Further evidence for CCN aerosol concentrations determining the height of warm rain and ice initiation in convective clouds    over the Amazon basin

Braga, Ramon Campos; Rosenfeld, Daniel; Weigel, Ralf; Jurkat, Tina; Andreae, Meinrat O.; Wendisch, Manfred; Pöschl, Ulrich; Voigt, Christiane; Mahnke, Christoph; Borrmann, Stephan; Albrecht, Rachel I.; Molleker, Sergej; Vila, Daniel A.; Machado, Luiz A. T.; Grulich, Lucas

doi:https://doi.org/10.5194/acp-17-14433-2017

Articles | Volume 17, issue 23

https://doi.org/10.5194/acp-17-14433-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue:

https://doi.org/10.5194/acp-17-14433-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 17, issue 23

Research article

|

05 Dec 2017

Research article |

| 05 Dec 2017

Further evidence for CCN aerosol concentrations determining the height of warm rain and ice initiation in convective clouds over the Amazon basin

Ramon Campos Braga, Daniel Rosenfeld, Ralf Weigel, Tina Jurkat, Meinrat O. Andreae, Manfred Wendisch, Ulrich Pöschl, Christiane Voigt, Christoph Mahnke, Stephan Borrmann, Rachel I. Albrecht, Sergej Molleker, Daniel A. Vila, Luiz A. T. Machado, and Lucas Grulich

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Final revised paper (published on 05 Dec 2017)
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Preprint (discussion started on 09 Feb 2017)
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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: 'Referee Report', Anonymous Referee #1, 03 Apr 2017
- AC1: 'Comments for referee number 1', Ramon Braga, 07 Apr 2017
RC2: 'Referee Comments', Anonymous Referee #2, 25 Apr 2017
- AC2: 'Comments for referee number 2', Ramon Braga, 28 May 2017
RC3: 'Manuscript Review - Reviewer 3', Darrel Baumgardner, 27 Apr 2017
- AC3: 'Comments for referee number 3 - Darrel Baumgardner', Ramon Braga, 28 May 2017

Peer-review completion

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

AR by Ramon Braga on behalf of the Authors (29 May 2017) Manuscript

ED: Publish as is (08 Jun 2017) by Andrew Heymsfield

AR by Ramon Braga on behalf of the Authors (09 Jun 2017)

ED: Referee Nomination & Report Request started (24 Jul 2017) by Andrew Heymsfield

RR by Anonymous Referee #2 (02 Aug 2017)

Suggestions for revision or reasons for rejection

Review of revised paper.

The authors have not satisfactorily addressed several of the very
reasonable and serious points made by the referees and editor. As far as
I can tell, the revised manuscript has changed very little. Many of the
problems listed in the first review remain in this manuscript.

These include:

1. The main result of the paper is to produce a relationship between the
height of the first measurement of drizzle drops and the estimated
number of cloud drops at cloud base (Fig 17). The problem with the
approach and the resulting relationship is the lack of attention to
detail. The authors have offered very little discussion of the
limitations of the observations and processes which can break or
increase the error in the simple relationship. Ultra-giant aerosols,
enhancement of collision and coalescence due to turbulence and increased
supersaturation due to entrainment and mixing will all potentially
weaken the relationship.

2. There are no figures in the paper to show that the measurements were
made in the main updraft near cloud top to avoid observing raindrops
formed at higher levels and falling in the downdrafts around the cloud
edges. What is the evidence that the cloud top was not higher at an
earlier time? In fact there are no figures showing the dynamical
structure of the clouds.

3. There is the persistent argument that the almost constant value of
the effective radius is evidence of inhomogeneous mixing. If
inhomogeneous mixing had occurred, there would likely be an increase in
supersaturation and hence in the size of the largest drops as well as
activation of CCN from the drops evaporated due to the mixing.
Importantly, the raindrops would most likely form at a lower level than
in a cloud region containing the number of cloud drops activated at
cloud base and moved in an adiabatic parcel. Similar arguments can be
made for turbulent enhancement.

4. As the authors admit themselves, they have insufficient information
to examine ice initiation in these clouds.

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RR by Anonymous Referee #4 (02 Aug 2017)

RR by Darrel Baumgardner (07 Aug 2017)

ED: Reject (13 Aug 2017) by Andrew Heymsfield

ED: Reconsider after major revisions (21 Aug 2017) by Andrew Heymsfield

AR by Ramon Braga on behalf of the Authors (29 Sep 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (06 Oct 2017) by Andrew Heymsfield

RR by Darrel Baumgardner (15 Oct 2017)

RR by Anonymous Referee #2 (21 Oct 2017)

RR by Ismail Gultepe (23 Oct 2017)

ED: Publish subject to minor revisions (review by editor) (24 Oct 2017) by Andrew Heymsfield

AR by Ramon Braga on behalf of the Authors (27 Oct 2017) Author's response Manuscript

ED: Publish as is (03 Nov 2017) by Andrew Heymsfield

AR by Ramon Braga on behalf of the Authors (03 Nov 2017)