Open-data-based city-scale gridded carbon dioxide emission inventory: supporting urban carbon monitoring in Chengdu, China

Gridded carbon dioxide (CO2) emission inventories are usually required as prior information for deriving urban-scale emissions from atmospheric CO2 monitoring data. However, existing global or national gridded inventories are inadequate for this purpose because of their failure to accurately resolve the spatial distribution of urban emissions, especially from point sources, at the city scale. To address this challenge, we developed a city-scale gridded CO2 emission inventory mode that spatially disaggregated sectorial CO2 emissions of a city to a high-resolution grid. We compiled a series of sector-specific, high-resolution proxies for spatial disaggregation by integrating multiple open data, including remote sensing imagery and urban big data. As a demonstration, we applied the methodology to Chengdu, China, for a gridded CO2 emission inventory at a 1 km resolution for 2020. This inventory offered a clear and comprehensive depiction of the spatial distribution of CO2 emissions at the city scale, identified high-emission areas, and delivered essential scientific support and decision-making tools for effective carbon management. For example, compared to global or national inventories (e.g., EDGAR) that use population or GDP as proxy data for industrial emissions, this inventory provided more accurate locations of industrial point source emissions by including information on 50,000 industrial sources collected from open sources. The improved spatial distribution of the gridded inventory allows for more accurate and reliable flux inversion, establishing a robust data foundation for the development of CO2 concentration monitoring networks.