Abstract

Northern wetlands are one of the largest sources of methane (CH₄), a potent greenhouse gas, and are subject to ongoing rapid climate change. This study attempted to evaluate the CH₄ emissions from northern Eurasia using a process-based terrestrial biogeochemical model and satellite-derived, high-resolution inundation data. Total CH₄ emissions from the inundation area were estimated to be 8.5 Tg CH₄ yr–¹ during 2003–2017, with a substantial range of interannual variability (± 0.7 Tg CH₄ yr–¹). Compared with an estimate based on ground flux measurements, the present model estimation satisfactorily captured fine-scale spatial variation associated with land cover and topography, although smaller inundation in the lowlands could lead to an underestimation of emissions. The seasonal change of CH₄ emissions from negligible rates during cold seasons to high rates in warm seasons was adequately captured during the model simulation. The interannual variability could be associated with broad-scale meteorological events (e.g., high emissions in 2015, the El Niño year), but no long-term trend was found in the annual emissions. This study demonstrated that combining satellite data with a process-based model is effective way to quantify CH₄ emissions in remote extensive areas, although further research and development are required for observational detection of inundation and modeling of biogeochemical processes.