Detecting fossil fuel emissions patterns from subcontinental regions using North American in situ CO₂ measurements

The ability to monitor fossil fuel carbon dioxide (FFCO₂) emissions from subcontinental regions using atmospheric CO₂ observations remains an important but unrealized goal. Here we explore a necessary but not sufficient component of this goal, namely, the basic question of the detectability of FFCO₂ emissions from subcontinental regions. Detectability is evaluated by examining the degree to which FFCO₂ emissions patterns from specific regions are needed to explain the variability observed in high-frequency atmospheric CO₂ observations. Analyses using a CO₂ monitoring network of 35 continuous measurement towers over North America show that FFCO₂ emissions are difficult to detect during nonwinter months. We find that the compounding effects of the seasonality of atmospheric transport patterns and the biospheric CO₂ flux signal dramatically hamper the detectability of FFCO₂ emissions. Results from several synthetic data case studies highlight the need for advancements in data coverage and transport model accuracy if the goal of atmospheric measurement-based FFCO₂ emissions detection and estimation is to be achieved beyond urban scales.

Poor detectability of fossil fuel CO₂ emissions from subcontinental regionsDetectability assessed via attribution of emissions patterns in atmospheric dataLoss in detectability due to transport modeling errors and biospheric signal.