2010-2016 methane trends over Canada, the United States, and Mexico observed by the GOSAT satellite: contributions from different source sectors
journal contributionposted on 2019-08-01, 14:13 authored by J-X Sheng, DJ Jacob, AJ Turner, JD Maasakkers, J Benmergui, AA Bloom, C Arndt, R Gautam, D Zavala-Araiza, H Boesch, RJ Parker
We use 7 years (2010–2016) of methane column observations from the Greenhouse Gases Observing Satellite (GOSAT) to examine trends in atmospheric methane concentrations over North America and infer trends in emissions. Local methane enhancements above background are diagnosed in the GOSAT data on a 0.5∘×0.5∘ grid by estimating the local background as the low (10th–25th) percentiles of the deseasonalized frequency distributions of the data for individual years. Trends in methane enhancements on the 0.5∘×0.5∘ grid are then aggregated nationally and for individual source sectors, using information from state-of-science bottom-up inventories. We find that US methane emissions increased by 2.5±1.4 % a−1 (mean ± 1 standard deviation) over the 7-year period, with contributions from both oil–gas systems (possibly unconventional oil–gas production) and from livestock in the Midwest (possibly swine manure management). Mexican emissions show a decrease that can be attributed to a decreasing cattle population. Canadian emissions show year-to-year variability driven by wetland emissions and correlated with wetland areal extent. The US emission trends inferred from the GOSAT data account for about 20 % of the observed increase in global methane over the 2010–2016 period.
This work was supported by the NASA Earth Science Division and by the Environmental Defense Fund. Part of the funding for this study was provided through NASA grant no. NNH14ZDA001N-CMS. Jian-Xiong Sheng and Claudia Arndt were partially funded by the Kravis Scientific Research Fund at the Environmental Defense Fund. Funding for EDF's work on livestock methane was provided by Sue and Steve Mandel. Alexander J. Turner was supported by a Department of Energy (DOE) Computational Science Graduate Fellowship (CSGF). Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Robert J. Parker was funded via an ESA Living Planet Fellowship with additional funding from the UK National Centre for Earth Observation (NCEO) and the ESA Greenhouse Gas Climate Change Initiative (GHG-CCI).
CitationAtmospheric Chemistry and Physics, 2018, 18 (16), pp. 12257-12267 (11)
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
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