Chinese Urban Land Spatial Pattern,Evolution And Its Potential

As the largest developing country in the world,China entered a new stage of development owing to the reform and opening-up policy in 1978 and has accelerated completely since the end of 1980 s.Large population migrated from rural areas to cities,leading to the rapid growth of urban lands,especially some special cities whose area even increased dozens or hundreds of times.Given the vast difference of policies,economy,population,and resources,urban development throughout China suffered from a serious imbalance that need to be solved emergently.Hence,accurate and object monitoring and analysis on urban land distribution and spatial pattern is of great significance on evaluation of urban land internal potential and develop trend,and can provide scientific references for the reasonable and sustainable development of China.Based on the urban land data obtained from the National Land Use/Cover Database of China(NLUD-C),terrain and topography data,population and economy statistical data and ecological landscape metrics,index system of urban land spatial pattern was built up,and it contains 12 metrics.Research subject is urban land and research period is between the late 1980 s and 2010.This study mainly accomplished four tasks as following: 1)in accordance with the empirical model and statistical method,the rationality of urban land and population distribution was evaluated;2)the spatio-temporal characteristics and evolutions of corresponding indicators of Chinese urban land were described;3)urban land ‘spatial pattern' was defined,then the spatial pattern characteristics and evolution of urban land in China was depicted and summarized.4)The population carrying potential,driving force of policies and strategies and its impact on spatial pattern of urban land in China were calculated and predicted.Result shows that: 1)Urban land distribution keeps dense in the eastern and sparse in the western with a decrease from the coastal area to inland area between the ends of 1980 s and 2010.The densest urban lands mainly locate in the Pearl River Delta,Yangtze River Delta and Beijing-Tianjin-Hebei region.Urban land expansion processes successively experienced four different stages: a fast expansion period with an increase rate of 46.52%(1980s-1995),a slow expansion period with an increase rate of 10.74%(1995-2000)and two accelerating expansion periods with the increase rate of 28.20%(2000-2005)and 38.39%(2005-2010).The characteristic of urban population distribution is the similar with urban land,which centralizes in mega cities(the first-tier cities)and extremely sparser in medium and small cities.Obvious differences existed in different size cities,leading to the lack of transition.2)The terrain and topography of urban land in China showed slight changes from 1980 s to 2010.In comparison,the sharper dynamics occurred in the complex topographic areas in the western region,including Qinghai,Sichuan,Tibet,Xinjiang,Inner Mongolia,Yunnan,Guizhou,Ningxia,Gansu and Shaanxi.The terrain and topography of urban land in the central and eastern regions were relatively smooth and hadn't changed a lot.Population and economy exhibited obvious dynamics with the significant increase of urbanization rate,tertiary industry density and tertiary industry proportion as well as the fluctuation of population density.Urban land in and around Guizhou,Sihuan,Chongqing and Shaanxi showed higher population density and lower urbanization rate,whilst that urban land in municipalities and coastal provinces like Beijing,Tianjin,Shanghai,Jiangsu,Zhejiang,Fujian and Guangdong possessed higher urbanization rate and tertiary industry density.Urban land with the more broken and more complete landscapes showed a decrease trend;however,others(neither extremely complex nor extremely simple)increased continuously.Dispersion degree and fractal dimension of urban land in Jiangsu,Zhejiang,Fujian,Jiangxi,Hunan and Hubei was significantly higher than other provinces with broken landscape patches and irregular boundaries.Meanwhile,area weighted plaques average distance of urban land in Tibet,Xinjiang,Qinghai,Inner Mongolia and Sichuan was relatively high with scattered landscape patches.3)This study provides a new definition of urban land ‘spatial pattern' and formulates the standards of spatial pattern description.The spatial pattern includes two aspects: one is the characteristics of distribution and agglomeration of urban land,and the other is the metrics changes of the urban land.There were 7,8,11 and 19 areas,which mainly located between the geographic regions(i.e.,the southwestern and northwestern regions)and the economic regions(i.e.,the central and eastern regions),showed dynamics of distribution and agglomeration during the periods of 1980s-1995,1995-2000,2000-2005 and 2005-2010,respectively.Urban land that showed stable distribution and agglomeration mainly distributed in Tibet,Qinghai,Xinjiang,Yunnan and Inner Mongolia.Terrain and topography complexity,landscape fragmentation and population and economy density were applied to analysis on urban land spatial pattern characteristics after the principal component analysis(PCA).Terrain and topography of urban land in Tibet,Qinghai,Yunnan,Guizhou,Sichuan and Gansu was the most complex,which was followed by the central and northeastern regions,and then the coastal areas.Compared with terrain and topography,the fragmentation of landscape changed more frequently.The landscape fragmentation of Hunan,Hubei,Jiangxi,Fujian,Zhejiang,Jiangsu and Shandong keeps the highest,and Tibet,Qinghai and Gansu keeps the lowest.Population and economy density of urban land is higher in the southwest region and is lower in in Tibet,Qinghai,Xinjiang and Inner Mongolia.In addition,coastal area in the south of the Yangtze River has relatively denser population and economy than the north.4)More than half cities in China with per capita urban construction land(CUCL)larger than 105 m2,population density is lower.According to ‘Urban Land Classification and Planning Construction Land Standard',these urban lands mentioned above possess population carrying potential and mainly distributed in the west and northeast regions such as Xinjiang,Qinghai,Tibet,Inner Mongolia,Jilin and Heilongjiang,and coastal areas such as Jiangsu,Shandong,Tianjin,Hebei Beijing and the Pearl River Delta.The former showed small population carrying potential because of its tiny base of urban land,and the latter was on the contrast.One third of cities in China with CUCL less than 75 m2,and possess no population carrying potential,which mainly distributed in the southwestern region and central provinces such as Jiangxi,Fujian,Hunan and Hubei.Influenced by the politics,strategies and planning,urban land increased much faster in the eastern region than other regions.Meanwhile,metrics of urban land would also show obvious dynamics due to the influences of politics,strategies and planning.However,the dynamic of distribution and agglomeration of urban land is relatively difficult to achieve,it needs a long time to accomplish.