Study on Spatial Development Patterns and Regulation Tactics of Metropolitan Areas from a Vision of Low Carbon——A Case Study of Xi'an

YU Kan-hua,ZHANG Pei School of Architecture,Xi'an University of Architecture and Technology,Shanxi Xi'an 71 0055

WANG Yan-an School of Architecture,Xi'an University of Architecture and Technology,Shanxi Xi'an 710055 School of Urban Construction,Yangtze University,Hubei Jingzhou 434023

Currently,low-carbon revolution has engulfed the entire world.China's urbanization is also in the critical historical period,it is obvious that the pattern of urban spatial growth should immediately acclimate to the system reformation and mechanism innovation.Against the background of advocating developing ecological civilization and a resource thrift and environment friendly society,low carbon eco-city construction has been the inexorable choice of achieving sustainable development.Regarding metropolitan as the research subject,this study explored sustainable spatial construction polices following the idea of low-carbon,looking forward to provide some useful inspiration for metropolitan spatial development[1,2].

1 Connotation identification:recognition of urban spatial development from the vision of low-carbon

In practice,urban planning hardly exert the function of regulation,accordingly lead to the deterioration of ecological environment,which in turn,impede the expansion of urban space and the optimization of spatial structure,hindering the urbanization process seriously.

1.1 Rational growth and extensive growth

There have always been existing two opposing phenomenon in the expansion of urban space in China's urbanization process.Extensive growth means an unsustainable urban spatial growth way in which the utilization of urban space is inefficient and the structure of urban space is jumbled.Extensive growth is characterized by occupation of farmland and greenbelts,lost of urban culture,redundant development of regional infrastructure,and damage of valuable cultural relics.In this urban spatial extending pattern,high-density space and low-density space are found mixed together irrationally.While rational growth is a new development way that putting forward Chinese characteristics,working out measures to suit local conditions,and reinforcing complementary advantages between urban and rural areas on the premise of mobilizing and utilizing socialist strength.

1.2 Rational growth and low-carbon development

Development and growth are hot topics both in China and in the world.To place too much emphasis on growth or to stress development excessively would lead to imbalance in social development,thus hindering the progress of society.Four types of measures have been taken at home and abroad to lower energy consumption and reduce pollutants discharge[3]:①technological measures,②policy measures,③system measures,④organization measures.According to this paper,in the ecological civilization era during which mode of production,mode of life and values changed dramatically,spatial grow th cannot be simply equaled with a healthy development.The new pattern should involve value reason and implement reason that are integrated and complemented by each other to build eco-city network,achieve compact development,and form low-carbon development patterns.Based on low-carbon development vision,value orientation as follow s should be included:①respect nature-construct a complete urban ecological system;②respect society and individual-build humanized ecological community;③keep functional diversity-maintain stability of ecological system;④save resources-realize the sustainable development of urban ecological system[4].

1.3 Re-cognition

According to the above cognition,we have to change our urban development pattern which is based on fossil fuel to low-carbon economy and ecological civilization to face the global warming challenge[4].Specifically,we need to pursue a low-carbon urban development pattern characterized by low amount of emission and high energy-efficient,which requires transformation in development values and methodology.According to this paper,urban spatial development from the low-carbon vision is a urban spatial increment expanding and stock updating process in which avoiding waste and destroying environment is conscious.This process can be understood from two levels:one is the increase of quantity,characterized by concentration of population,expansion of space;the other is optimization of quality,characterized by optimization of spatial structure,equality of the society and improvement of ecological environment.By planning,controlling,directing spatial development,a sustainable development and comfortable urban space environment will become a reality.

2 Introspection of existing researches

2.1 Process discussion

In the execution level,urban planning management system lacks legal framework to support goals of low-carbon in their implementation in detailed planning.To cope with the climate change,it is necessary to identify the depth and elasticity of planning policies first,and then find out operational planning methods and instruments.Finally,adjust traditional decision-making process with new ideas and measures before establish low-carbon urban planning procedure.Specifically,three steps should be followed:①analyze:evaluate the impact of global climate change on social,economy and environment[5];②regulate:encourage the planning,designing and constructing methods that are energy-efficient in practice;③evaluate:establish the mechanism that urban development(include individual project,building,transportation system,industry,energy supply system)are evaluated and regulated,and adjust planning methods from the feed-backs.

