Competition between core and periphery-based processes in warm convective clouds – from invigoration to suppression

Dagan, G.; Koren, I.; Altaratz, O.

doi:https://doi.org/10.5194/acp-15-2749-2015

Articles | Volume 15, issue 5

https://doi.org/10.5194/acp-15-2749-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-15-2749-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 15, issue 5

Research article

|

10 Mar 2015

Research article |

| 10 Mar 2015

Competition between core and periphery-based processes in warm convective clouds – from invigoration to suppression

G. Dagan, I. Koren, and O. Altaratz

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Final revised paper (published on 10 Mar 2015)
Supplement to the final revised paper
Preprint (discussion started on 12 Sep 2014)

Interactive discussion

Status: closed

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

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RC C7734: 'Review of manuscript “Competition between core and periphery-based processes in warm convective clouds – from invigoration to suppression” by Dagan et al', Anonymous Referee #1, 06 Oct 2014
- AC C10291: 'Reply to the referees of "Competition between core and periphery-based processes in warm convective clouds – from invigoration to suppression"', Ilan Koren, 18 Dec 2014
RC C7915: 'Referee Comment', Anonymous Referee #2, 13 Oct 2014
- AC C10292: 'Reply to the referees of "Competition between core and periphery-based processes in warm convective clouds – from invigoration to suppression”', Ilan Koren, 18 Dec 2014

Peer-review completion

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

AR by Svenja Lange on behalf of the Authors (19 Dec 2014) Author's response

ED: Referee Nomination & Report Request started (25 Dec 2014) by Corinna Hoose

RR by Anonymous Referee #1 (11 Jan 2015)

Suggestions for revision or reasons for rejection

The authors made very significant changes on the manuscript and the current manuscript is much improved. The authors addressed most of my comments very well. The authors have done much better job in recognizing and discussing the previous studies and findings on the topic.
I still have two follow-on comments raised by the new figures that I suggested to added.
The first comment is about the aerosol size distribution. First, the figure suggests that the increased aerosols are not likely anthropogenic. From the maritime to the polluted conditions, the significant increase is at 0.1- 1 microns. There is no much increase for particles less than 50 nm. Generally, anthropogenic pollution may enhance aerosol nucleation and increase the nanometer particles significantly. This can be addressed by changing the wording. But most importantly, the different shapes of size distribution among the cases creates more complexity to explain the results, for example, increasing supersaturation at some point would not increase cloud droplet nucleation anymore since aerosol changes are not significant for particles < 50 nm. I am wondering why different aerosol size distributions are used in this study, which imposes another factor (effect of different size distribution) that might impact the results but the authors never discuss this.

The second comment is about cloud updraft vertical velocity. The values are large, especially under conditions of RH1 and RH2. 5- 10 m/s cloud updraft vertical velocity definitely makes deep convective clouds. I understand the study is about idealized tests as the authors argued, but if most of your test cases are not realistic in the nature, then the findings discussed here might not be applicable to the real-world cases.
Judging from the updraft vertical velocity, the 3 0C warm bubble initialization is indeed too strong as I pointed out previously. The authors argued that the random perturbation initialization that I suggested produces many shallow clouds. However, isn’t that the nature of shallow clouds generally? We do not often see just one piece of shallow warm cloud but a cluster of shallow cumuli. The interactions between the shallow cumuli may change the significance of some microphysical processes especially evaporation and entrainment which could lead to different conclusions. This point at least has to be discussed if the authors insist using warm bubble initialization. But I’d suggest using a weaker warm bubble for some cases to produce more realistic shallow warm clouds (with max updraft velocity less than or around 5 m/s which is more appropriate for shallow cloud cases).

Additional minor comments:
(1) About “provides an explanation to the reason models suggest suppression and observations suggest invigoration” – This is just an assumption here. There are many other factors that may contribute to the discrepancies between model and observational results. So, suggest rewording the sentence.

(2) Suggest discussing that the effects (such as lower supersaturation and decreased drag force) resulted from delay of the collision-coalescence process may not be simulated with the bulk parameterization approach.

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RR by Anonymous Referee #2 (15 Jan 2015)

ED: Reconsider after minor revisions (Editor review) (25 Jan 2015) by Corinna Hoose

AR by Ilan Koren on behalf of the Authors (02 Feb 2015) Author's response

ED: Publish subject to technical corrections (20 Feb 2015) by Corinna Hoose

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