Developing an enhanced preconcentration system (RAPTOR) for high-precision tropospheric nitrous oxide isotope measurements by laser spectroscopy 

The mixing ratio of nitrous oxide (N2O), an important greenhouse gas and ozone-depleting substance, in the troposphere has increased by 25% (~336 ppb) since the preindustrial period, with increased emissions in the last few years showing that effective mitigation policies are urgently required. N2O is emitted from a range of anthropogenic sources, particularly fertilised agricultural soils. N2O sources and sinks can be constrained using measurements of four isotopocules: 14N15N16O (α), 15N14N16O (β), 14N14N16O, and 14N14N18O, and the site-specific relative isotope ratio differences (δ15Nα and δ15Nβ); however, N2O’s long tropospheric lifetime requires high precision (