2.2 Progress of recent studies

In theoretical research aspect,Jenny Crawford and Will French discussed the relationship between Britain spatial planning and low-carbon objective[6].Glaeser and Kahn studied 66 American metropolis areas,a certain coupling relationship between American functional area and emission level of carbon was found[7].Low-carbon Urban Development Strategy of China directed by Urban Research Association of China put forward three classes of strategies to optimize urban spatial organization.Pan Haixiao etc.put forward low-carbon spatial planning strategies for China's cities,and analyzed planning methods and technical standards from three levels of regional planning,urban planning and detailed planning[8].Combined with general problems appeared in the urban spatial planning practices,they proposed suggestion on urban transportation and land utilization,density control and combination of function areas to improve urban spatial organization[9].Gu Chaolin etc.pointed out that the planning of infrastructure in low-carbon cities should pay special attention to the planning of low-carbon energy systems[10].

In practice aspect,decision makers lack the knowledge of climate change and energy safety behind the objective of carbon emission reduction,and they have not appreciated the urgency of developing low carbon economy yet.Low-carbon urban construction is often simply equaled with circular economy and saving energy and reducing pollutants discharge,neglecting systematic arrangement.

2.3 Re-straighten

According to the above achievements in both theoretical researches and practical experiences,this paper put forward four strategic points as follows:①intensification of urban spatial function:reduce the phenomenon of occupying cultivated land,avoid dispersed,disordered and redundant development;②rationalization of urban spatial structure:the spatial organization of various types of land,the relationship between urban land use and transportation structure and the proportion of various types of land should be reasonably planned;③ordering the growth of urban space:regulate and control the construction projects,arrange the development direction and scale properly[7];④integrating the utilization of land resources:ensure comprehensive benefits of economy,social and environment in the development and utilization of urban land.

3 Explore the path:a case study of low-carbon spatial construction in Xi'an

3.1 Foundation in reality

Xi'an is one of the largest inland cities in China,which is located in the southern part of the Guanzhong Plain and center of Europe and Asia continental bridge.Xi'an is an important base of scientific and research,higher education,science,technology and industry of national defense and high and new technology industries.Besides,Xi'an is center of finance,science and technology,education,tourism and commerce that radiating mid western areas in north China.With the rapid development of urbanization course,the population of Xi'an's surrounding region immigrates rapidly to the municipal area,and the urban space expands quickly to its surrounding area.The change of the city's inner function made the scope of living and working areas extend,the relation between urban and rural areas tightened,and the demand of traffic and travel grow.Lacking of regional planning control will cause heavy pollution and heavy energy consumption.Besides,municipal system planning should stress mutual adaptation of public transportation network and municipal spatial organization pattern.Finally,the adjustment of regional spatial construction should be coordinated with employment and habitation planning to achieve the object of low-carbon[11].

3.2 Solutions

Urban spatial rational growth and low-carbon development rely heavily on the control and guide of urban planning and support and adjustment of government policies.Specifically,measures of reducing carbon dioxide emission can be divided into three scales:architecture scale,urban scale and region scale.Changes must be made in technique in the exploration of plan and design model(fig.1).

(1)In urban group space level,regulation should be strengthened between old and new cities,among big cities,and in big cities,middles mall cities and broad areas of country and town.Climate change should be taken into account in the strategy of Xi'an's spatial development strategies,and consider the problem of reducing greenhouse gas emission from the city level.Abide by the law of economy development and population grow th to taking effective measures such as control urban spatial expansion by lengthening the boundary,and organize the spatial function by identifying division of labor.

