Articles | Volume 26, issue 14
https://doi.org/10.5194/acp-26-10455-2026
© Author(s) 2026. This work is distributed under the Creative Commons Attribution 4.0 License.
Applying satellite observations to improve bottom-up national emission inventories for methane: application to Colombia
Download
- Final revised paper (published on 27 Jul 2026)
- Supplement to the final revised paper
- Preprint (discussion started on 09 Feb 2026)
- Supplement to the preprint
Interactive discussion
Status: closed
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor
| : Report abuse
- RC1: 'Comment on egusphere-2025-5478', Anonymous Referee #1, 31 Mar 2026
- RC2: 'Comment on egusphere-2025-5478', Anonymous Referee #2, 15 Apr 2026
- AC1: 'Comment on egusphere-2025-5478', Sarah Hancock, 28 Apr 2026
Peer review completion
AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
AR by Sarah Hancock on behalf of the Authors (28 Apr 2026)
Author's response
Author's tracked changes
Manuscript
ED: Referee Nomination & Report Request started (03 May 2026) by Jayanarayanan Kuttippurath
RR by Anonymous Referee #2 (17 May 2026)
RR by Anonymous Referee #1 (20 May 2026)
ED: Reconsider after major revisions (28 May 2026) by Jayanarayanan Kuttippurath
AR by Sarah Hancock on behalf of the Authors (18 Jun 2026)
Author's response
Author's tracked changes
Manuscript
ED: Referee Nomination & Report Request started (21 Jun 2026) by Jayanarayanan Kuttippurath
RR by Anonymous Referee #1 (22 Jun 2026)
ED: Publish as is (06 Jul 2026) by Jayanarayanan Kuttippurath
AR by Sarah Hancock on behalf of the Authors (08 Jul 2026)
Manuscript
This manuscripts uses TROPOMI and GOSAT observations to constrain methane emissions in Colombia at high resolution for 2023. The authors develop a high-resolution gridded bottom-up inventory of methane emissions. Using GEOS-Chem as a forward model, they solve an analytical Bayesian inversion to update the bottom-up inventory. The main value is the development of a high-resolution gridded emissions inventory constrained by satellite observations that yield specific suggestions for improving bottom-up estimation methods. I find the work to be novel, well-written, a valuable addition to the field, and suitable for ACP. However, I have major questions regarding validation of posterior emissions and robustness of the sector attribution.
Major comments:
1. L341-342: This argument makes sense. However, I do not believe the posterior error variance is shown in the main text or SI. Could the authors provide further justification of this claim by comparing posterior error variance at each grid cell to the variance of the inversion ensemble, perhaps in the supplement? Additionally, it would be useful to see a comparison of the prior and posterior error variance at each grid cell.
2. The posterior emissions would be more compelling if they were independently validated. To my understanding, only in-sample validation has been shown (Figure 7). Could the authors show that the posterior emissions improve simulation of TROPOMI and GOSAT observations that are held out of the inversion? Either in 2023 or in a different year?
3. Figure 6: it looks like the largest changes to the emissions occurred in regions coincident with observations (Figure 7). Could the authors show a map of the diagonal elements of the averaging kernel (i.e., Aii) or DOFS averaged over regions to show where posterior emissions are constrained by observations? If there are regions that are not constrained well by the observations, can the authors discuss them? This is partially addressed with the discussion of Carbon-I (L538) but it would be clearer if this was directly shown.
4. In general, I am skeptical of the posterior sector attribution for non-point sources (wetlands, livestock, rice) in regions where these emissions are co-located (e.g., wetland emissions in the La Mojana region and Magdalena River with livestock emission in Figs. 4 and 3). The authors assume that posterior sector emissions in each grid cell are proportional to prior sector emissions. While total sector emissions errors are generally uncorrelated (Figure S2), this does not mean that finer-scale attribution is correct. High uncertainty in the spatial distribution of prior non-point source emissions will propagate to the posterior sector emissions. The following comments relate to this point:
a. The authors briefly discuss this uncertainty in L548-550. However, because this is a key assumption affecting interpretation, the sector attribution method should be made clearer in the abstract and conclusion.
b. Figure S2 shows low posterior error correlations between sectors, but this does not necessarily demonstrate that sectors are independently constrained by the observations. Could the authors provide the sector-resolved averaging kernel (i.e., WAWT) as another diagnostic to assess whether co-located sectors can be meaningfully distinguished (e.g., whether the diagonal elements are large and off-diagonal elements are small), or whether sector attribution is primarily driven by prior assumptions?
c. Can the authors provide more discussion of how the uncertainty in the distribution of the prior wetland emissions could affect posterior sector emissions? While sensitivity tests using global inventories (Figure S2) are helpful, the problem remains underdetermined, and these tests may not fully explore the uncertainty space.
d. Figure 8: Could the high posterior emissions factor in Magdalena Medio have been a misattribution of wetland emissions to livestock emissions? The GLWD + LPJ prior shows weak but notable emissions in that region. If the prior wetland emissions were biased low or too spatially concentrated, could the posterior livestock emissions be biased high?
e. It would be useful to see a map of the change in prior and posterior sector emissions to better evaluate sector attribution. This is done for the wetland emissions in the La Mojana region (Figure S4), but difference plots would be useful for the sector emissions in general.
Minor comments:
5. It would be nice to see an explicit comparison of the spatial distribution of wetland emissions from GLWD + LPJ compared to LPJ alone. e.g., a difference plot.
6. It is not clear to me how the seasonal cycle of wetland emissions is considered in the inversion. I assume that the K matrix contains this information via the time-resolved forward model? If that is the case, could the authors make that clearer?