime and nocturne, will affect the urban heat environment pattern, the comprehensiveness of the thermal environment pattern changes need to be improved. In addition, the paper only selected the data in the period of three years, the evolution regulation of the urban thermal environment pattern is not precise. Secondly, the landscape of urban heat environment were impacted by many factors, including the pattern of landuse, urban surface construction, weather conditions, terrain, anthropogenic heat emissions factors and so on. The analysis between the urban heat environment and impact factors will help reveal the mechanism of urban heat environment and which will be studied further.
Fan J.,Capital Normal University |
Fan J.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
Li X.,Capital Normal University |
Li X.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
And 8 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015
The ground subsidence phenomenon is more serious in Beijing, large-scale land subsidence seriously threats to urban planning and construction and the safety of residents. In order to study the subsidence condition, it is necessary to monitor land subsidence. Choosing 28 scenes Envisat ASAR images covering Beijing city from December 2003 to March 2009, permanent scatterer SAR interferometry (PSI) technique was applied to obtained time series land subsidence information. Then the trend characteristics and factors of subsidence were analyzed, comparing land subsidence result with the groundwater data and geological structure data. Comparison between the PSI-derived subsidence rates and leveling data obtained shows that the result of PSI is agreed with the leveling data. The results indicate that the PSI technique is capable of providing high-level accuracy subsidence information. The results show that:(1) The deformation rates derived PSI ranging from -45.80 to 4.36mm/a;(2) In the study area, the serious subsidence areas distribute in Chaoyang District, Shunyi District, Tongzhou District and Pinggu District;(3) The subsidence tends to become more and more concentrated in 6 years from 2003 to 2009. © 2015 SPIE.
Zhang L.,Capital Normal University |
Zhang L.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
Li X.J.,Capital Normal University |
Li X.J.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015
Wetlands are highly productive ecosystems and provide people with both direct and indirect benefits, which are called ecosystem services.Despite of the high value of the ecosystem services that wetlands provide to us, these continue to be degraded or lost due to the effects of intensive agricultural practices, irrigations, water extraction for domestic and industrial uses, urbanization, infrastructure and industrial development and pollution. Wetland ecosystem services have not been fully recognized or adequately quantified during the past economic and social development. Hence, accurate understanding and reasonably valuating ecosystem services can provide a scientific basis for the rational development of wetland resources. A series of valuation techniques, such as replacement cost method, contingent valuation method, and travel cost method and so on, have been used extensively to evaluate the value of wetland ecosystem services. Although the number of applications for such techniques to wetland ecosystem services is rapidly growing, site specific estimates are often unavailable. Reasons include time and budget constraints as well as technical challenges of conducting research in areas where wetlands are located. Value transfer techniques are an attractive option for policy-maker facing time and budget constraints when reliable primary valuations are absent. Value transfer makes use of results from previous empirical valuation studies (often termed study sites) and applies their value estimations to the policy site in question. In order to reduce the error inherent in value transfer, meta-analysis is commonly used to provide a more thorough and statistically valid value estimation to use in value transfer. There appear a few published studies on value transfer of ecosystem services in China. This paper presents an empirical study of the meta-analytical value transfer performed to evaluate economic values of China's lakes and marshes ecosystem services. The meta-analysis relied on a database consisting of 281 values estimated from 52 empirical valuation studies on ecosystem services of China’ s lakes and marshes. In this paper, we divided the wetland ecosystem services into 8 categories on the basis of literature review, including aquatic production, raw materials production, recreation and tourism service, water conservation service, flood mitigation service, water purification service, carbon fixation service and oxygen release service. Our findings indicated that both flood mitigation service and water conservation service were the most highly valued wetland services in our sample, and water purification service had the lowest economic value. The meta-regression results revealed a number of important factors in explaining variation in value estimation of ecosystem services, notably the area of lakes and marshes, the number of beneficiaries around the wetland, the differences in economic values among ecosystem services and the differences in valuation methods. We also assessed the robustness of the meta-regression analysis model for out-of-sample value transfer by an n-1 data splitting technique. The transfer errors were from 0.09% to 234.61% and the average transfer error was 19.99%, which is within the acceptable error range of natural resources value transfer. It indicated that value transfer with meta-analysis would be a potentially effective tool for wetland ecosystem services valuation in China. © 2015, Ecological Society of China. All rights reserved.
