A 15-year record of CO emissions constrained by MOPITT CO observations

Jiang, Zhe; Worden, John R.; Worden, Helen; Deeter, Merritt; Jones, Dylan B. A.; Arellano, Avelino F.; Henze, Daven K.

doi:https://doi.org/10.5194/acp-17-4565-2017

Articles | Volume 17, issue 7

https://doi.org/10.5194/acp-17-4565-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-17-4565-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 17, issue 7

Research article

|

06 Apr 2017

Research article |

| 06 Apr 2017

A 15-year record of CO emissions constrained by MOPITT CO observations

Zhe Jiang, John R. Worden, Helen Worden, Merritt Deeter, Dylan B. A. Jones, Avelino F. Arellano, and Daven K. Henze

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Final revised paper (published on 06 Apr 2017)
Supplement to the final revised paper
Preprint (discussion started on 17 Oct 2016)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

- Printer-friendly version

- Supplement

RC1: 'Review', Anonymous Referee #1, 14 Dec 2016
- AC1: 'reply to comments', Zhe Jiang, 17 Jan 2017
RC2: 'RC2: 'Review', Anonymous Referee #2', Anonymous Referee #2, 06 Jan 2017
- AC2: 'reply to comments', Zhe Jiang, 17 Jan 2017

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Zhe Jiang on behalf of the Authors (17 Jan 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (02 Feb 2017) by Jayanarayanan Kuttippurath

RR by Anonymous Referee #1 (02 Feb 2017)

Suggestions for revision or reasons for rejection

I still recommend major revision, since some hard points have been left untouched. Pending issues are as follows. Q numbers refer to the reply.

Q4: the authors have inserted a brief discussion about the seasonal cycle of the bias in the vertical, but the key question is about its interannual variability and it remains untouched.

Q5: the authors say that the question is very good, but have not modified their text. They should show their “results [that] show that the difference in the scaling factors is small” to justify their surprising set-up. Sentence “Due to lack of meaningful information about the systematic errors, we assume a uniform observation error of 20% without spatial correlation” in the paper still confuses covariances and averages.

l. 210: “Without consideration of systematic errors, the a posteriori error covariance matrix is the inverse…”: a covariance matrix remains the same whether or not we consider systematic errors. More generally, changes in the text would deserve better reading and language-checking by the authors.

l. 249: “Jiang et al. (2015b) indicated that the results of regional inversions are more reliable…” => the statement is too general and should be replaced by “Jiang et al. (2015b) indicated that their regional inversion results were more reliable…”

Q9: so the authors assimilate the same data twice in their system! This is quite shocking, in particular after their praise to their approach. For most data assimilation experts, this would be a show-stopper. The authors need to specifically discuss this point in their paper and find a way to show that double-counting here does not matter.

Q10: this discussion should be reflected in the paper.

Q17: the authors should develop their argument “The influence of correlation of these three levels should be small”.

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RR by Anonymous Referee #2 (28 Feb 2017)

ED: Reconsider after major revisions (01 Mar 2017) by Jayanarayanan Kuttippurath

AR by Zhe Jiang on behalf of the Authors (11 Mar 2017) Author's response Manuscript

ED: Publish subject to technical corrections (19 Mar 2017) by Jayanarayanan Kuttippurath

Dear Authors,

Thank you for submitting the revised version. The revision has definitely helped to
improve the content of the paper.

Although you have revised your manuscript in accordance with the referee reports,
I would also request you to consider the following suggestions before you submit
it for the publication.

Line 37 and throughout the article: Please use hyphen instead of “minus” sign
Line 38: 0.2% / year?
Line 41: “which are the primary factors contributing to the uncertainties”?
Line 45: “and” unchanged
Line 75: negative trend of what?
Line 85—90: Please split the sentence. Very difficult to understand now.
Line 90: delete “as a function of latitude”
Line 104: MOPITT CO data?
Line 128: write the complete form of TIR and NIR
Line 136-137: to make it more comparable, as the vertical resolution of aircraft measurements are very high?
Line 135: you can delete “here”
Line 152: The remaining bias
Line 179: September—November
Line 227: It is better to start another sentence with “. However, ….”
Line 279: “drifts in satellite measurements, and sparse”
Line 311: “satellite retrievals” not instrument
Line 329: “error in the modeled convection for this region”
Line 345: what is WDCGG?
Line 377: “increasing trend of ” or “positive trend of "
Line 426: “, which show”
Line 455: How can the variability trigger bias drift?
Line 481: “…..somewhat worse”. Please rephrase it.
Line 486: “As our a posteriori…”
Line 521—522: This sounds that the model transport and chemistry make the errors. I thought the inaccuracies in representing these processes in the model make/induce the errors/ uncertainties.

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Short summary

We constrain the long-term variation in global CO emissions for 2001–2015. Our results confirm that the decreasing trend of tropospheric CO in the Northern Hemisphere is due to decreasing CO emissions from anthropogenic and biomass burning sources. In particular, we find decreasing CO emissions from the United States and China in the past 15 years, unchanged anthropogenic CO emissions from Europe since 2008, and likely a positive trend from India and southeast Asia.