In order to study the restoration of road landscape space,subjective evaluation method was adopted to visually evaluate different road spaces in Tianjin University with college students as the research objects.Using r...In order to study the restoration of road landscape space,subjective evaluation method was adopted to visually evaluate different road spaces in Tianjin University with college students as the research objects.Using random block design,9 plots were quantitatively studied by Perceived Restorativeness Scale(PRS)from four dimensions:alienation,compatibility,richness and attractiveness.The results show that gray space has the worst restorative effect in the dimension of alienation,and can not bring people the feeling of being away from daily trivialities;in terms of compatibility dimension,green and blue spaces have better restorative effects;richness dimension has no obvious influence on the restoration of plots;in terms of attraction dimension,blue space has strong restorative ability and can easily attract people’s attention,while gray space has low attraction.There are differences in environmental restoration among different types of road space,and gray space,blue space and green space show weak,strong,and relatively stable restorative effects,respectively.展开更多
In this study, regional persistent haze events(RPHEs) in the Beijing–Tianjin–Hebei(BTH) region were identified based on the Objective Identification Technique for Regional Extreme Events for the period 1980–2013. T...In this study, regional persistent haze events(RPHEs) in the Beijing–Tianjin–Hebei(BTH) region were identified based on the Objective Identification Technique for Regional Extreme Events for the period 1980–2013. The formation mechanisms of the severe RPHEs were investigated with focus on the atmospheric circulation and dynamic mechanisms. Results indicated that:(1) 49 RPHEs occurred during the past 34 years.(2) The severe RPHEs could be categorized into two types according to the large-scale circulation, i.e. the zonal westerly airflow(ZWA) type and the high-pressure ridge(HPR) type. When the ZWA-type RPHEs occurred, the BTH region was controlled by near zonal westerly airflow in the mid–upper troposphere.Southwesterly winds prevailed in the lower troposphere, and near-surface wind speeds were only 1–2 ms^(-1). Warm and humid air originating from the northwestern Pacific was transported into the region, where the relative humidity was 70% to 80%, creating favorable moisture conditions. When the HPR-type RPHEs appeared, northwesterly airflow in the mid–upper troposphere controlled the region. Westerly winds prevailed in the lower troposphere and the moisture conditions were relatively weak.(3) Descending motion in the mid-lower troposphere caused by the above two circulation types provided a crucial dynamic mechanism for the formation of the two types of RPHEs. The descending motion contributed to a reduction in the height of the planetary boundary layer(PBL), which generated an inversion in the lower troposphere. This inversion trapped the abundant pollution and moisture in the lower PBL, leading to high concentrations of pollutants.展开更多
Molar-tooth(MT) structure is an enigmatic sedimentary structure consisting of variously-shaped cracks and voids filled with a characteristically uniform,equant calcite microspar.It is globally distributed but temporal...Molar-tooth(MT) structure is an enigmatic sedimentary structure consisting of variously-shaped cracks and voids filled with a characteristically uniform,equant calcite microspar.It is globally distributed but temporally restricted to rocks from Neoarchean to Neoproterozoic age.The origin of MT structures has been debated for more than a century and the topic continues to be highly contentious.Some features of MT structure occurring in micritic limestones of the Mesoproterozoic Gaoyuzhuang Formation(ca.15...展开更多
On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consi...On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C. revularis. From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age). The top has different reliefs . Although there is an effect of spatial shift of estuary position, the top is only distributed in the range of-0. 50--2. 50 m(Huanghai elevation minus National elevation system). The banks cannot explain the sea-level fluctuation. As the string ostracean banks are distributed near E-W direction, it suggests that the direction of tidal currents was then similar to that of the present day.展开更多
