Emission or atmospheric processes? An attempt to attribute the source of large bias of aerosols in eastern China simulated by global climate models

Fan, Tianyi; Liu, Xiaohong; Ma, Po-Lun; Zhang, Qiang; Li, Zhanqing; Jiang, Yiquan; Zhang, Fang; Zhao, Chuanfeng; Yang, Xin; Wu, Fang; Wang, Yuying

doi:https://doi.org/10.5194/acp-18-1395-2018

Articles | Volume 18, issue 2

https://doi.org/10.5194/acp-18-1395-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue:

Regional transport and transformation of air pollution in...

https://doi.org/10.5194/acp-18-1395-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 18, issue 2

Research article

|

01 Feb 2018

Research article |

| 01 Feb 2018

Emission or atmospheric processes? An attempt to attribute the source of large bias of aerosols in eastern China simulated by global climate models

Tianyi Fan, Xiaohong Liu, Po-Lun Ma, Qiang Zhang, Zhanqing Li, Yiquan Jiang, Fang Zhang, Chuanfeng Zhao, Xin Yang, Fang Wu, and Yuying Wang

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Final revised paper (published on 01 Feb 2018)
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Preprint (discussion started on 28 Sep 2016)
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Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Comments to acp-2016-802', Anonymous Referee #1, 20 Oct 2016
RC2: 'Interactive comment on acp-2016-802', Anonymous Referee #2, 13 Dec 2016
- AC2: 'Responds to Referee #2’s comments', Fan Tianyi, 26 Feb 2017
  - AC3: 'corrected version', Fan Tianyi, 09 Mar 2017
AC1: 'Authors' comments on the emission uncertainty, seasonal cycle of sulfate, and etc.', Fan Tianyi, 26 Feb 2017

Peer-review completion

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

AR by Tianyi Fan on behalf of the Authors (12 Mar 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (20 Mar 2017) by Tong Zhu

RR by Anonymous Referee #1 (27 Mar 2017)

RR by Anonymous Referee #3 (02 Apr 2017)

Suggestions for revision or reasons for rejection

I do not recommend this manuscript be published based on the following reasons:
(1) I cannot find any significant scientific findings except the authors used a new emission inventory, MEIC.
(2) The authors found the AOD simulations were improved by using MEIC, however, they also declared “MEIC emission leads to a better agreement with the observed surface concentrations of primary aerosols (i.e., primary organic carbon and black carbon) than the AR5 emission, while the seasonal variation of secondary aerosols (i.e., sulfate and secondary organic aerosol) depends less on the emission”. The conclusions were not convincing, even as the authors stated in Section “3.1 Comparing MEIC and AR5 emission inventories”, the emissions in eastern China had changed a lot, but could not be reflected by their secondary aerosol simulations. It is contradictory. The authors should analysis the modeling results in more detail to find reasonable explanations.
(3) The secondary aerosols (depends strongly on the emission changings as in eastern China) are very important for the ADRE calculations, especially the authors used internally mixed state within each mode. But we cannot find any modeling improvements or related explanations in the manuscript.
(4) The title is not “Impact of a new emission inventory on CAM5 simulations of aerosols and aerosol radiative effects in eastern China”. Firstly, the ADRE is through the whole text, we cannot find semi-direct effects, “aerosol radiative effects” is not appropriate for the title. Secondly, I agree the other two reviewers’ comments, no improvements for secondary aerosol formation were added in the simulations and the readers cannot find the secondary simulations be better than previous researches, “simulations of aerosols” is also not appropriate in the title.
(5) The structure was not well, Section “3.1 Comparing MEIC and AR5 emission inventories” are not the authors’ research results, others who are involved in simulations or emissions could get it.

