期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：38
DOI：10.1073/pnas.2202338119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
Large methane point sources exist across multiple source sectors (e.g., oil, gas, coal, livestock, waste). Lacking is a robust assessment of the relative contribution of strong methane point sources against total or regional budgets, which is needed for prioritizing mitigation. In this study, we flew airborne imaging spectrometers repeatedly over multiple basins in the United States to quantify large methane point sources across multiple sectors. We compared these point sources to satellite-based regional flux inversions and found that methane super-emitters consistently make up a sizable contribution to total the total flux in a basin. These results show that a significant climate benefit can be realized by specific isolation and remediation of relatively few sources.
Understanding, prioritizing, and mitigating methane (CH
4) emissions requires quantifying CH
4 budgets from facility scales to regional scales with the ability to differentiate between source sectors. We deployed a tiered observing system for multiple basins in the United States (San Joaquin Valley, Uinta, Denver-Julesburg, Permian, Marcellus). We quantify strong point source emissions (>10 kg CH
4 h
−1) using airborne imaging spectrometers, attribute them to sectors, and assess their intermittency with multiple revisits. We compare these point source emissions to total basin CH
4 fluxes derived from inversion of Sentinel-5p satellite CH
4 observations. Across basins, point sources make up on average 40% of the regional flux. We sampled some basins several times across multiple months and years and find a distinct bimodal structure to emission timescales: the total point source budget is split nearly in half by short-lasting and long-lasting emission events. With the increasing airborne and satellite observing capabilities planned for the near future, tiered observing systems will more fully quantify and attribute CH
4 emissions from facility to regional scales, which is needed to effectively and efficiently reduce methane emissions.
