Advancements in Satellite-Based CO2 Monitoring: OCO-2 and OCO-3 Observations and Their Role in Urban Emission Quantification

Recent advancements in satellite-based CO₂ observations have significantly improved our ability to quantify local and urban emissions. In recent years, methodological advancements have included linking total column CO₂ (XCO₂) observations to emission sources, deriving emission estimates that are less dependent on prior inventories, using solar-induced fluorescence (SIF) to distinguish between biospheric and anthropogenic fluxes in cities, and resolving fine-scale urban CO₂ gradients to attribute emissions to specific sectors. Together, these developments lead to more accurate and reliable emission estimates from space in urban areas.

Long term OCO-2 and OCO-3 XCO₂ measurements have been particularly valuable in advancing urban CO₂ studies. Further, OCO-3’s Snapshot Area Mapping (SAM) observations provide high-density CO₂ measurements over targeted areas, improving our understanding of emissions from entire cities down to individual point sources. Techniques such as Gaussian plume modeling, cross-sectional flux methods, and integrated mass enhancement allow to analyze these measurements in great detail. Additionally, using multi-species approaches and combining SAM data with collocated observations of nitrogen dioxide (NO₂), carbon monoxide (CO), and other atmospheric gases from space- and ground-based sensors have the potential to provide insights into combustion efficiencies, sector-specific emissions, and more.

This presentation will cover recent advances and studies in urban CO₂ monitoring, focusing on how OCO-2 and OCO-3 observations and current methods are contributing to the development of independent satellite-based greenhouse gas measurement, reporting, and verification (MRV) systems, and discussing the limitations of current systems.