Detecting fossil fuel emissions patterns from subcontinental regions using North American in situ CO(2) measurements

The ability to monitor fossil fuel carbon dioxide (FFCO(2)) emissions from subcontinental regions using atmospheric CO(2) 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 FFCO(2) emissions from subcontinental regions. Detectability is evaluated by examining the degree to which FFCO(2) emissions patterns from specific regions are needed to explain the variability observed in high-frequency atmospheric CO(2) observations. Analyses using a CO(2) monitoring network of 35 continuous measurement towers over North America show that FFCO(2) emissions are difficult to detect during nonwinter months. We find that the compounding effects of the seasonality of atmospheric transport patterns and the biospheric CO(2) flux signal dramatically hamper the detectability of FFCO(2) 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 FFCO(2) emissions detection and estimation is to be achieved beyond urban scales. KEY POINTS: Poor detectability of fossil fuel CO(2) emissions from subcontinental regions. Detectability assessed via attribution of emissions patterns in atmospheric data. Loss in detectability due to transport modeling errors and biospheric signal;