Development of an Open-Path N2O Flux Measurement System for Understanding Agricultural and Soil Emissions

Abstract:

Nitrous oxide is the third most important greenhouse gas, with an atmospheric lifetime of ~114 years and a global warming impact ~300 times greater than that of CO₂. The main cause of nitrous oxide’s atmospheric increase is anthropogenic emissions, and over 80% of the current global anthropogenic flux is related to agriculture, including associated land-use change. An accurate assessment of N₂O emissions from agriculture is vital not only for understanding the global N₂O balance and its impact on climate and also for designing crop systems with lower GHG emissions. This work focuses on the early development of an open path N₂O instrument for field deployment, based on quantum cascade laser absorption. With a targeted precision of 0.1 ppb at 10 Hz, this instrument will enable eddy covariance measurements to determine vertical fluxes of N₂O. Details of the instrument design, which emphasizes ruggedness and high thermal stability, will be presented along with initial results from outdoor testing of the instrument.