Liu Y.,Capital Normal University |
Liu Y.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
Zhang J.,Capital Normal University |
Zhang J.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
And 6 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012
Over the last several decades, researchers have studied the hydrological disciplines through observed data. But with the impacts of human activities, the observed data cannot show the real hydrological situation gradually. The quantificational analysis of hydrological response to human activities has become the indispensable foundation when reservoir, water control project and large scale farmland were built. This analysis is facing many unresolved problems, and it becomes the advance front of the field of hydrology and water resource. The effects of human activities on hydrology can be divided into direct effects and indirect effects. The direct effects are classified to irrigate farmland and forests, to build reservoirs and to carry out water control projects and so on. These activities change the quality, quantity and distribution of water resource directly. The indirect effects are urbanization, tree planting and agriculture and so on. These activities influence the water resource indirectly by changing the land use types and weather. In this study, the year of 1986-1987 and 2005-2006 were chosen as two study periods. Two land use maps on the base of two TM images of 1987 and 2005 were classified manually. A SWAT model was setup and carried out in Guishui River basin, Beijing China to simulate the hydrological response to human activities. The results indicated that, human activities had remarkable effects on the runoff. In the study periods, the direct effects influenced the runoff much more than the indirect effects did. The indirect effects increased the runoff, especially dramatically in flood season (June to August) with the variation percentage was 34. 67%. The swelling stage (April to August) and falling stage (September to December) got faster and the runoff showed high relativity to the precipitation. Along with the increase of the precipitation, the relativity was also enhancing, and the upward non-uniform coefficient indicated that the runoff varied more. The direct effects decreased the runoff coefficient by 87%, and more obvious in flood season when the peak values almost disappeared. The decreased non - uniform coefficient indicated that the runoff became well-distributed. So the indirect effects brought more droughts and floods while the direct effects can improve the water operating factor and make fewer droughts and floods. In this paper,conclusions are: (1) In this study, SWAT model simulated the runoff of Guishui River basin reasonable. This study also enriched the experience of the applications of SWAT model in China. (2) The expansion of the urban occupied more and more farmland, and then the farmland encroached on forests and grass. The increasing impervious surface changed the ability of water conservation of Guishui River basin. (3) The direct effects and indirect effects had different mechanism, and the direct effects play the most important role in the changes of the runoff. Hence need to note that the direct effects should be never ignored or be confused with the indirect effects. And more exploration need to do to increase the depth of it. Only in this way can we better understand the hydrological response to human activities clearly and correctly.
Wang S.,Capital Normal University |
Wang S.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
Yu J.,Capital Normal University |
Yu J.,Beijing Key Laboratory of Resource Environment and Geographic Information System |
And 8 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015
Phase unwrapping is a key step in InSAR (Synthetic Aperture Radar Interferometry) processing, and its result may directly affect the accuracy of DEM (Digital Elevation Model) and ground deformation. However, the decoherence phenomenon such as shadows and layover, in the area of severe land subsidence where the terrain is steep and the slope changes greatly, will cause error transmission in the differential wrapped phase information, leading to inaccurate unwrapping phase. In order to eliminate the effect of the noise and reduce the effect of less sampling which caused by topographical factors, a weighted least-squares method based on confidence level in frequency domain is used in this study. This method considered to express the terrain slope in the interferogram as the partial phase frequency in range and azimuth direction, then integrated them into the confidence level. The parameter was used as the constraints of the nonlinear least squares phase unwrapping algorithm, to smooth the un-requirements unwrapped phase gradient and improve the accuracy of phase unwrapping. Finally, comparing with interferometric data of the Beijing subsidence area obtained from TerraSAR verifies that the algorithm has higher accuracy and stability than the normal weighted least-square phase unwrapping algorithms, and could consider to terrain factors. © 2015 SPIE.