High resolution fossil fuel combustion CO₂ emission fluxes for the United States

Quantification of fossil fuel CO₂ emissions at fine space and time resolution is emerging as a critical need in carbon cycle and climate change research. As atmospheric CO₂ measurements expand with the advent of a dedicated remote sensing platform and denser in situ measurements, the ability to close the carbon budget at spatial scales of ∼100 km² and daily time scales requires fossil fuel CO₂ inventories at commensurate resolution. Additionally, the growing interest in U.S. climate change policy measures are best served by emissions that are tied to the driving processes in space and time. Here we introduce a high resolution data product (the “Vulcan” inventory) that has quantified fossil fuel CO₂ emissions for the contiguous U.S. at spatial scales less than 100 km² and temporal scales as small as hours. This data product, completed for the year 2002, includes detail on combustion technology and 48 fuel types through all sectors of the U.S. economy. The Vulcan inventory is built from the decades of local/regional air pollution monitoring and complements these data with census, traffic, and digital road data sets. The Vulcan inventory shows excellent agreement with national-level Department of Energy inventories, despite the different approach taken by the DOE to quantify U.S. fossil fuel CO₂ emissions. Comparison to the global 1° × 1° fossil fuel CO₂ inventory, used widely by the carbon cycle and climate change community prior to the construction of the Vulcan inventory, highlights the space/time biases inherent in the population-based approach.