Observational estimates of detrainment and entrainment in non-precipitating shallow cumulus

Norgren, M. S.; Small, J. D.; Jonsson, H. H.; Chuang, P. Y.

doi:https://doi.org/10.5194/acp-16-21-2016

Articles | Volume 16, issue 1

https://doi.org/10.5194/acp-16-21-2016

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

https://doi.org/10.5194/acp-16-21-2016

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

Articles | Volume 16, issue 1

Research article

|

14 Jan 2016

Research article |

| 14 Jan 2016

Observational estimates of detrainment and entrainment in non-precipitating shallow cumulus

M. S. Norgren, J. D. Small, H. H. Jonsson, and P. Y. Chuang

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Final revised paper (published on 14 Jan 2016)
Preprint (discussion started on 26 Aug 2014)

Interactive discussion

Status: closed

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

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- Supplement

RC C7797: 'Review', Anonymous Referee #1, 08 Oct 2014
- AC C13226: 'Reply to both reviewers (one file)', Patrick Chuang, 27 May 2015
RC C10197: 'Review on “Observational estimates of detrainment and entrainment in non-precipitating shallow cumulus clouds” by M. S. Norgren, J. D. Small, H. H. Jonsson and P. Y. Chuang', Anonymous Referee #2, 16 Dec 2014
- AC C13227: 'Reply to both reviewers (single file)', Patrick Chuang, 27 May 2015

Peer-review completion

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

AR by Patrick Chuang on behalf of the Authors (27 May 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (13 Jul 2015) by Geraint Vaughan

RR by Anonymous Referee #2 (04 Aug 2015)

RR by Anonymous Referee #1 (07 Sep 2015)

Suggestions for revision or reasons for rejection

Although the authors have provided thorough responses to most of the
reviewers' comments and suitable changes have been made to the
manuscript, a few critical points remain.

1. Wetting of the temperature probe. The authors do not demonstrate that
the temperature probe did not get wet in the project GoMACCS. Saying
there's no evidence of jumps at the base of Stratocumulus clouds is not
proof that it does not get wet when going into a cumulus cloud which has
greater liquid water content. I asked to see simple time series of
liquid water content, updraft and temperature. Several examples should
be shown and a thorough response given.

2. Below cloud air. The air below cloud base can be substantially warmer
than the air in the surrounding environment. As the authors mention
there can be a difference of at least 2 kJ/kg, which is signficant in
the calculation of sa (e.g Fig 3).

3. Detrainment layers. The study of Raymond et al (1991) discussed the
issues concerning detrainment layers -- i.e. they occur at particular
altitudes according to the environmental thermodynamic conditions in
different days. E.g. cloud top near an inversion. It is more likely to
miss that layer with an aircraft that is penetrating clouds than to
encounter it! The conclusions (and abstract) should be qualified.

The method should ideally eventually (not in this paper) be compared
with model results and with results from an aircraft performing boxes
around the cloud.

4. Precipitation. While it is likely that the aerosol concentration was
high on most days and it is also likely that the high concentration
prevented the production of precipitation, the authors should present
the criterion used to exclude clouds with precipitation size drops
present.

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ED: Reconsider after major revisions (10 Sep 2015) by Geraint Vaughan

AR by Patrick Chuang on behalf of the Authors (03 Nov 2015) Author's response Manuscript

ED: Reconsider after minor revisions (Editor review) (17 Nov 2015) by Geraint Vaughan

AR by Patrick Chuang on behalf of the Authors (27 Nov 2015) Author's response Manuscript

ED: Publish as is (03 Dec 2015) by Geraint Vaughan

AR by Patrick Chuang on behalf of the Authors (11 Dec 2015)

Short summary

Clouds transport air from near the surface to higher altitudes. However, the amount of air transported in this way is poorly understood. In this study, measurements from aircraft of small clouds over Texas show that the amount is limited to the volume of the visible cloud and not more. This means that these clouds are not very effective at transporting pollution and moisture to upper reaches of the atmosphere, which in turn affects their redistribution and wider impact.