Characterisation of gas reference materials for underpinning atmospheric measurements of stable isotopes of nitrous oxide

Abstract. The precise measurement of the amount fraction atmospheric nitrous oxide (N2O) is required to understand global emission trends. Analysis site-specific stable isotopic composition N2O provides a means differentiate sources. availability accurate reference materials known fractions and critical for achieving these goals. We present development gas underpinning measurements isotope ratio. Uncertainties target World Metrological Organisation Global Atmosphere Watch (WMO-GAW) compatibility goal 0.1 nmol mol−1 extended 0.3 mol−1, in an range 325–335 mol−1. also demonstrate stability ratio characterisation study cavity ring-down spectrometer used analysis materials.