Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China

Li, Zhujie; Tan, Haobo; Zheng, Jun; Liu, Li; Qin, Yiming; Wang, Nan; Li, Fei; Li, Yongjie; Cai, Mingfu; Ma, Yan; Chan, Chak K.

doi:https://doi.org/10.5194/acp-19-11669-2019

Articles | Volume 19, issue 18

https://doi.org/10.5194/acp-19-11669-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Multiphase chemistry of secondary aerosol formation under...

https://doi.org/10.5194/acp-19-11669-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 18

Research article

|

19 Sep 2019

Research article |

| 19 Sep 2019

Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China

Zhujie Li, Haobo Tan, Jun Zheng, Li Liu, Yiming Qin, Nan Wang, Fei Li, Yongjie Li, Mingfu Cai, Yan Ma, and Chak K. Chan

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Final revised paper (published on 19 Sep 2019)
Supplement to the final revised paper
Preprint (discussion started on 04 Jan 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Comments on acp-2018-1331', Anonymous Referee #1, 23 Jan 2019
- AC1: 'Responses to both reviewers (please see attached PDF file for details)', Jun Zheng, 11 Apr 2019
RC2: 'Review of "Light absorption property and potential source of particulate brown carbon in the Pearl River Delta region of China" by Li et al.', Anonymous Referee #2, 04 Feb 2019
- AC1: 'Responses to both reviewers (please see attached PDF file for details)', Jun Zheng, 11 Apr 2019

Peer-review completion

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

AR by Jun Zheng on behalf of the Authors (11 Apr 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (17 Apr 2019) by Jingkun Jiang

RR by Anonymous Referee #1 (07 May 2019)

RR by Anonymous Referee #3 (13 May 2019)

Suggestions for revision or reasons for rejection

This manuscript has been improved since last version, however the data analysis I think is still a bit superficial, at least the figures in terms of supporting your key conclusions, are quite scattered without focus.

Major comments:
The authors have made a lot of efforts in addressing how the BC core has been calculated, however there is no plot to show this at all. It is mentioned that previous VTDMA measurements were conducted, would you like to show these results? would you like to show the BC core size distribution etc…

There are quite a few fundamental plots missing:

Time series of AAE measured by AE33.
Time series of assumed/derived BC core size.
A total scattering, SSA.
An analysis of air mass origins to indicate the possible source influences on high loadings of OC.

A large section of texts and analysis to demonstrate that AAE could be subject to uncertainties resulting from core size, RI, Df etc. however there is no plot really showing that, not a model-only sensitivity plot, but some plots really showing your data. The model-only plot could be in supplement, but merge Fig. 3 and Fig. 4 by incorporating your data.

I don’t quite like Fig.3, would you like to show a time series of predicted AAE to indicate at which period the uncertainty could be large.

In Fig. 8, there is no point to correlate BrC absorption with everything, again I would like to see a comprehensive time series to show the correlation at different periods.

Have you got at least levoglucosan data, a K+/levoglucosan may indicate possible different sources.

There are many duplications between Fig. 7 and Fig. 9, would you merge some of the information and present only the important message neatly?

It is unnecessary to show all of the sensitivity analysis in Fig. 10.

Suggestions:
Regarding how far this paper could go, I think at least one useful key message should be delivered, not just simply report how much BrC could occupy in shorter wavelength. I would think you could point out at this southern coastal site during this season, how much AAE could reach, what the general background look like, how important could the BrC there compared to other places over China. Are those BrC from fire or just anthropogenic?

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ED: Reconsider after major revisions (13 May 2019) by Jingkun Jiang

AR by Anna Wenzel on behalf of the Authors (23 Jul 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (23 Jul 2019) by Jingkun Jiang

RR by Anonymous Referee #3 (07 Aug 2019)

RR by Anonymous Referee #1 (07 Aug 2019)

ED: Publish subject to minor revisions (review by editor) (08 Aug 2019) by Jingkun Jiang

AR by Jun Zheng on behalf of the Authors (15 Aug 2019) Author's response Manuscript

ED: Publish as is (18 Aug 2019) by Jingkun Jiang

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Short summary

Comprehensive field measurements were conducted to investigate aerosol compositions, optical properties, source origins, and radiative forcing effects in Guangzhou. Particulate brown carbon (BrC) light absorption was differentiated from that of black carbon. BrC was mostly due to primary emissions, such as straw burning, rather than secondary formation. BrC may cause ∼2.3 W m⁻² radiative forcing at the top of the atmosphere and contribute to ∼15.8 % of the aerosol warming effect.