fig.1 Low-carbon City Construction Design

fig.2 Optimization Design for Xi'an-Xianyang Corridors Location

(2)In urban external space level,Xi'an's external space will extend to three directions in the future:southwest,northeast and northeast to the area of Wei River valley.The development of southwest area will be promoted by the development of Xi'an high and new technology industrial development zone,the construction of Xi'an-Hanzhong high way.There is some construction land in the northeast,and the development of south west area can be combined with the construction of logistics centre.The spatial structure is changing from point-axis system to axis-net system.In this level,rigid limitation of ecological infrastructure should be strengthened to restrain the expansion of urban space and utilization of urban land.By constructing ecological grid hierarchically,provide supporting resources and services for the city's sustainable development.Planners should resort to compact,multi-element planning patterns such as EOD,TOD,SOD and AOD to organize the urban space intensively and renew ecological order.Besides,rail traffic should perform an important function by organizing public traffic network and hinge scientifically which combining ordinary public traffic,pedestrian system and storage battery auto cycle system[12](fig.2).

(3)In the urban major space level,restrict the utilization of urban land strictly,encourage mixed,diversified urban utilization patterns,and reduce travel distance to construct short path urban space.Different kinds of spatial expansion patterns not only cause urban space expand rapidly[13],but also promote the change of space expansion patterns.Thus,it is necessary to introduce spatial design strategies into spatial planning.

4 Epilogue

Urban spatial expansion in a low-carbon manner is not only a world-wide revolution that refers to mode of production,life style,values,interests of state and destiny of mankind,but also a necessary step from high-carbon energy stage to low-carbon energy stage.With large scale applications of renewable energy such as light energy,wind energy and so on,human society will certainly progress from industrial civilization characterized by high-carbon to ecological civilization characterized by low-carbon economy and society.Low-carbon development of urban space relies heavily on the control and direction of urban planning.This paper probes into the change of technical route in regulating urban spatial grow th.Crux of the problem in China's urban spatial growth is primary in planning,causing extensive spatial development.Thus,some useful discussion of planning range,planning process,planning idea,planning point,planning pattern and planning function is solid foundation for future work.

[1]Caltho rpe Peter,Fulton William.T he Regional City-Planning fo r the End of Sorawl[M].Island Press,2001.

[2]Button K J.Urban Economics:Theory and Policy[M].Shanghai:The Commercial Press,1984.

[3]Castells Manuel.The Rise of the Network Society[M].Wiley,1996.

[4]SHEN Qing-ji,AN Chao,LIU Chang-shou.A Discussion on the Connotation,Characteristics,and Basic Principles of Planning/Construction of the Low Carbon Eco-city[J].U rban Planning Forum,2010(5):48-53.

[5]Krier Rob.T own Spaces:Contemporary Interpretations in Traditional Urbanism[M].Birkhäuser Architecture,2006.

[6]Jenny Crawford,Will French.A low-carbon future:Spatial planning's role in enhancing technological innovation in the built environment[J].Engery Policy,2008(12):4574-4579.

[7]Glaeser E L,Kahn M E.The greenness of cities:carbon dioxide emissions and urban development[EB/OL].http://en,scientific commons.o rg,2008-08-06.

[8]PAN Hai-xiao,TANG Yang.Spatial Planning Strategy for “Low Carbon Cities” in China[J].Urban Planning Forum,2008(6):57-64.

[9]ZHANG Quan,YE Xing-ping,CHEN Guo-wei.Low-carbon Urban Planning:A New Vision[J].Urban Planning,2010,(2):10-34.

[10]GU Chao-lin,TAN Zong-bo.A Study on Climate Change,Carbon Emissions and Low-carbon City Planning[J].Urban Planning Forum,2009(3):38-44.

[11]Szold Terry S,A rmando Carbonell.Smart Growth:Form and Consequences[M].Lincoln Institute of Lane Policy,2002.

[12]Sustainable Development Strategy Study Group of Chinese Academy of Sciences.China Sustainable Decelopment Strategy Report 2009[M].Beijing:The Science Press,2009.in chinese:71-74.

[13]QIU Bao-xing.Create a Low-carbon Society to Enhance National Competitiveness——British Experience of Greenhouse Gas Emission Reduction and Enlightenment[J].U rban Studies,2008(2):23-33.