ADVANCING URBAN CARBON DIOXIDE (CO₂) INTERPRETATION FOR MODELING, MONITORING, AND EDUCATION

<p><strong>Carbon dioxide (CO₂) is the most abundant greenhouse gas (GHG) and quantifying it in the atmosphere is critical for understanding and addressing climate change. With the expansion of in-situ monitoring networks, CO₂ observations have shifted their focus on global averages to finer spatial and temporal scales, enabling better emissions quantification and tracking changes in anthropogenic emissions. While these data are used in atmospheric inverse modeling to estimate emissions, their broader potential remains underexplored. Thus, this research addresses four research questions: (1) how can the use of in-situ GHG observations be expanded beyond afternoon hours in urban-scale atmospheric inverse modeling?, (2) what types of data analysis can be used to interpret atmospheric observations of urban CO₂ mole fractions? (3) what recommendations can be made for urban CO₂ background determination?, and (4) how can in-situ observations be used beyond scientific research within the context of carbon cycle education? To address these questions, this thesis is grounded in the analysis of atmospheric observations of urban CO₂ mole fractions, to advance the monitoring, modeling, and communication of urban CO₂ emissions.</strong></p><p>With in-situ atmospheric CO₂ observations from the INFLUX (Indianapolis Flux Experiment), I establish a criterion for incorporating non-afternoon observations, such as morning rush hour peaks, into atmospheric inverse modeling. Using CO₂ observations from the Auckland greenhouse gas network in Aotearoa New Zealand, I characterize the CO₂ mole fractions at urban and background sites and recommend analysis techniques applicable to other urban networks. By combining various atmospheric CO₂ observing technologies, I demonstrate when and how atmospheric observations can be used in education context and to track emissions changes.</p><p>As such, this thesis adopts a multidisciplinary approach to improve urban CO₂ research and application, by integrating scientific, technical, and societal perspectives.</p>