Regional Nitrous Oxide Emissions and Its Biogeochemical Fingerprints

Agricultural systems are having a profound influence on global anthropogenic nitrous oxide (N₂O) emissions. Nitrous oxide is a greenhouse gas and a stratospheric ozone depleting substance. Nitrous oxide concentrations have increased rapidly due to growing synthetic nitrogen use. Emissions are episodic and driven by complex biogeochemical processes involving direct and indirect pathways. Here, we used relatively long-term trace gas observations from a tall tower (244 m) located within the US Corn Belt in combination with chemical transport modeling and novel isotopocule measurements to: 1) constrain the emissions; 2) assess their seasonal and inter-annual variability in response to climate and land management and; 3) better understand the biogeochemical processes controlling the temporal variability. Relatively long-term (2010 to 2023) N₂O observations and chemical transport modeling are used to estimate emissions while recent (2022 to 2023) N₂O isotopocule observations are used to provide insights into the biogeochemical fingerprints of N₂O emissions within the region.