Seasonal Variations of Methane Emissions from a Urumqi Landfill in China and its driving factors using Hyperspectral Satellite Time-Series Observations

Methane emissions from landfills represent a crucial yet inadequately quantified component of the global methane budget. Hyperspectral satellites offer advanced monitoring capabilities that capture complete plumes from landfill point sources. Despite their potential, studies using hyperspectral satellites for long-term monitoring of landfill methane emissions remain scarce. This study presents the first long-term time series of methane emissions from the Urumqi landfill in China using five high-resolution and hyperspectral satellites, with 41 observations from 2020-2024. The results show emissions follow a heavy-tailed distribution with winter super-emission events. Landfill seasonal methane emissions correlate negatively with pressure changes and positively with temperature and dew point changes. Time-series observations revealed landfill methane emissions of 0.030, 0.040, and 0.026 Tg/yr for 2022, 2023, and 2024 respectively, with ≥6 annual satellite revisits providing sufficient accuracy for yearly emission estimates. Our findings establish an optimized framework for persistent monitoring of methane emissions from landfills.