Tianjin is one of the inland cities with the most severe cases of subsidence hazard in China.The majority of the existing studies have mainly focused on Beijing-Tianjin-Hebei,and little attention has been given to Tia...Tianjin is one of the inland cities with the most severe cases of subsidence hazard in China.The majority of the existing studies have mainly focused on Beijing-Tianjin-Hebei,and little attention has been given to Tianjin.In addition,these existing studies are short-term investigations,lacking long-term monitoring of surface subsidence.In the present study,we use the Small Baseline Subset Interferometric Synthetic Aperture Radar(SBAS-InSAR)technique to monitor the subsidence process in Tianjin between 2015 and 2020 and reveal its spatial and temporal variation.We divided the 44-view Sentinel-1A image data into three periods to avoid the effect of temporal and spatial decoherence by extracting the surface deformation field in Tianjin.We finally verified the accuracy and reliability of the inversion results using second-order leveling data.Results showed that the correlation coefficient r between the two reached 0.89,and the root mean square error was 4.84 mm/y.Obvious subsidence funnels exist in Tianjin,mainly in the towns of Wangqingtuo and Shengfang.These subsidence funnels have a subsidence deformation rate of-136.2 mm/y and a maximum cumulative settlement of-346.3 mm within the study period.The subsidence area tends to extend to the southwest.The analysis of annual rainfall,groundwater resource extraction,spatial location distribution of industrial areas combined with SBAS-InSAR inversion results indicates that overextraction of groundwater resources is the main cause of land subsidence in the area.Therefore,strict control of groundwater extraction is the main approach to mitigate land subsidence effectively.展开更多
Taking Tianjin as an example,this paper proposed a methodology and process for evaluating near-fault strong ground motions from future earthquakes to mitigate earthquake damage for the metropolitan area and important ...Taking Tianjin as an example,this paper proposed a methodology and process for evaluating near-fault strong ground motions from future earthquakes to mitigate earthquake damage for the metropolitan area and important engineering structures.The result of strong ground motion was predicted for Tianjin main faults by the hybrid method which mainly consists of 3D finite difference method and stochastic Green's function.Simulation is performed for 3D structures of Tianjin region and characterized asperity models.The characterized asperity model describing source heterogeneity is introduced following the fault information from the project of Tianjin Active Faults and Seismic Hazard Assessment.We simulated the worst case that two earthquakes separately occur.The results indicate that the fault position,rupture process and the sedimentary deposits of the basin significantly affect amplification of the simulated ground motion.Our results also demonstrate the possibility of practical simulating wave propagation including basin induced surface waves in broad frequency-band,for seismic hazard analysis near the fault from future earthquakes in urbanized areas.展开更多
Since its establishment about ten years ago, TEDA has taken advantage of eachopportune time created by China’s policy of opening wider and wider to the outsideworld and the rapid economic growth to deepen its reform ...Since its establishment about ten years ago, TEDA has taken advantage of eachopportune time created by China’s policy of opening wider and wider to the outsideworld and the rapid economic growth to deepen its reform and extend its exploitation,and thus has maintained a favorable momentum and an extraordinary high speed foreconomic development. With the total economic output of the whole area raised to展开更多
In order to analyze the factors influencing carbon emissions in the region of Beijing-Tianjin-Hebei and to explore the pathways to developing a low-carbon economy,this paper begins with the terminal energy consumption...In order to analyze the factors influencing carbon emissions in the region of Beijing-Tianjin-Hebei and to explore the pathways to developing a low-carbon economy,this paper begins with the terminal energy consumption of three industries and residential consumption,and constructs an identical equation which is composed of population size,level of economic development,energy intensity,the proportion of energy consumption,energy structure,and the coefficient of carbon emissions.Based on the data of terminal energy consumption during 2000-2012,various factors are analyzed and their contribution is measured by Logarithmic Mean Divisia Index(LMDI).The results show that the levels of population and economy have a positive driving effect while energy intensity,energy structure,and carbon intensity have a negative driving effect;the proportion of energy consumption had a negative driving effect prior to 2006,then changed to positive.Among suggestions for a low-carbon economy are controlling population size,improving the quality of economic development,supporting research into new energy technology,accelerating regional integration and optimizing industrial structure,and enhancing environmental protection and spreading the concept of a low-carbon economy.展开更多
