Aerosol as a potential factor to control the increasing torrential rain events in urban areas over the last decades

Lee, Seoung Soo; Kim, Byung-Gon; Li, Zhanqing; Choi, Yong-Sang; Jung, Chang-Hoon; Um, Junshik; Mok, Jungbin; Seo, Kyong-Hwan

doi:https://doi.org/10.5194/acp-18-12531-2018

Articles | Volume 18, issue 16

https://doi.org/10.5194/acp-18-12531-2018

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

https://doi.org/10.5194/acp-18-12531-2018

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

Articles | Volume 18, issue 16

Research article

|

29 Aug 2018

Research article |

| 29 Aug 2018

Aerosol as a potential factor to control the increasing torrential rain events in urban areas over the last decades

Seoung Soo Lee, Byung-Gon Kim, Zhanqing Li, Yong-Sang Choi, Chang-Hoon Jung, Junshik Um, Jungbin Mok, and Kyong-Hwan Seo

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Final revised paper (published on 29 Aug 2018)
Preprint (discussion started on 20 Feb 2018)

Interactive discussion

Status: closed

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

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RC1: 'Review of “Aerosol as a potential factor to control the increasing torrential rain events in urban areas over the last decades” by Seoung Soo Lee et al.', Anonymous Referee #1, 26 Mar 2018
- AC2: 'Authors' responses to the comments by the reviewer 1', Seoung Soo Lee, 28 May 2018
RC2: 'Review of “Aerosol as a potential factor to control the increasing torrential rain events in urban areas over the last decades” submitted to ACP for publication by Lee et al.', Anonymous Referee #2, 01 Apr 2018
- AC3: 'Authors' responses to the comments by the reviewer 2', Seoung Soo Lee, 28 May 2018
AC1: 'Authors' responses to the comments by the reviewers', Seoung Soo Lee, 28 May 2018

Peer-review completion

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

AR by Seoung Soo Lee on behalf of the Authors (28 May 2018) Manuscript

ED: Referee Nomination & Report Request started (29 May 2018) by Johannes Quaas

RR by Anonymous Referee #2 (16 Jun 2018)

Suggestions for revision or reasons for rejection

The authors have addressed my previous comments. But based on the Authors’ responses, I have the following further comments,
1. The domain size for domain 3 (inner most domain) is only 200kmX180 km, which is not a good configuration for MCS simulation. By definition, MCS at least covers more than 100 km raining region in one dimension with a fast-moving speed. So, to get the lifecycle of MCSs, you need a much larger domain than this. In addition, MCS has its unique dynamics (it is different from thermal convection) and how much of the aerosols can be entrained into the system is always a concern. The analysis is also not connected with MCS dynamics such as the front-to-real flow and real inflow. Maybe the system was not a MCS? I think it is better not to call it a MCS to avoid confusion.
2. Based on what the authors clarified now, they did not really create an aerosol module. It is actually just an “aerosol preprocessor”. So it is more appropriate to call it “aerosol preprocessor”.
3. Even if the aerosol composition is not mainly black carbon or brown carbon, for polluted city like Seoul, AOD should be high and it would scatter a lot of solar radiation and cause surface cooling. I would suggest to add a plot for AOD. In the text, it is necessary to be clear that aerosol radiation interaction is not considered in this study and also discuss the uncertainty that this effect may cause such as the cooling at the surface would reduce the CAPE for convection.
4. The 1 micro aerosol particle is already in coarse mode. Accumulation mode peaks usually at 100-200 nm. It is even important to get the Aitken mode right for strong convection. With PM10, uncertainties in both accumulation and Aitken modes would be very large. Based on the SD plot in Figure 3, smaller particles (Aitken model) aerosols are dominant in number concentrations. Did those small particles get activated? What is the total aerosol number (should be provided for each case) at low-level and what size of the aerosols can be activated? A recent study (Fan et al. 2018, Science) showed that very small particles from urban plume can be activated and enhance condensation heating significantly. This would enhance the convective intensity and precipitation rates at the convective region, both of which can lead to strong downdrafts as well. So the stronger downdrafts might not just be due to the larger evaporative cooling as the authors claimed. I would suggest looking at this aspect by looking at the changes in nucleation and condensation heating.
5. What do you mean by “we zero in on condensation” in Line 499?

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RR by Anonymous Referee #1 (16 Jun 2018)

ED: Publish subject to minor revisions (review by editor) (23 Jun 2018) by Johannes Quaas

AR by Seoung Soo Lee on behalf of the Authors (30 Jul 2018)

ED: Publish as is (15 Aug 2018) by Johannes Quaas

AR by Seoung Soo Lee on behalf of the Authors (21 Aug 2018)