Atmospheric measurements of greenhouse gases (GHGs) are routinely incorporated into atmospheric chemistry transport modelling systems to estimate sources and sinks at various temporal and spatial scales (the so called ‘top-down’ approach). Top-down approaches are important as they provide independent emission estimates that are consistent with the observed changes in the atmosphere. However, temporal variations in GHG mixing ratios alone only provide a weak constraint (if at all) on the sources. Information on the contribution from specific sources and processes is vital to aid effective and timely policy for mitigating emissions. The attribution of atmospheric GHG mixing ratio changes to anthropogenic or natural sources, and to source sectors, can be aided by the measurement and interpretation of isotope ratios of the GHG (e.g. stable isotopes of CH4, N2O or radio-carbon for CO2) or of gaseous tracers that are correlated with sources or sinks of the target pollutant (e.g. atmospheric potential oxygen - APO for CO2 or ethane for CH4).
This session invites contributions from the community working on the use of isotope ratios and other tracers in understanding the sources / sinks of GHGs to the atmosphere. This includes but is not limited to:
- Advances in analytics for GHG isotope ratios or tracers including developments in metrology, e.g. reference materials or methods, to improve sustainability of monitoring,
- Incorporation of isotope or trace gas measurements into models for improved understanding of the sources and/or sinks,
- Studies contributing data on GHG isotope ratio source signatures or tracer/target species emission factors.