Modelling wetland methane emission estimates by leveraging new observations of anthropogenic point-source plumes

Abstract. Satellite retrieval capabilities for detecting methane (CH₄) diffuse and point sources have increased drastically over the last decade. These observations are playing an important role in atmospheric inversion systems to optimize emissions from anthropogenic and natural sources. A critical component of atmospheric inverse modelling is the prior estimate of CH₄ emissions, which impact both the magnitude of posterior emissions and the distribution between sectors, including wetland emissions. Here we utilize point source retrievals from GHGSat to update prior emission estimate for fossil fuels. We demonstrate the effect on posterior emission using the Integrated Methane Inversion for the Western Siberian Lowlands. The updated GHGSat-informed fossil prior results in a reduction in wetland CH₄ flux of 0.59 Tg CH4 yr^-1. The approach demonstrates the potential impact of large point sources, that are typically not accounted for in bottom-up emission inventories. Due to modelling approaches adjusting anthropogenic and natural sources at the state vector level, input proportion of these sectors is critical for understanding regional methane budgets and the effect of climate change on wetland emissions.