African volcanic emissions influencing atmospheric aerosols over  the Amazon rain forest

Saturno, Jorge; Ditas, Florian; Penning de Vries, Marloes; Holanda, Bruna A.; Pöhlker, Mira L.; Carbone, Samara; Walter, David; Bobrowski, Nicole; Brito, Joel; Chi, Xuguang; Gutmann, Alexandra; Hrabe de Angelis, Isabella; Machado, Luiz A. T.; Moran-Zuloaga, Daniel; Rüdiger, Julian; Schneider, Johannes; Schulz, Christiane; Wang, Qiaoqiao; Wendisch, Manfred; Artaxo, Paulo; Wagner, Thomas; Pöschl, Ulrich; Andreae, Meinrat O.; Pöhlker, Christopher

doi:https://doi.org/10.5194/acp-18-10391-2018

Articles | Volume 18, issue 14

https://doi.org/10.5194/acp-18-10391-2018

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

Special issue:

https://doi.org/10.5194/acp-18-10391-2018

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

Articles | Volume 18, issue 14

Research article

|

23 Jul 2018

Research article |

| 23 Jul 2018

African volcanic emissions influencing atmospheric aerosols over the Amazon rain forest

Jorge Saturno, Florian Ditas, Marloes Penning de Vries, Bruna A. Holanda, Mira L. Pöhlker, Samara Carbone, David Walter, Nicole Bobrowski, Joel Brito, Xuguang Chi, Alexandra Gutmann, Isabella Hrabe de Angelis, Luiz A. T. Machado, Daniel Moran-Zuloaga, Julian Rüdiger, Johannes Schneider, Christiane Schulz, Qiaoqiao Wang, Manfred Wendisch, Paulo Artaxo, Thomas Wagner, Ulrich Pöschl, Meinrat O. Andreae, and Christopher Pöhlker

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Final revised paper (published on 23 Jul 2018)
Supplement to the final revised paper
Preprint (discussion started on 15 Dec 2017)
Supplement to the preprint

Interactive discussion

Status: closed

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

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RC1: 'Interesting dataset but the main conclusions need to be better supported', Evgenia Ilyinskaya, 16 Jan 2018
- AC1: 'Response to RC1', Jorge Saturno, 19 Apr 2018
RC2: 'Review of Saturno et al.', Anonymous Referee #2, 23 Jan 2018
- AC2: 'Response to RC2', Jorge Saturno, 19 Apr 2018

Peer-review completion

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

AR by Jorge Saturno on behalf of the Authors (19 Apr 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 Apr 2018) by Ken Carslaw

RR by Anonymous Referee #2 (14 May 2018)

Suggestions for revision or reasons for rejection

Given the detailed answer of the authors and their present state of knowledge, anomalies in aerosol properties over the Amazon rain forest may originate from African volcanoes of the DRC but it seems still difficult at this stage to discard other potential sources and/or a mix of various sources.

At least, biomass burning fire sources, including fires from Africa, may not be easily rejected when we look at the new figure displaying MODIS fire thermal anomalies provided by the authors in their answer to reviewers.This time series of maps indicates the presence of huge and widespread fires taking place in the Nyiragongo/Nyamuragira volcanic region, but also on a much broader area of Africa, concurrently with volcanic sulfur-rich emissions.

In this respect, a specific paragraph in the discussion part of the paper should be dedicated to a discussion of this alternative biomass burning source of sulfate aerosols. This section should include the time series of MODIS thermal anomaly maps.

A short but not subsidiary question on the new Fig. 2:
The box and whisker plot would suggest that the event of interest has a signature distinct from BB and FF combustion sources. However, this figure lacks information on how it has been built:

1- How many samples are used to calculate box and whisker plots for sulfate mass concentration and SSA for the second case of biomass burning? Is it statistically comparable to the 21-30 Sept 2014 event of interest?
2- What covers the biomass burning case, does it also include biomass burning events from Africa or other countries?
3- As it is, we can just see that most values of the biomass burning case overlap with data from the 21-30 Sept 2014.

Apart from this point, the authors have well answered to most of the questions raised by reviewers and their paper could then be published in ACP.

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RR by Evgenia Ilyinskaya (16 May 2018)

ED: Publish subject to minor revisions (review by editor) (24 May 2018) by Ken Carslaw

AR by Jorge Saturno on behalf of the Authors (13 Jun 2018) Author's response Manuscript

ED: Publish as is (22 Jun 2018) by Ken Carslaw

AR by Jorge Saturno on behalf of the Authors (02 Jul 2018)

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Short summary

This study uses satellite observations to track volcanic emissions in eastern Congo and their subsequent transport across the Atlantic Ocean into the Amazon Basin. Aircraft and ground-based observations are used to characterize the influence of volcanogenic aerosol on the chemical and microphysical properties of Amazonian aerosols. Further, this work is an illustrative example of the conditions and dynamics driving the transatlantic transport of African emissions to South America.