Inverse modelling of CF₄ and NF₃ emissions in East Asia

Decadal trends in the atmospheric abundances of carbon tetrafluoride (CF₄) and nitrogen trifluoride (NF₃) have been well characterised and have provided a time series of global total emissions. Information on locations of emissions contributing to the global total, however, is currently poor. We use a unique set of measurements between 2008 and 2015 from the Gosan station, Jeju Island, South Korea (part of the Advanced Global Atmospheric Gases Experiment network), together with an atmospheric transport model, to make spatially disaggregated emission estimates of these gases in East Asia. Due to the poor availability of good prior information for this study, our emission estimates are largely influenced by the atmospheric measurements. Notably, we are able to highlight emission hotspots of NF₃ and CF₄ in South Korea due to the measurement location. We calculate emissions of CF₄ to be quite constant between the years 2008 and 2015 for both China and South Korea, with 2015 emissions calculated at 4.3±2.7 and 0.36±0.11 Gg yr^-1, respectively. Emission estimates of NF₃ from South Korea could be made with relatively small uncertainty at 0.6±0.07 Gg yr^-1 in 2015, which equates to ∼ 1.6 % of the country's CO₂ emissions. We also apply our method to calculate emissions of CHF₃ (HFC-23) between 2008 and 2012, for which our results find good agreement with other studies and which helps support our choice in methodology for CF₄ and NF₃..