Uncertainty and sensitivity analysis of modeling plant CO₂ exchange in the built environment

The dynamics of carbon dioxide (CO₂) exchange in the built environment, coupled with local microclimate modeling, is of critical importance to the understanding of emergent patterns of longterm urban climate evolution. In addition to the complex model physics, the difficulty is outstanding to characterize uncertainties inherited in the parameter space and its impact on the model performance and predictive skills. In this study, we conducted a series of numerical simulations based on advanced Markov chain Monte Carlo algorithms to quantify the sensitivity of a recently developed modeling framework by coupling the dynamics of CO₂ transport into a single-layer urban canopy model. The results show that urban morphology (canyon aspect ratio), irrigation, and the physiological properties of urban vegetation predominate the processes of plant CO₂ exchange in the built environment. In contrast, the CO₂ budget is relatively insensitive to material properties of urban facets in the built environment. The findings in this study can help to unravel the interplay of urban carbon dynamics and the built environment, as well as to inform researchers and policy makers for sustainable urban development towards a low carbon city.