The article presents results inducing pollution of the air which is through traffic automotive vehicles. of research of diesel engines working the exhaust gas smokiness against its in city agglomeration working genera...The article presents results inducing pollution of the air which is through traffic automotive vehicles. of research of diesel engines working the exhaust gas smokiness against its in city agglomeration working general pollution in two urban Also the study of the factors agglomerations with similar展开更多
The scaling laws of human mobility are one of the key theories of human geography.They also have important policy implications for urban-rural integration and regional economic growth.Although scaling laws of human mo...The scaling laws of human mobility are one of the key theories of human geography.They also have important policy implications for urban-rural integration and regional economic growth.Although scaling laws of human mobility have been widely discussed,the allometric growth between urban and rural areas is overlooked.This study aims to fill the gap by investigating scaling laws and power-law distribution across urban and rural areas during urban growth with individual people’s trajectory information of 13 million mobile phone users.The analysis identified a turning point at a population of 1.8 million in the Greater Bay Area,where the growth rate of aggregate travel demand stabilizes.The results show that human mobility exhibits segmented allometric growth,with superlinear growth transitioning to sublinear beyond this turning point.The disparities of travel behaviour patterns between urban and rural populations increase as cities grow.These findings would enhance the existing knowledge of the allometric scaling of human mobility.展开更多
Using the total ozone mapping spectrometer(TOMS)aerosol optical depth(AOD)data and the sunshine duration,fog days,low cloud cover(LCC),etc.meteorological data in 1979-2000 in North China,as well as empirical orthogona...Using the total ozone mapping spectrometer(TOMS)aerosol optical depth(AOD)data and the sunshine duration,fog days,low cloud cover(LCC),etc.meteorological data in 1979-2000 in North China,as well as empirical orthogonal function(EOF)mode statistical analyses method,the winter aerosol distributive character of Beijing and peripheral city agglomeration and its influence effect on regional climate are investigated in this paper,especially the relation between aerosol influence effect and distinct change regions of eigenvectors of EOF mode.It is found from analyzing the regional distribution of the long-term averaged winter TOMS AOD that there is a large-scale relatively stable high value zone of aerosol concentration in the valley of the Beijing and peripheral U-shape megarelief.A high correlation area of AOD between Beijing and its southern peripheral exists in winter,and in this significant region of aerosol interaction,there is'in-phase'character of the interannual variations of winter AOD,fog days,and LCCs.It indicates that the variations of aerosol in Beijing and its peripheral areas have impacts on interannual changes of fog days and LCCs in this area.The EOF analyses of the meteorological data further reveal the climate change regions and long-term trends of winter sunshine duration-reducing,and LCC-and fog days-increasing in North China.The areas of significant changes of the first EOF eigenvectors(FEE)of sunshine duration,fog days,LCCs almost superpose on corresponding marked regions of interdecadal differences between the 1990s and 1980s,and all accord with the S-N zonal high value pattern and high correlation region of winter AOD in Beijing and its peripheral areas.Interannual variations of their associated time coefficients(ATC)are in phase with that of regional mean AOD,and both of them have a secular rising trend.Results by EOF mode analyses depict the regional climatic change principal character of winter sunshine duration-reducing,and LCC-and fog days-increasing in peripheral areas to the south of Beijing,and reveal the regional influence effect of aerosol,i.e.the high value zone of long-term averaged winter AOD,significant change regions of FEE of sunshine duration,fog days,and LCC all lie in peripheral city agglomeration to the south of Beijing.These distributive features above suggest that there exists a regional strengthening trend of aerosol climatic effect within influence domain in peripheral city agglomeration to the south of Beijing.展开更多
文摘The article presents results inducing pollution of the air which is through traffic automotive vehicles. of research of diesel engines working the exhaust gas smokiness against its in city agglomeration working general pollution in two urban Also the study of the factors agglomerations with similar
基金supported by National Natural Science Foundation of China(41925003,42130402)Shenzhen science and technology program(JCYJ20220818100810024,KQTD20221101093604016).
文摘The scaling laws of human mobility are one of the key theories of human geography.They also have important policy implications for urban-rural integration and regional economic growth.Although scaling laws of human mobility have been widely discussed,the allometric growth between urban and rural areas is overlooked.This study aims to fill the gap by investigating scaling laws and power-law distribution across urban and rural areas during urban growth with individual people’s trajectory information of 13 million mobile phone users.The analysis identified a turning point at a population of 1.8 million in the Greater Bay Area,where the growth rate of aggregate travel demand stabilizes.The results show that human mobility exhibits segmented allometric growth,with superlinear growth transitioning to sublinear beyond this turning point.The disparities of travel behaviour patterns between urban and rural populations increase as cities grow.These findings would enhance the existing knowledge of the allometric scaling of human mobility.
基金supported by the Major State Basic Research Development Program("973"Project)(Grant No.TG1999045700)the International Sci-Tech Cooperative Project of the Ministry of Science and Technology of the People's Republic of China(Grant No.2004DFA06100).
文摘Using the total ozone mapping spectrometer(TOMS)aerosol optical depth(AOD)data and the sunshine duration,fog days,low cloud cover(LCC),etc.meteorological data in 1979-2000 in North China,as well as empirical orthogonal function(EOF)mode statistical analyses method,the winter aerosol distributive character of Beijing and peripheral city agglomeration and its influence effect on regional climate are investigated in this paper,especially the relation between aerosol influence effect and distinct change regions of eigenvectors of EOF mode.It is found from analyzing the regional distribution of the long-term averaged winter TOMS AOD that there is a large-scale relatively stable high value zone of aerosol concentration in the valley of the Beijing and peripheral U-shape megarelief.A high correlation area of AOD between Beijing and its southern peripheral exists in winter,and in this significant region of aerosol interaction,there is'in-phase'character of the interannual variations of winter AOD,fog days,and LCCs.It indicates that the variations of aerosol in Beijing and its peripheral areas have impacts on interannual changes of fog days and LCCs in this area.The EOF analyses of the meteorological data further reveal the climate change regions and long-term trends of winter sunshine duration-reducing,and LCC-and fog days-increasing in North China.The areas of significant changes of the first EOF eigenvectors(FEE)of sunshine duration,fog days,LCCs almost superpose on corresponding marked regions of interdecadal differences between the 1990s and 1980s,and all accord with the S-N zonal high value pattern and high correlation region of winter AOD in Beijing and its peripheral areas.Interannual variations of their associated time coefficients(ATC)are in phase with that of regional mean AOD,and both of them have a secular rising trend.Results by EOF mode analyses depict the regional climatic change principal character of winter sunshine duration-reducing,and LCC-and fog days-increasing in peripheral areas to the south of Beijing,and reveal the regional influence effect of aerosol,i.e.the high value zone of long-term averaged winter AOD,significant change regions of FEE of sunshine duration,fog days,and LCC all lie in peripheral city agglomeration to the south of Beijing.These distributive features above suggest that there exists a regional strengthening trend of aerosol climatic effect within influence domain in peripheral city agglomeration to the south of Beijing.
