Controls on phase composition and ice water content in a convection-permitting model simulation of a tropical mesoscale convective system

Franklin, Charmaine N.; Protat, Alain; Leroy, Delphine; Fontaine, Emmanuel

doi:https://doi.org/10.5194/acp-16-8767-2016

Articles | Volume 16, issue 14

https://doi.org/10.5194/acp-16-8767-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-16-8767-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 16, issue 14

Research article

|

19 Jul 2016

Research article |

| 19 Jul 2016

Controls on phase composition and ice water content in a convection-permitting model simulation of a tropical mesoscale convective system

Charmaine N. Franklin, Alain Protat, Delphine Leroy, and Emmanuel Fontaine

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Final revised paper (published on 19 Jul 2016)
Preprint (discussion started on 19 Jan 2016)

Interactive discussion

Status: closed

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

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RC1: 'Review', Anonymous Referee #1, 18 Feb 2016
- AC1: 'response to reviewer 1', Charmaine Franklin, 26 Apr 2016
RC2: 'Review', Anonymous Referee #2, 07 Mar 2016
- AC2: 'response to reviewer 2', Charmaine Franklin, 26 Apr 2016

Peer-review completion

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

AR by Charmaine Franklin on behalf of the Authors (26 Apr 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (04 May 2016) by Timothy Garrett

RR by Anonymous Referee #1 (19 May 2016)

RR by Anonymous Referee #2 (24 May 2016)

Suggestions for revision or reasons for rejection

Review of "Controls on phase composition and ice water content in a convection permitting model simulation of a tropical mesoscale convective system" by C. N. Franklin, A. Protat, D. Leroy, and E. Fontaine

The manuscript has been improved by major revisions to contents, conclusions and abstract. I would rate this as suitable for publication in ACP after minor changes in two current focus areas, as described below.

1. The authors have removed the discussion of size distribution bi-modality, and placed more focus on mass mean diameter (Dm) with expanded discussion in section 3.2. In discussion of Dm decreasing with increasing ice water content (IWC) during the flight's worth of data they examine here, they report that this is inconsistent with Fridlind et al. (2015), who reported Dm independent of IWC using another data set, but is consistent with Leroy et al. (2015), who used other flights from the same HAIC campaign as examined here. But this misses the central point of Leroy et al. (2015), which is that Dm was found to either increase or decrease with IWC. Leroy et al. select both examples to highlight, showing also that two flights in the same system give median Dm either scarcely changing with IWC or increasing. So in this particular flight the authors find Dm decreasing, which is within the range of previously having been found to increase or decrease during their campaign, which obviously also brackets Dm not changing with IWC, similar to flight 12 of Leroy et al. At a minimum, revisions should be made to clarify that Leroy et al. (2015) also find Dm increasing with IWC. I would also recommend to report whether Leroy examined the same or differing HAIC flights as the particular one examined in this paper.

2. There is increased emphasis on the role of greater turbulent mixing improving simulated stratiform cloud cover (last conclusion #3). The authors state that lack of stratiform rainfall "is likely due to overly strong convection (Figures 2 and 3d) that detrains too high and does not produce enough condensate in the lower stratiform regions as has been shown by Ferrier (1994), Tao et al. (1995) and Morrison et al. (2009)." Ferrier (1994) is a microphysics model description paper, where I could find no such finding. Tao et al. (1995) is a sensitivity study on melting; it does cite Tao et al. (1993) re stronger updrafts detraining less in the conclusions. Would the latter be a better reference? The authors twice cite these same three papers for this finding. Please clarify what you mean to reference from the specific findings from each study; the first reference seems erroneous. Perhaps the conclusions could also point exactly where to view the support for this conclusion, as well; in a search through the document, "stratiform" appears only a handful of times in the current document, one of which refers the reader to discussion in section 3.2.2, which no longer exists.

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ED: Reconsider after major revisions (09 Jun 2016) by Timothy Garrett

AR by Charmaine Franklin on behalf of the Authors (15 Jun 2016) Author's response Manuscript

ED: Publish as is (01 Jul 2016) by Timothy Garrett

Short summary

Simulations of tropical convection are used to investigate the processes that control the phase composition of tropical clouds. It is shown that the growth of ice is less dependent on vertical velocity than is liquid water, with the control on ice water content being the ice sizes and available liquid water. Results show that in the purely ice region of convective updraughts, the buoyancy is controlled by the ice sizes, demonstrating the importance of microphysical processes on convective dynamics.