As the space carrier of the construction of ecological civilization, land's green and efficient utilization is an important guarantee for realizing national sustainable development. Based on traditional land evalu...As the space carrier of the construction of ecological civilization, land's green and efficient utilization is an important guarantee for realizing national sustainable development. Based on traditional land evaluation, this paper scientifically defines the green land use, puts land as one of the production factors, and brings energy consumption, environmental pollution, etc. into the input-output system to measure the green land utilization efficiency of the urban construction land of Beijing-TianjinHebei Urban Agglomeration from 2006 to 2016. The study shows that the overall efficiency variation of the urban agglomeration is related with the land and environment policies. Efficiency of 2016 is higher than that of 2006, and energy and environment are the principal factors affecting the green land use. The efficiency of each city is positively correlated with its economic development, negatively correlated with the construction land expansion. Efficiency gaps in different cities are expanding.There is positive correlation with overall weak space between cities, and the partial spatial agglomeration phenomenon appears. Therefore, the green land use efficiency could be improved by improving land utilization efficiency, coordinating economic growth of construction land utilization with environmental protection and taking feasible ways to transregional renovation of the stock ecological land utilization, etc.展开更多
The course of rural human settlement environment governance in Tianjin could be roughly divided into four stages:germination,initiation,promotion and deepening.After the development for nearly 20 years,rural human set...The course of rural human settlement environment governance in Tianjin could be roughly divided into four stages:germination,initiation,promotion and deepening.After the development for nearly 20 years,rural human settlement environment governance of Tianjin is faced with many difficulties,such as imperfect village construction planning,poor use effect of sewage facilities,low participation of farmers,and insufficient financial investment.Therefore,some countermeasures and suggestions are put forward,such as scientific planning and overall consideration,innovating financing mechanism,encouraging diversified investment of funds,and strengthening the publicity of rural human settlement environment governance.展开更多
Launched in 2002, the Beiing–Tianjin Sand Source Control Project (BTSSCP) is an ecological restoration project intended to prevent desertification in China. Evidence from multiple sources has confirmed increases in v...Launched in 2002, the Beiing–Tianjin Sand Source Control Project (BTSSCP) is an ecological restoration project intended to prevent desertification in China. Evidence from multiple sources has confirmed increases in vegetation growth in the BTSSCP region since the initiation of this project. Precipitation and essential climate variable-soil moisture (ECV-SM) conditions are typically considered to be the main drivers of vegetation growth in this region. Although many studies have investigated the inter-annual variations of vegetation growth, few concerns have been focused on the annual and seasonal variations of vegetation growth and their climatic drivers, which are crucial for understanding the relationships among the climate, vegetation, and human activities at the regional scale. Based on the normalized difference vegetation index (NDVI) derived from MODIS and the corresponding climatic data, we explored the responses of vegetation growth to climatic factors at annual and seasonal scales in the BTSSCP region during the period 2000–2014. Over the study region as a whole, NDVI generally increased from 2000 to 2014, at a rate of 0.002/a. Vegetation growth is stimulated mainly by the elevated temperature in spring, whereas precipitation is the leading driver of summer greening. In autumn, positive effects of both temperature and precipitation on vegetation growth were observed. The warming in spring promotes vegetation growth but reduces ECV-SM. Summer greening has a strong cooling effect on land surface temperature. These results indicate that the ecological and environmental consequences of ecological restoration projects should be comprehensively evaluated.展开更多
Using a heterogeneity stochastic frontier model(HSFM),we empirically investigated the economic efficiency of Beijing-Tianjin-Hebei from 2003 to 2016 and its influencing factors.The key findings of the paper lie in:1)i...Using a heterogeneity stochastic frontier model(HSFM),we empirically investigated the economic efficiency of Beijing-Tianjin-Hebei from 2003 to 2016 and its influencing factors.The key findings of the paper lie in:1)in Beijing-Tianjin-Hebei,the overall economic and technological efficiency tended to increase in a wavelike manner,economic growth slowed down,and there was an obvious imbalance in economic efficiency between the different districts,counties and cities;2)the heterogeneity stochastic frontier production functions(SFPFs)of Beijing,Tianjin and Hebei were different from each other,and investment was still an important impetus of economic growth in Beijing-Tianjin-Hebei;3)economic efficiency was positively correlated with economic agglomeration,human capital,industrial structure,infrastructure,the informatization level,and institutional factors,but negatively correlated with the government role and economic opening.The following policy suggestions are offered:1)to improve regional economic efficiency and reduce the economic gap in Beijing-Tianjin-Hebei,governments must reduce their intervention in economic activities,stimulate the potentials of labor and capital,optimize the structure of human resources,and foster new demographic incentives;2)governments must guide economic factors that are reasonable throughout Beijing-Tianjin-Hebei and strengthen infrastructure construction in underdeveloped regions,thus attaining sustainable economic development;3)governments must plan overall economic growth factors of Beijing-Tianjin-Hebei and promote reasonable economic factors(e.g.,labor,resources,and innovations)across different regions,thus attaining complementary advantages between Beijing,Tianjin,and Hebei.展开更多
