The Vulcan Version 3.0 High-Resolution Fossil Fuel CO₂ Emissions for the United States

Abstract. Estimates of greenhouse gas emissions, quantified at fine space and time scales, has become a critical component of new multi-constraint flux information systems in addition to providing relevant information to decisionmakers when considering GHG mitigation opportunities. The Vulcan Project is an effort to estimate bottom-up fossil fuel emissions and CO₂ emissions from cement production (FFCO₂) for the entire United States landscape at space and time scales that satisfy both scientific and policy needs. Here, we report on version 3.0 of the Vulcan emissions which quantifies FFCO₂ emissions for the U.S. at a spatial resolution of 1 km × 1 km and hourly temporal resolution for the 2010–2015 time period. We provide a complete description of the updated methods, data sources, results, and comparison to a global gridded FFCO₂ data product. We estimate FFCO₂ emissions for the year 2011 of 1589.3 TgC with a 95 % confidence interval of 1299/1917 TgC (+18.3 %/−20.6 %), implying a one-sigma uncertainty of ~±10%. We find that per capita FFCO₂ emissions are larger in states dominated by the electricity production and industrial sectors and smaller in states dominated by onroad and residential/commercial building emissions. The center of mass (CoM) of FFCO₂ emissions in the US are located in the state of Missouri with mean seasonality that moves on a NE/SW near-elliptical path. Comparison to ODIAC, a global gridded FFCO₂ emissions estimate shows large differences in both total emissions (100.1 TgC for year 2011) and spatial patterns. The spatial correlation (R²) between the two data products was 0.38 and the mean absolute difference at the individual gridcell scale was 80.04 %. The Vulcan v3.0 FFCO₂ emissions data product offers an immediate high-resolution estimate of emissions in every city within the U.S., providing a large potential savings of time and effort for cities planning to develop self-reported city inventories. The Vulcan v3.0 annual gridded emissions data product can be downloaded from the data repository at Oak Ridge National Laboratory (https://doi.org/10.3334/ORNLDAAC/1741, Gurney et al., 2019).