The application of spatially explicit networks to compare carbon flows: A case study in Beijing, China.

In this paper, we analyzed the similarities and differences between spatially explicit 8- and 18-node models of an urban carbon metabolic network. The results reveal the influence of different divisions of a system on heterogeneity in carbon flows along metabolic pathways within the network. Paths of 18-node network were between 3 and 5 times than those of the 8-node network with 4% or less differences in carbon flows. The 8-node model provided a good overview of the system and revealed the key paths. However, it also concealed some important flows. In contrast, the 18-node model revealed the details of the flows and clarified the amplification effect of the socioeconomic components and the masking of the effect of natural components that occurred in the 8-node model. However, it was too complex to clearly reveal the key interactions. Therefore, we can choose the optimal division of a network model based on the specific problems we are trying to solve and the specific context. The application of 18-node network is suitable for moderately mature cities which are under the pressure of consolidation and urban adjustment. The 8-node model can be used to provide an overview that will reveal where to focus on using the 18-node model, which provides more details and better support for the formulation of concrete measures. Image 1 • Carbon flows of 8- and 18-node networks of urban metabolism were compared. • The division always increase the contribution of natural components. • Contributions of artificial components changes variously after division. • The application of 18-node network is suitable for moderately mature cities. • The 8-node network could present the key activity of fast urbanization cities. [ABSTRACT FROM AUTHOR]