With the industrial competitiveness in the Beijing-Tianjin-Hebei area in 2013 as the object of study,this paper uses principal component analysis to evaluate and compare the industrial competitiveness in the Beijing-T...With the industrial competitiveness in the Beijing-Tianjin-Hebei area in 2013 as the object of study,this paper uses principal component analysis to evaluate and compare the industrial competitiveness in the Beijing-Tianjin-Hebei area,in order to provide reference for Beijing-Tianjin-Hebei joint development. The results show that in terms of industrial structure competitiveness,Beijing > Tianjin > Hebei; in terms of agricultural competitiveness,Tianjin > Beijing > Hebei; in terms of industrial competitiveness,Tianjin > Beijing > Hebei; in terms of service industry competitiveness,Tianjin > Beijing > Hebei; in terms of high-tech industry competitiveness,Beijing > Tianjin > Hebei. It is suggested that Beijing-Tianjin-Hebei should further optimize industrial structure,and develop modern service industry. In the Beijing-TianjinHebei joint development,Hebei should focus on the development of agriculture,Tianjin should focus on the development of industry,and Beijing should focus on the development of high-tech industry.展开更多
基金Special Research Program of Tianjin Municipal Education Commission(Psychological Health Education)(2020ZXXL-GX03G)2022 School-level Cultivation Project of Hetian Polytechnic(HZ202310).
文摘In order to study the restoration of road landscape space,subjective evaluation method was adopted to visually evaluate different road spaces in Tianjin University with college students as the research objects.Using random block design,9 plots were quantitatively studied by Perceived Restorativeness Scale(PRS)from four dimensions:alienation,compatibility,richness and attractiveness.The results show that gray space has the worst restorative effect in the dimension of alienation,and can not bring people the feeling of being away from daily trivialities;in terms of compatibility dimension,green and blue spaces have better restorative effects;richness dimension has no obvious influence on the restoration of plots;in terms of attraction dimension,blue space has strong restorative ability and can easily attract people’s attention,while gray space has low attraction.There are differences in environmental restoration among different types of road space,and gray space,blue space and green space show weak,strong,and relatively stable restorative effects,respectively.
基金jointly sponsored by the National Basic Research Program of China(973 Program)(Grant No.2013CB430202)the National Natural Science Foundation of China(Grant No.41401056)+1 种基金the China Meteorological Administration Special Public Welfare Research Fund(Grant No.GYHY201406001)the Research Innovation Program for College Graduates of Jiangsu Province(Grant No.KYLX15 0858)
文摘In this study, regional persistent haze events(RPHEs) in the Beijing–Tianjin–Hebei(BTH) region were identified based on the Objective Identification Technique for Regional Extreme Events for the period 1980–2013. The formation mechanisms of the severe RPHEs were investigated with focus on the atmospheric circulation and dynamic mechanisms. Results indicated that:(1) 49 RPHEs occurred during the past 34 years.(2) The severe RPHEs could be categorized into two types according to the large-scale circulation, i.e. the zonal westerly airflow(ZWA) type and the high-pressure ridge(HPR) type. When the ZWA-type RPHEs occurred, the BTH region was controlled by near zonal westerly airflow in the mid–upper troposphere.Southwesterly winds prevailed in the lower troposphere, and near-surface wind speeds were only 1–2 ms^(-1). Warm and humid air originating from the northwestern Pacific was transported into the region, where the relative humidity was 70% to 80%, creating favorable moisture conditions. When the HPR-type RPHEs appeared, northwesterly airflow in the mid–upper troposphere controlled the region. Westerly winds prevailed in the lower troposphere and the moisture conditions were relatively weak.(3) Descending motion in the mid-lower troposphere caused by the above two circulation types provided a crucial dynamic mechanism for the formation of the two types of RPHEs. The descending motion contributed to a reduction in the height of the planetary boundary layer(PBL), which generated an inversion in the lower troposphere. This inversion trapped the abundant pollution and moisture in the lower PBL, leading to high concentrations of pollutants.
