Assessment of methane emissions from European countries using satellite and surface observations

Sun, Shuai; Zhang, Yuzhong; Chen, Wei; Pan, Shaomin; Pu, Dongchuan; Tong, Xin; Chen, Huilin; Houweling, Sander

doi:10.5194/acp-26-14981-2026

Articles | Volume 26, issue 20

https://doi.org/10.5194/acp-26-14981-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-26-14981-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 26, issue 20

Research article

|

23 Oct 2026

Research article |

| 23 Oct 2026

Assessment of methane emissions from European countries using satellite and surface observations

Shuai Sun, Yuzhong Zhang, Wei Chen, Shaomin Pan, Dongchuan Pu, Xin Tong, Huilin Chen, and Sander Houweling

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Final revised paper (published on 23 Oct 2026)
Supplement to the final revised paper
Preprint (discussion started on 10 Jun 2026)
Supplement to the preprint

Interactive discussion

Status: closed

RC1: 'Comment on egusphere-2026-2165', Anonymous Referee #1, 13 Jul 2026

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2165/egusphere-2026-2165-RC1-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2026-2165-RC1
RC2: 'Comment on egusphere-2026-2165', Anonymous Referee #2, 19 Jul 2026

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2165/egusphere-2026-2165-RC2-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2026-2165-RC2
AC1: 'Comment on egusphere-2026-2165', Shuai Sun, 28 Aug 2026

We thank both reviewers for their valuable comments. Our detailed responses are provided in the attached file.

Citation: https://doi.org/10.5194/egusphere-2026-2165-AC1

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

AR by Shuai Sun on behalf of the Authors (28 Aug 2026) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (28 Aug 2026) by Tim Butler

RR by Anonymous Referee #2 (28 Aug 2026)

Suggestions for revision or reasons for rejection

The authors have considered all my comments and all relevant points were addressed adequately. However, two issues arise from the revised manuscript and supplementary data:

1. Line 134 and 135: The numbers for the yearly prior emissions apparently refer to 2019. This should be stated in the text.

2. The revised supplementary table S1 contains uncertainties as requested. But for some countries, the (absolute) posterior uncertainties are larger than the prior uncertainties. Such an increase in uncertainties is also visible in the revised Figures 7a, 9 and 10. The method section suggests that posterior and prior uncertainties are defined by Ŝ and Sa, which are related by Eq. (3). The projection to countries is described in Eqs. (5) and (6). Following these equation and the assumption that the matrices S0 and Sa are real-symmetric and positive definite, the posterior uncertainties must always be smaller or equal to the prior uncertainties. Thus, there must be some inconsistency that should be clarified.

The revised Figures 7b and 12 highlight an issue that I overlooked in the first round of review. Since this is not a new issue of the revised manuscript, I do not request any changes. But I want to inform the authors why I think the uncertainty analysis is no optimal:
The prior and posterior uncertainties on the trends are apparently based on the deviation of the emission time series from a linear fit. This method is adequate if fluctuations in a (long) time series provide sufficient information on the uncertainties. But the prior emissions in this work contain very little temporal fluctuations by construction. This does not mean that the trends are perfectly known a priori. For a more realistic uncertainty estimate, one could consider the uncertainties on prior and posterior emissions. A linear fit that takes into account those uncertainties will lead to considerably larger uncertainties on the trend, especially for the prior.

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RR by Anonymous Referee #1 (08 Sep 2026)

ED: Publish subject to minor revisions (review by editor) (21 Sep 2026) by Tim Butler

AR by Shuai Sun on behalf of the Authors (23 Sep 2026) Author's response Author's tracked changes Manuscript

ED: Publish as is (23 Sep 2026) by Tim Butler

AR by Shuai Sun on behalf of the Authors (28 Sep 2026) Manuscript

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Short summary

This study estimates methane emissions across Europe from 2019 to 2023 using atmospheric methane measurements from satellites and ground stations to improve understanding of emission sources. We find that total emissions are slightly higher than official reports, mainly due to livestock and waste, while emissions from fossil fuel production are lower in some regions. These results show that atmospheric measurements can improve independent verification of emissions and support climate policy.