Toward a versatile spaceborne architecture for immediate monitoring of the global methane pledge

Wang, Yuchen; Guo, Xvli; Huo, Yajie; Li, Mengying; Pan, Yuqing; Yu, Shaocai; Baklanov, Alexander; Rosenfeld, Daniel; Seinfeld, John H.; Li, Pengfei

doi:https://doi.org/10.5194/acp-23-5233-2023

Articles | Volume 23, issue 9

https://doi.org/10.5194/acp-23-5233-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-23-5233-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 9

Research article

|

10 May 2023

Research article |

| 10 May 2023

Toward a versatile spaceborne architecture for immediate monitoring of the global methane pledge

Yuchen Wang, Xvli Guo, Yajie Huo, Mengying Li, Yuqing Pan, Shaocai Yu, Alexander Baklanov, Daniel Rosenfeld, John H. Seinfeld, and Pengfei Li

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Final revised paper (published on 10 May 2023)
Supplement to the final revised paper
Preprint (discussion started on 21 Jul 2022)
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Status: closed

RC1:
'Comment on acp-2022-518', Anonymous Referee #1, 06 Jan 2023

Please see the attached PDF for my review details.

Citation: https://doi.org/10.5194/acp-2022-518-RC1
- AC1: 'Reply on RC1', Pengfei Li, 13 Feb 2023
  
  We truly appreciate all of these valuable comments and suggestions. Please see the attached PDF for our reply details.
  
  Citation: https://doi.org/10.5194/acp-2022-518-AC1
CC1:
'Comment on acp-2022-518', Pol Ribes Pleguezuelo, 18 Jan 2023
Title: A versatile spaceborne architecture for immediate monitoring of the global methane pledge

The article shows a very interesting approach to investigate the different methane emissions using available satellites (TROPOMI and PRIMA) and suggesting that a multi-tiered constellation could be implemented.

Some comments on the article of possible improvements:

Line 60 you introduce the term “super-emitters” for first time, the term should be defined better (how big/small, released methane, how spread, etc.) in contrast with hot spots and area sources. This should be tailored for the satellite swath and resolution.

Between lines 80 to 92 a review of existing and capable of detecting methane satellites is shown. However, the swath, passes, resolution, etc. is not given for all satellites. I would suggest to add a table with such information. This would help to better understand/propose a future multi-tiered constellation which could act globally.

A conclusions section with a better explanation of what number of satellites (which ones in the pipeline / resolution), and aircrafts needed to have a proper coverage would be needed. Also, would it be night monitoring important, which method or missions could be used? Atmospheric Lidars? Would the retrieval of structured atmospheric column help the analysis?

Cosmetics:
Spacing between text and references. In Line 57, 59, 136, 223, 225, 244, 312, 343, 360.

Reference in line 117, is this correct format for the current article? In contract to the one in line 145. Is it need to have same info twice?
Citation: https://doi.org/10.5194/acp-2022-518-CC1
- AC2: 'Reply on CC1', Pengfei Li, 13 Feb 2023
  
  Thank you very much for your valuable comments and suggestions. Please check the attached PDF for our reply details.
  
  Citation: https://doi.org/10.5194/acp-2022-518-AC2
RC2:
'Comment on acp-2022-518', Anonymous Referee #2, 21 Jan 2023

This paper aims at proposing a framework to utilize current space-borne methane observations to monitor regional emission hotspots and qualify super emitters. The framework combines two methods: one based on global mapping using TROPOMI and the other based on PRISMA (or other high-resolution mappings for small target areas). However, it is not clear what makes this framework different from previous studies (many are cited here), and it is suggested that the authors should clearly state the novel aspects of their method.

Additionally, the approach is only demonstrated over short periods for five small areas, and the results are well compared with previous studies. The method for identifying high-emission areas and plumes appears to be “visual inspection”, which raises questions about how this "framework" could scale to "immediate monitoring of the global methane." This is a key point that needs to be addressed for “a versatile spaceborne architecture.” Besides, the detection limit of this method and how it deals with hotspots from natural sources or other anthropogenic sectors other than oil and gas (landfill, agriculture) should be better illustrated before the paper is considered for publication.

Technical Points:

The title and the abstract are a bit perplexing. The multi-tiered reads mostly two-tiered. I think clarifying these basic points would be helpful for the reader. In the abstract, it would be nice if the authors could briefly describe what this “versatile spaceborne architecture" is, and what data it is based on using what methods. At the moment, one needs to read the paper to a large extent to get some idea of “this framework”. The paper could also benefit from adjusting the scope of the text to the results presented here.

Line 51: Ocko et al., 2021 only refers to the anthropogenic methane sources. It is important to state this precisely, not to confuse it with the large portion of methane emissions from natural sources. The current text might be misleading.

Line 55, line 59, and many other places: please check references.

Fig. 1 How is “colocation” defined? Using what kind of criteria?

Fig. 2 What temporal periods are considered here to calculate the percentage?

Fig. 4 How to reconcile PRISMA and TROPOMI results? It seems there are still differences in the order of magnitude.

Citation: https://doi.org/10.5194/acp-2022-518-RC2
- AC3: 'Reply on RC2', Pengfei Li, 13 Feb 2023
  
  Thank you very much for your valuable comments and suggestions. Please check the attached PDF for our reply details.
  
  Citation: https://doi.org/10.5194/acp-2022-518-AC3

Peer review completion

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

AR by Pengfei Li on behalf of the Authors (13 Feb 2023) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (14 Feb 2023) by Eduardo Landulfo

RR by Anonymous Referee #1 (14 Mar 2023)

ED: Publish subject to minor revisions (review by editor) (24 Mar 2023) by Eduardo Landulfo

AR by Pengfei Li on behalf of the Authors (28 Mar 2023) Author's response Author's tracked changes Manuscript

ED: Publish as is (18 Apr 2023) by Eduardo Landulfo

AR by Pengfei Li on behalf of the Authors (19 Apr 2023) Manuscript

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Short summary

Substantial advances have been made in recent years toward detecting and quantifying methane super-emitters from space. However, such advances have rarely been expanded to measure the global methane pledge because large-scale swaths and high-resolution sampling have not been coordinated. Here we present a versatile spaceborne architecture that can juggle planet-scale and plant-level methane retrievals, challenge official emission reports, and remain relevant for stereoscopic measurements.

Toward a versatile spaceborne architecture for immediate monitoring of the global methane pledge

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