Metrology for harmonisation of field isotope ratio measurements
Climate change is a major threat facing society. The atmospheric burden of greenhouse gases (GHGs), such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), is continuously increasing due to anthropogenic emissions, thereby causing global warming. Therefore, a reduction of emissions is urgently needed. Measurements of isotopic ratios offer the possibility of discriminating anthropogenic from natural contributions of GHGs. However, harmonised and standardised field calibration and measurement methods are required to support measurements networks such as Integrated Carbon Observation System (ICOS) and National Oceanic and Atmospheric Administration (NOAA). The aim of the project is to develop a metrological infrastructure (reference materials, guidelines, methods) that is directly linked to monitoring networks such as ICOS to harmonised field isotope ratio measurements.
Objectives of the project:
The overall aim of the project is to develop a metrological infrastructure (reference materials, guidelines, methods) that is directly linked to monitoring networks such as the Integrated Carbon Observation System (ICOS) to harmonised field isotope ratio measurements. The specific objectives of the project are:
1. To develop improved metrological measurement approaches, improved isotope Certified Reference Materials (CRMs) for N2O, CO2 and CH4 and guidelines for the harmonisation of in-situ field measurements of greenhouse gas isotope ratios by identifying current deficiencies in data accuracy and reliability and the requirements of networks making field-based isotope measurements. (WP1)
2. To develop metrological measurement methods to link site-specific isotopic composition (δ15NSP) in N2O CRMs to international isotope ratio scales with a target uncertainty of < 1.0 ‰. CRMs identified in objective 1 will be used for calibration. (WP1)
3. To develop instruments as well as test and validate improved metrological measurement methods (optical and mass spectrometry including instrumentation) for field isotope ratio measurements for N2O, CO2 and CH4 targeting repeatability better than WMO compatibility goals (δ13C-CO2 0.01 ‰, δ 18O-CO2 0.05 ‰, δ13C-CH4 0.02 ‰, δ2H-CH4 1.0 ‰) and 0.1 ‰, for δ15N and δ18O-N2O and 0.2 ‰ for δ 15NSP. CRMs from objective 1 will be used for calibration. (WP2)
4. To implement metrological harmonised measurement approaches and guidelines developed in WP1 as well as methods developed in WP2 for Greenhouse gases (GHGs) isotope ratio measurements at field sites (e.g. ICOS station Jungfraujoch and ICOS Cities Zurich). Measurements will be performed at existing field sites in e.g. the Integrated Carbon Observation System (ICOS) network to achieve improved compatibility of field site measurements with target compatibility goals (to meet WMO extended compatibility goals) better than 0.2 ‰ for δ15N and δ18O-N2O, 1 ‰ for δ15NSP, 0.1 ‰ for δ13C-CO2 and δ18O-CO2, 0.2 ‰ for δ13C-CH4 and 5 ‰ for δ2H-CH4 (WP3).
5. To facilitate the take up of the technology and measurement infrastructure developed in the project by the measurement supply chain (instrument manufacturers), standards developing organisations (CEN, ISO), and end users (e.g. ICOS, IAEA, WMO-GAW). (WP4)
The publishable summary can be downloaded here.