2010–2015 North American methane emissions, sectoral contributions, and trends: a high-resolution inversion of GOSAT observations of atmospheric methane
Name
acp-21-4339-2021.pdf
Description
Published version
Size
4.7 MB
Format
Adobe PDF
Checksum (MD5)
a44fcda30c3d52ac2deb660b451affb2
Author(s)
Maasakkers, Joannes D
Jacob, Daniel J
Sulprizio, Melissa P
Scarpelli, Tia R
Nesser, Hannah
Sheng, Jianxiong
Zhang, Yuzhong
Lu, Xiao
Bloom, A Anthony
Bowman, Kevin W
Date Issued
March 22, 2021
Journal
Atmospheric Chemistry and Physics
Publisher
Copernicus GmbH
Citation
Maasakkers, J. D., Jacob, D. J., Sulprizio, M. P., Scarpelli, T. R., Nesser, H., Sheng, J., Zhang, Y., Lu, X., Bloom, A. A., Bowman, K. W., Worden, J. R., and Parker, R. J.: 2010–2015 North American methane emissions, sectoral contributions, and trends: a high-resolution inversion of GOSAT observations of atmospheric methane, Atmos. Chem. Phys., 21, 4339–4356
Version
Final published version
Abstract
We use 2010–2015 Greenhouse Gases Observing Satellite (GOSAT) observations of atmospheric methane columns over North America in a high-resolution inversion of methane emissions, including contributions from different sectors and their trends over the period. The inversion involves an analytical solution to the Bayesian optimization problem for a Gaussian mixture model (GMM) of the emission field with up to 0.5 ◦ ×0.625◦ resolution in concentrated source regions. The analytical solution provides a closedform characterization of the information content from the inversion and facilitates the construction of a large ensemble of solutions exploring the effect of different uncertainties and assumptions in the inverse analysis. Prior estimates for the inversion include a gridded version of the Environmental Protection Agency (EPA) Inventory of US Greenhouse Gas Emissions and Sinks (GHGI) and the WetCHARTs model ensemble for wetlands. Our best estimate for mean 2010– 2015 US anthropogenic emissions is 30.6 (range: 29.4– 31.3) Tg a−1 , slightly higher than the gridded EPA inventory (28.7 (26.4–36.2) Tg a−1 ). The main discrepancy is for the oil and gas production sectors, where we find higher emissions than the GHGI by 35 % and 22 %, respectively. The most recent version of the EPA GHGI revises downward its estimate of emissions from oil production, and we find that these are lower than our estimate by a factor of 2. Our best estimate of US wetland emissions is 10.2 (5.6–11.1) Tg a−1 , on the low end of the prior WetCHARTs inventory uncertainty range (14.2 (3.3–32.4) Tg a−1 ), which calls for better understanding of these emissions. We find an increasing trend in US anthropogenic emissions over 2010–2015 of 0.4 % a−1 , lower than previous GOSAT-based estimates but opposite to the decrease reported by the EPA GHGI. Most of this increase appears driven by unconventional oil and gas production in the eastern US. We also find that oil and gas production emissions in Mexico are higher than in the nationally reported inventory, though there is evidence for a 2010–2015 decrease in emissions from offshore oil production.
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.5194/acp-21-4339-2021