基金the project"A Study of the Cycles and Events for the Mesoproterozoic Jixian System in the Yan Mountain Region,northern China"(Nos.49802012, 40472065)financially supported by the National Foundation of Natural Sciences of China
文摘Molar-tooth(MT) structure is an enigmatic sedimentary structure consisting of variously-shaped cracks and voids filled with a characteristically uniform,equant calcite microspar.It is globally distributed but temporally restricted to rocks from Neoarchean to Neoproterozoic age.The origin of MT structures has been debated for more than a century and the topic continues to be highly contentious.Some features of MT structure occurring in micritic limestones of the Mesoproterozoic Gaoyuzhuang Formation(ca.15...
基金The subject was funded by Xi'an Laboratory of Loess and Quaternary Geology, Academia Sinica
文摘On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C. revularis. From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age). The top has different reliefs . Although there is an effect of spatial shift of estuary position, the top is only distributed in the range of-0. 50--2. 50 m(Huanghai elevation minus National elevation system). The banks cannot explain the sea-level fluctuation. As the string ostracean banks are distributed near E-W direction, it suggests that the direction of tidal currents was then similar to that of the present day.
基金Natural Science Foundation of Guangxi(Nos.2018GXNSFBA050006,2020GXNSFBA159033)Wuhan Science and Technology Plan Project(No.2019010702011314)+2 种基金Guangxi Science and Technology Plan Project(No.GUIKE AD19110107)National Natural Science Foundation of China(Nos.42064003,42064002)Guangxi Universities Young and Middle-aged Teachers’Basic Scientific Research Ability Improvement Project(No.2020KY0603)。
文摘Tianjin is one of the inland cities with the most severe cases of subsidence hazard in China.The majority of the existing studies have mainly focused on Beijing-Tianjin-Hebei,and little attention has been given to Tianjin.In addition,these existing studies are short-term investigations,lacking long-term monitoring of surface subsidence.In the present study,we use the Small Baseline Subset Interferometric Synthetic Aperture Radar(SBAS-InSAR)technique to monitor the subsidence process in Tianjin between 2015 and 2020 and reveal its spatial and temporal variation.We divided the 44-view Sentinel-1A image data into three periods to avoid the effect of temporal and spatial decoherence by extracting the surface deformation field in Tianjin.We finally verified the accuracy and reliability of the inversion results using second-order leveling data.Results showed that the correlation coefficient r between the two reached 0.89,and the root mean square error was 4.84 mm/y.Obvious subsidence funnels exist in Tianjin,mainly in the towns of Wangqingtuo and Shengfang.These subsidence funnels have a subsidence deformation rate of-136.2 mm/y and a maximum cumulative settlement of-346.3 mm within the study period.The subsidence area tends to extend to the southwest.The analysis of annual rainfall,groundwater resource extraction,spatial location distribution of industrial areas combined with SBAS-InSAR inversion results indicates that overextraction of groundwater resources is the main cause of land subsidence in the area.Therefore,strict control of groundwater extraction is the main approach to mitigate land subsidence effectively.
基金supported by the National Natural Science Foundation of China (40674016)Earthquake Research Fund of Ministry of Science and Technology of China ((2007)203/8-53)
文摘Taking Tianjin as an example,this paper proposed a methodology and process for evaluating near-fault strong ground motions from future earthquakes to mitigate earthquake damage for the metropolitan area and important engineering structures.The result of strong ground motion was predicted for Tianjin main faults by the hybrid method which mainly consists of 3D finite difference method and stochastic Green's function.Simulation is performed for 3D structures of Tianjin region and characterized asperity models.The characterized asperity model describing source heterogeneity is introduced following the fault information from the project of Tianjin Active Faults and Seismic Hazard Assessment.We simulated the worst case that two earthquakes separately occur.The results indicate that the fault position,rupture process and the sedimentary deposits of the basin significantly affect amplification of the simulated ground motion.Our results also demonstrate the possibility of practical simulating wave propagation including basin induced surface waves in broad frequency-band,for seismic hazard analysis near the fault from future earthquakes in urbanized areas.
