城市复合生态系统碳氧平衡分析——以沿海城市厦门为例

Analysis of the carbon and oxygen balance of a complex urban ecosystem:A case study in the coastal city of Xiamen

通过综合城市复合生态系统内社会经济活动的主要排碳、耗氧行为,以及城市区域内湿地、淡水、海洋、森林和农田5种遗留自然生态系统的固碳释氧功能,构建了城市碳氧平衡分析模型(UCOB),并估算了城市社会经济活动和城市中自然生态系统的碳氧收支,对城市生态系统平衡状况进行定量化指征.最后,以中国东南沿海城市厦门为例进行研究.结果显示:厦门市2007年碳平衡系数为9.03,即二氧化碳释放量是其所能吸收能力的9.03倍;氧平衡系数为5.78,即社会经济活动消耗的氧气是当地自然生态系统所能提供氧气量的5.78倍.如果不考虑电力消耗产生间接排碳耗氧数量,厦门市2007年全市碳平衡系数为5.26,氧平衡系数为1.47.由于社会经济活动功能和自然生态系统分布的差异,厦门市6个行政分区的碳氧平衡产生显著的差异.其中,作为老工业区的湖里区碳氧失衡状况最显著,如不考虑间接排碳耗氧量,作为新兴工业区的海沧区碳氧失衡最严重;位于城市郊区的同安区和翔安区由于保存大面积自然生态系统,碳氧平衡状况相对良好.最后,从城市定位和分区功能对厦门城市碳氧平衡未来发展及其对策进行了探讨.本文将有助于深入理解城市生态系统中碳氧平衡状况,指导合理的城市总体规划和功能分区,为实现持续低碳城市化提供科学依据.

Through combining the major oxygen consumption and carbon emission of socioeconomic activities and the carbon sequestration and oxygen emission of five remnant natural ecosystems in a complex urban ecosystem,we built an urban carbon and oxygen balance model（UCOB） to estimate the input and output of carbon and oxygen and to quantitatively indicate the ecological balance of an urban ecosystem.The results from a case study of Xiamen,a coastal city in southeastern China,showed：In 2007,the carbon balance index and oxygen balance index of the city were 9.03 and 5.78 respectively,which means the total amount of oxygen consumption and carbon emission from urban socioeconomic activities were 9.03 and 5.78 times greater than the amount of natural oxygen emission and carbon sequestration in Xiamen,respectively.Without considering the indirect oxygen consumption and carbon emission from electricity consumption,the balance indices of carbon and oxygen of Xiamen City were 5.26 and 1.47 respectively.Carbon and oxygen balance indices showed a significant variation among the six administrative districts of Xiamen,because of differences in their socioeconomic functions and distribution of natural ecosystems.As an old industrial zone,Huli district suffered the highest imbalance of carbon and oxygen.Without considering the indirect oxygen consumption and carbon emission,Haicang district,a newly emerged industrial area,was the worst.Located in the suburban area and possessing large areas of natural vegetation cover,Tongan district and Xiangan district had the best carbon and oxygen balance.The future development of carbon and oxygen balance in Xiamen is discussed,as well as possible control measures based on the city orientation and major function zoning.We hope this paper can contribute to a better understanding of the carbon and oxygen balance of a complex urban ecosystem,providing the scientific basis for rational urban overall planning and function division to establish low-carbon and sustainable urbanization.