城市生态系统代谢的能值研究进展

Review on the research of Emergy-based urban metabolism

城市环境问题的深层原因是城市代谢过程出现了问题。城市代谢研究,是分析城市在人类各种活动影响下,如何将取自生态系统的物质和能量进行转换、利用与处理的过程,成为评价城市可持续发展的重要依据。早在19世纪末,就有有关能量流分析社会代谢的概念;近期最具代表性的是Howard T.Odum。首先从城市代谢研究的兴起和发展出发,然后分环境评价、空间层面、动态模拟三方面,对Odum的能值方法在城市代谢分析中的应用进行了回顾。环境评价方面以生态经济学为理论基础,提出发展具有生物物理基础的能值方法,对城市代谢的生态评估更为恰当;空间层面结合景观生态学,为区域空间规划提供了参考,并指出土地利用变迁与社会代谢间的相关性研究为当前的核心问题;动态层面仍以系统生态学建立整合性系统模型为基础,但空间系统模拟方法的发展仍处于起步阶段。各个学科与方法的整合促进了城市代谢研究的进一步深化。最后,建议未来应用能值研究城市代谢的4个研究方向有:(1)城市代谢与可持续发展之间相互关系的研究;(2)城市代谢与土地利用变迁相互驱动的模型发展;(3)基于代谢过程的城市管理对策研究;(4)全球环境变迁对土地利用和城市代谢的影响。

Current research emphasizes on the hazards of environmental problems and presents it is the result of socioeconomic me- tabolism in essence. The study of urban metabolism focus on the conversion, utilization and management of materials and energy from the ecosystem by the influence of human beings. It has been the important basis of the evaluation of the city＇s sustainable de- velopment. The concept can be traced back to the end of 19th century and the most representative is Howard T.Odum in recent study. To provide a useful framework to study the interrelations between human societies and their natural environments., This paper intro- duces the emergence and development of urban metabolism. Combining the idea with emergy synthesis, concepts and methodologies of ecological analysis for environmental valuation, spatial analysis and dynamic simulation are discussed respectively. Current re- search on spatial analysis is dominated by landscape ecology as a reference of regional planning and proposes the importance of the relationships between land use and socioeconomic metabolism has also been raised recently. Current research on the dynamic aspect emphasizes on the the development of integrated system model based on systems ecology principles, but the application of spatial dynamic modeling has to be strengthened. On the foundation of ecological economics, Emergy synthesis is the main biophysical approach for environmental valuation. The integration of different approaches represents the continuing development of the disci- pline. Finally, four research questions are suggested as research agenda of the application of emergy analysis for urban metabolism：（1） interrelationships between urban metabolism and sustainable development for environmental evaluation; （2） the integrated system model for the development of ecological mechanism between urban metabolism and land use change; （3） the investigation into the policies of urban governance based on the metabolic course; （4） the influence on land use and urban metabolism from the global environmental change.