文摘Since its establishment about ten years ago, TEDA has taken advantage of eachopportune time created by China’s policy of opening wider and wider to the outsideworld and the rapid economic growth to deepen its reform and extend its exploitation,and thus has maintained a favorable momentum and an extraordinary high speed foreconomic development. With the total economic output of the whole area raised to
基金supported by Research on humanistic and social science from the Department of Education[grant number 13YJAZH122]
文摘In order to analyze the factors influencing carbon emissions in the region of Beijing-Tianjin-Hebei and to explore the pathways to developing a low-carbon economy,this paper begins with the terminal energy consumption of three industries and residential consumption,and constructs an identical equation which is composed of population size,level of economic development,energy intensity,the proportion of energy consumption,energy structure,and the coefficient of carbon emissions.Based on the data of terminal energy consumption during 2000-2012,various factors are analyzed and their contribution is measured by Logarithmic Mean Divisia Index(LMDI).The results show that the levels of population and economy have a positive driving effect while energy intensity,energy structure,and carbon intensity have a negative driving effect;the proportion of energy consumption had a negative driving effect prior to 2006,then changed to positive.Among suggestions for a low-carbon economy are controlling population size,improving the quality of economic development,supporting research into new energy technology,accelerating regional integration and optimizing industrial structure,and enhancing environmental protection and spreading the concept of a low-carbon economy.
基金supported by National Social Science Foundation of China"Research on the Spatial Optimization Mechanism and Path of the National Urban New District from the Perspective of Urban Agglomeration Integration"[Grant number:16BGL208],the principal of the project:Xia ZhouNational Natural Science Foundation of China"Coupling Mechanism between Land Price Gradient and Industrial Gradient and Optimization of Industrial Structure of Urban Agglomeration"[Grant number:71173148]Beijing Science and Technology Support"Green Channel"Project"Land Security for Non-capital Core Functions"[Grant number:2161100001116016],the principal of the project:Deqi Wang
文摘As the space carrier of the construction of ecological civilization, land's green and efficient utilization is an important guarantee for realizing national sustainable development. Based on traditional land evaluation, this paper scientifically defines the green land use, puts land as one of the production factors, and brings energy consumption, environmental pollution, etc. into the input-output system to measure the green land utilization efficiency of the urban construction land of Beijing-TianjinHebei Urban Agglomeration from 2006 to 2016. The study shows that the overall efficiency variation of the urban agglomeration is related with the land and environment policies. Efficiency of 2016 is higher than that of 2006, and energy and environment are the principal factors affecting the green land use. The efficiency of each city is positively correlated with its economic development, negatively correlated with the construction land expansion. Efficiency gaps in different cities are expanding.There is positive correlation with overall weak space between cities, and the partial spatial agglomeration phenomenon appears. Therefore, the green land use efficiency could be improved by improving land utilization efficiency, coordinating economic growth of construction land utilization with environmental protection and taking feasible ways to transregional renovation of the stock ecological land utilization, etc.
基金Supported by 2019 University Students in Tianjin Innovation Training Program Project"Investigation and Research on Rural Living Environment in Xiqing District"(201910061080)
文摘The course of rural human settlement environment governance in Tianjin could be roughly divided into four stages:germination,initiation,promotion and deepening.After the development for nearly 20 years,rural human settlement environment governance of Tianjin is faced with many difficulties,such as imperfect village construction planning,poor use effect of sewage facilities,low participation of farmers,and insufficient financial investment.Therefore,some countermeasures and suggestions are put forward,such as scientific planning and overall consideration,innovating financing mechanism,encouraging diversified investment of funds,and strengthening the publicity of rural human settlement environment governance.
