Biomass burning emission disturbances of isoprene oxidation  in a tropical forest

Santos, Fernando; Longo, Karla; Guenther, Alex; Kim, Saewung; Gu, Dasa; Oram, Dave; Forster, Grant; Lee, James; Hopkins, James; Brito, Joel; Freitas, Saulo

doi:https://doi.org/10.5194/acp-18-12715-2018

Articles | Volume 18, issue 17

https://doi.org/10.5194/acp-18-12715-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

South AMerican Biomass Burning Analysis (SAMBBA)

https://doi.org/10.5194/acp-18-12715-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 17

Research article

|

04 Sep 2018

Research article |

| 04 Sep 2018

Biomass burning emission disturbances of isoprene oxidation in a tropical forest

Fernando Santos, Karla Longo, Alex Guenther, Saewung Kim, Dasa Gu, Dave Oram, Grant Forster, James Lee, James Hopkins, Joel Brito, and Saulo Freitas

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Final revised paper (published on 04 Sep 2018)
Supplement to the final revised paper
Preprint (discussion started on 22 Dec 2017)
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Interactive discussion

Status: closed

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

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RC1: 'Reviewer comment: Biomass burning emissions disturbances on the isoprene oxidation in a tropical forest', Anonymous Referee #1, 24 Feb 2018
- AC1: 'Author comments', Fernando Santos, 14 May 2018
RC2: 'Review of Santos et al.', Anonymous Referee #2, 03 Mar 2018
- AC2: 'Author comments', Fernando Santos, 14 May 2018
RC3: 'Review of Santos et a, ACP ...1083', Anonymous Referee #3, 14 Mar 2018
- AC3: 'Author comments', Fernando Santos, 14 May 2018

Peer-review completion

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

AR by Fernando Santos on behalf of the Authors (25 May 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (29 May 2018) by Meinrat O. Andreae

RR by Anonymous Referee #2 (11 Jun 2018)

RR by Anonymous Referee #1 (11 Jun 2018)

Suggestions for revision or reasons for rejection

The authors have corrected and updated the manuscript as recommended by the reviewers, and I have little else to comment on. The added discussion of the uncertainties and potential sources of error in their method, while short, is a good addition to the paper. Some minor editorial issues remain, detailed below; the line numbers are partially cut off in every pdf I can find of the new document, so I'll just write page numbers and try to make myself clear:

p2, first paragraph of introduction: "a natural mechanism to balance the VOCs emitted and its degradation" - 'its' should be 'their'

p3, ~8 lines from the bottom: "More recently, significant advances have been made with organic peroxy radicals (RO2) produced as intermediates of atmospheric photochemistry, showing the importance of the subsequent reaction pathway to isoprene chemistry. Its accurate understanding..." - it's still unclear what this is trying to say about isoprene oxidation in the context of this paper. The subsequent reaction pathways of RO2 radicals are by definition important to isoprene chemistry, since basically all isoprene goes through peroxy radical pathways. What have the "significant advances" changed about that understanding that is relevant to the work done in this paper? What is the "Its" in the next sentence ("Its accurate understanding...")?

p5, ~ middle of the page, "(1) the quadrupole detector cannot distinguish between the isobaric molecules MVK and MACR, and its decomposition interferer ISOPOOH, so it reports the data at m/z 71 as the sum of 3 isomers, even though it was only calibrated for MVK+MACR" - I think it's worth noting here, as you wrote in your response to the reviewers, that while the conversion of ISOPOOH was estimated to be above 70%, it is likely sensitive to instrumental conditions, and therefore may introduce another source of uncertainty here.

p12, ~3 lines from top: "The results shown the isoprene oxidation reaction is also enhanced" - 'shown' should be 'show', or 'show that'

p13, in the newly added paragraph (near the top): "the reaction of isoprene with peroxy radicals (HO2) as an alternative pathway to OH production" - I assume this means the reaction of isoprene-derived-peroxy-radicals with HO2, not the reaction of isoprene itself with peroxy radicals?

p14, last paragraph of section 3.3: "In this study, we modified a method to estimated OH concentration values" - 'estimated' should be 'estimate'; further down the paragraph, in the sentence "We also evaluated the predominance of SAMBBA data between 11:00 am–2:00 pm, especially for BG and FP groups, may alter the distribution of [MVK+MACR+ISOPOOH]/[isoprene] ratio along the diurnal cycle, and consequently modify the OH estimated.", I think you need 'which' before 'may alter.

Finally, that last paragraph of Section 3.3 seems better suited to be the first paragraph in the Final Remarks section, as it provides a nice summary of what you've done and the potential uncertainties and limitations of the method.

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RR by Anonymous Referee #3 (12 Jun 2018)

ED: Publish subject to technical corrections (20 Jun 2018) by Meinrat O. Andreae

AR by Fernando Santos on behalf of the Authors (03 Jul 2018) Author's response Manuscript

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Short summary

We investigated the impact of biomass burning on the chemical composition of trace gases in the Amazon. The findings corroborate the influence of biomass burning activity not only on direct emissions of particulate matter but also on the oxidative capacity to produce secondary organic aerosol. The scientists plan to use this information to improve the numerical model simulation with a better representativeness of the chemical processes, which can impact on global climate prediction.