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ED: Reject (24 Apr 2017) by Tong Zhu

ED: Reconsider after major revisions (03 Jul 2017) by Tong Zhu

AR by Tianyi Fan on behalf of the Authors (05 Jul 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (24 Jul 2017) by Tong Zhu

RR by Anonymous Referee #4 (08 Aug 2017)

Suggestions for revision or reasons for rejection

Review of Fan et al. (acp-2016-802)

In this study the authors examined the impact of a new emission inventory on aerosols and their radiative effects in eastern China using a global aerosol-climate model. Many global models suffer a low bias in simulating aerosols over the heavily polluted East Asia, and it is well known that aerosol emissions over there are highly uncertain. With the new technology-based multi-resolution emissions inventory for China, they found that low biases in AOD simulated with the widely used AR5 emissions are reduced and seasonal variations in primary aerosols are also improved, as evaluated against satellite retrievals and surface observations. These improvements in aerosols are found to have a significant impact on the regional aerosol direct radiative forcing. I have also read the comments on a previous version of the manuscript from two reviewers and the authors’ responses. I agree with the reviewers on some of the good points and the “fair” scientific significance. However, I believe the authors have done a good job in addressing the comments and revising the manuscript, which has now become publishable. In particular, the new MEIC emissions files prepared for the CAM5 model, if made available to the community, would be a very useful contribution. Below I offer a few comments for the authors to consider before the final publication.

Comments:

1) How does the MEIC emission inventory compare to the newly released CEDS (Community Emission Data System; Hoesly et al., 2017) for China? The CEDS dataset has been used in CAM5 by Yang et al. (2017) to study black carbon and its direct radiative forcing in China. I understand that the CEDS dataset probably wasn’t available when this manuscript was first submitted, but since it is now released to the community and intended for use in CMIP6 simulations, the authors should include a discussion on this.
2) It is not very clear about the simulations performed in this study and results shown in some of the figures. Please clarify in section 2.1 as well as all of the relevant figure captions, including the time period of observations used for model evaluation. Why is a linear interpolation between year 2008 and 2010 needed to obtained MEIC emissions in 2009 (lines 163-164)? Please clarify.
3) It is good to be precise, but I don’t think it is really useful to keep so many significant figures (e.g., two digits after the decimal point) in some of the numbers in the results section, especially, for those numbers of percentage and/or with trailing zeros.
4) Supposedly, the AR5 SO2 and primary aerosol emissions in Figure 3 are for anthropogenic sectors only (section 2.2), so there are no seasonal variations in SO2 and BC, but why is there variation in POM? Please clarify.

Technical corrections:

Line 16: energy-statistics?
Line 67: Is it “multi-scale” or “multi-resolution” for MEIC?
Line 123: Did you actually change the model code to take the MEIC emissions? Or just prepare the emissions as input files for the model?
Line 199: Change “presents” to “presence”
Line 343: Please make sure if R squared in Figure 8 is correlation coefficient.
Figure 16 caption: Remove “change of”.

References:

Hoesly, R. M., Smith, S. J., Feng, L., Klimont, Z., Janssens-Maenhout, G., Pitkanen, T., Seibert, J. J., Vu, L., Andres, R. J., Bolt, R. M., Bond, T. C., Dawidowski, L., Kholod, N., Kurokawa, J.-I., Li, M., Liu, L., Lu, Z., Moura, M. C. P., O'Rourke, P. R., and Zhang, Q.: Historical (1750–2014) anthropogenic emissions of reactive gases and aerosols from the Community Emission Data System (CEDS), Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2017-43, in review, 2017.

Yang, Y., Wang, H., Smith, S. J., Ma, P.-L., and Rasch, P. J.: Source attribution of black carbon and its direct radiative forcing in China, Atmos. Chem. Phys., 17, 4319-4336, https://doi.org/10.5194/acp-17-4319-2017, 2017.

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RR by Anonymous Referee #5 (21 Aug 2017)

ED: Reconsider after major revisions (06 Sep 2017) by Tong Zhu

AR by Tianyi Fan on behalf of the Authors (17 Oct 2017)

ED: Referee Nomination & Report Request started (31 Oct 2017) by Tong Zhu

RR by Anonymous Referee #5 (06 Dec 2017)

ED: Publish subject to minor revisions (review by editor) (07 Dec 2017) by Tong Zhu

AR by Tianyi Fan on behalf of the Authors (17 Dec 2017) Author's response Manuscript

ED: Publish as is (26 Dec 2017) by Tong Zhu

AR by Tianyi Fan on behalf of the Authors (28 Dec 2017)

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Short summary

We found that 22–28 % of the low AOD bias in eastern China simulated by the Community Atmosphere Model version 5 can be improved by using a new emission inventory. The concentrations of primary aerosols are closely related to the emission, while the seasonal variations of secondary aerosols depend more on atmospheric processes. This study highlights the importance of improving both the emission and atmospheric processes in modeling the atmospheric aerosols and their radiative effects.