基金financially supported by the National Natural Science Foundation of China (31560135, 41361100)the Discipline Construction Fund Project of Gansu Agricultural University (GAU-XKJS-2018-104, GAU-XKJS-2018-108)the Gansu Science and Technology Support Program (1604FKCA088)
文摘Launched in 2002, the Beiing–Tianjin Sand Source Control Project (BTSSCP) is an ecological restoration project intended to prevent desertification in China. Evidence from multiple sources has confirmed increases in vegetation growth in the BTSSCP region since the initiation of this project. Precipitation and essential climate variable-soil moisture (ECV-SM) conditions are typically considered to be the main drivers of vegetation growth in this region. Although many studies have investigated the inter-annual variations of vegetation growth, few concerns have been focused on the annual and seasonal variations of vegetation growth and their climatic drivers, which are crucial for understanding the relationships among the climate, vegetation, and human activities at the regional scale. Based on the normalized difference vegetation index (NDVI) derived from MODIS and the corresponding climatic data, we explored the responses of vegetation growth to climatic factors at annual and seasonal scales in the BTSSCP region during the period 2000–2014. Over the study region as a whole, NDVI generally increased from 2000 to 2014, at a rate of 0.002/a. Vegetation growth is stimulated mainly by the elevated temperature in spring, whereas precipitation is the leading driver of summer greening. In autumn, positive effects of both temperature and precipitation on vegetation growth were observed. The warming in spring promotes vegetation growth but reduces ECV-SM. Summer greening has a strong cooling effect on land surface temperature. These results indicate that the ecological and environmental consequences of ecological restoration projects should be comprehensively evaluated.
基金Under the auspices of National Natural Science Foundation of China(No.41771131,41301116,41877523)Premium Funding Project for Academic Human Resources Development in Beijing Union University(No.BPHR2017CS13)
文摘Using a heterogeneity stochastic frontier model(HSFM),we empirically investigated the economic efficiency of Beijing-Tianjin-Hebei from 2003 to 2016 and its influencing factors.The key findings of the paper lie in:1)in Beijing-Tianjin-Hebei,the overall economic and technological efficiency tended to increase in a wavelike manner,economic growth slowed down,and there was an obvious imbalance in economic efficiency between the different districts,counties and cities;2)the heterogeneity stochastic frontier production functions(SFPFs)of Beijing,Tianjin and Hebei were different from each other,and investment was still an important impetus of economic growth in Beijing-Tianjin-Hebei;3)economic efficiency was positively correlated with economic agglomeration,human capital,industrial structure,infrastructure,the informatization level,and institutional factors,but negatively correlated with the government role and economic opening.The following policy suggestions are offered:1)to improve regional economic efficiency and reduce the economic gap in Beijing-Tianjin-Hebei,governments must reduce their intervention in economic activities,stimulate the potentials of labor and capital,optimize the structure of human resources,and foster new demographic incentives;2)governments must guide economic factors that are reasonable throughout Beijing-Tianjin-Hebei and strengthen infrastructure construction in underdeveloped regions,thus attaining sustainable economic development;3)governments must plan overall economic growth factors of Beijing-Tianjin-Hebei and promote reasonable economic factors(e.g.,labor,resources,and innovations)across different regions,thus attaining complementary advantages between Beijing,Tianjin,and Hebei.
文摘With the industrial competitiveness in the Beijing-Tianjin-Hebei area in 2013 as the object of study,this paper uses principal component analysis to evaluate and compare the industrial competitiveness in the Beijing-Tianjin-Hebei area,in order to provide reference for Beijing-Tianjin-Hebei joint development. The results show that in terms of industrial structure competitiveness,Beijing > Tianjin > Hebei; in terms of agricultural competitiveness,Tianjin > Beijing > Hebei; in terms of industrial competitiveness,Tianjin > Beijing > Hebei; in terms of service industry competitiveness,Tianjin > Beijing > Hebei; in terms of high-tech industry competitiveness,Beijing > Tianjin > Hebei. It is suggested that Beijing-Tianjin-Hebei should further optimize industrial structure,and develop modern service industry. In the Beijing-TianjinHebei joint development,Hebei should focus on the development of agriculture,Tianjin should focus on the development of industry,and Beijing should focus on the development of high-tech industry.
