The Research On Coupling Development Relationship Between Urbanization And Environment In Ya'an

The study indicates the indicators about evaluation of coupling relationship between urbanization and environment, meanwhile, the corresponding standard value of each indicator is constructed based on national standard and actuality value of domestic cities that have preferable features and actual conditions of Ya'an. Factor analysis method and coordinated index model are applied in the coupling evaluation. Furthermore, the coordinated index of urbanization and environment is quantitative forecasted dynamically by constructed GM(1,1). Based on above results, different metrology models about the relationship between urbanization rate and environment Index, coordinated index, coordinated development index are built separately to quantitatively analyze the coupling relationship between urbanization and environment and show the coupling development degree between urbanization and environment in Ya'an and the change principle of environment quality with urbanization development.(1) The results of coupling evaluation show that: Yucheng district is in the moderate development stage, but urbanization development lags behind environment development, moreover, other 7 counties of Ya'an is in the primary development stage. Mingshan county is environment lag model in primary development stage, Tianquan county and Lushan county are coordinated model in the same stage and indicate that urbanization component and environment component coordinated develop in low level, Yingjing county, Hanyuan county, Shimian county and Baoxing county are urbanization lag model in the same stage. Basically Ya'an is the transition stage, which it is transiting from urbanization and environment coadjust to both primarily coordinate in 1997-2002, meanwhile, separately show urbanization and environment deficient coordination development urbanization lag model and both primary development urbanization lag model. Though the couplingcoordinated index continually improve year after year, synthetic development level is lower. In the interior relation of urbanization and environment systems, environment quality is correspondingly advanced, while, urbanization development is correspondingly lag.(2) The results of forecast show that: since 2002, urbanization of Ya'an has been developing continually, but it will be still in primary development stage till 2008 and not achieve the first turning point of S-shape curve. Environment Index of Ya'an decline from 2002 to 2008 and, in a certain extent, show change fluctuation. At time scale the coupling coordinated index change along parabola dynamically and will climb to the peak of parabola around 2006, in another word, it will attain optimal coordinated state which urbanization and environment develop in phase. However, coordinated index will decline subsequently and environment quality will lag behind urbanization development. Based on the coordinated development index, coupling development is always in primary development stage and the transition stage which it is transiting from primary development to moderate development. Though holistic benefit of urbanization and environment coordinated development slowly increase from 2002 to 2008, as a whole the coordinated development level is still in lower grade.(3) The results of quantitative analysis show that: it is obvious that there is a quadratic U-shape curve character in the relationship between the urbanization rate and environment quality in Ya'an. The simulated calculation illustrate when urbanization rate reaches 22.11% around in 2008-2009, the worst environment quality turning point of conic would be appear. An obvious invert U-shape curve character will be found, which is similar to EKC between the urbanization rate and coordinated index. Around in 2005-2006, when urbanization rate reaches 20.74%, the theoretical peak value of curve will arrive and the turning point will appear prior than the worst environment quality value. The relationship between the coordinated development index and urbanization rate doesn't show invert U-shape curve but nonstandard cubic curve character. When urbanization rate is 22.03% in 2009, the theoretical peak value of curve will arrive. At that time, the urbanization and environment coupling development will have been transited to moderate coordinated development stage completely and the holistic function of urbanization and environmentsynthetic development reach moderate development level.