Spatial Variability in Greenhouse Gas Concentrations over Three Regions in the Eastern US

CO₂ and CH₄ are two major greenhouse gases that have had a major contribution to climate change, leading to an interest in understanding the carbon cycle to understand and perhaps mitigate climate-change. The ACT-America flight campaigns revealed that there are large and complex spatial patterns of these gases, which are not well understood. This paper analyzes the relationship of CO₂, CH₄, and CO measurements taken during the ACT-America campaign in summer 2016 to explore the causes of variations in greenhouse gases mole fractions and ultimately better quantify sources and sinks of these gases. Trace gas correlations in the free troposphere have a more negative slope and correlation compared to those in the atmospheric boundary layer. Boundary layer mean mole fractions exhibit more variability than the mean mole fractions in the troposphere, converging with increasing altitude to smaller range of concentrations. The complex correlations between these gases imply that there are multiple mechanisms occurring that can vary depending on the region and the portion of the atmosphere being observed.