Not all feldspars are equal: a survey of ice nucleating properties
across the feldspar group of minerals

Harrison, Alexander D.; Whale, Thomas F.; Carpenter, Michael A.; Holden, Mark A.; Neve, Lesley; O'Sullivan, Daniel; Vergara Temprado, Jesus; Murray, Benjamin J.

doi:https://doi.org/10.5194/acp-16-10927-2016

Articles | Volume 16, issue 17

https://doi.org/10.5194/acp-16-10927-2016

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

https://doi.org/10.5194/acp-16-10927-2016

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

Articles | Volume 16, issue 17

Research article

|

05 Sep 2016

Research article |

| 05 Sep 2016

Not all feldspars are equal: a survey of ice nucleating properties across the feldspar group of minerals

Alexander D. Harrison, Thomas F. Whale, Michael A. Carpenter, Mark A. Holden, Lesley Neve, Daniel O'Sullivan, Jesus Vergara Temprado, and Benjamin J. Murray

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Final revised paper (published on 05 Sep 2016)
Preprint (discussion started on 19 Feb 2016)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review on “Not all feldspar is equal: a survey of ice nucleating properties across the feldspar group of minerals” by Harrison and Whale et al.', Anonymous Referee #1, 22 Mar 2016
RC2: 'Review of Harrison et al.', Anonymous Referee #2, 22 Mar 2016
AC1: 'Response to Referee #1', T.F. Whale, 20 Jun 2016
AC2: 'Response to referee #2', T.F. Whale, 20 Jun 2016

Peer-review completion

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

AR by T.F. Whale on behalf of the Authors (27 Jun 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (28 Jun 2016) by Alex Huffman

RR by Anonymous Referee #1 (11 Jul 2016)

Suggestions for revision or reasons for rejection

Second review on “Not all feldspar is equal: a survey of ice nucleating properties across the feldspar group of minerals” by Harrison and Whale et al.

This study contributes to a better understanding of the ice nucleation ability of feldspars. The manuscript has been improved after the incorporation of suggestions from the first reviews, but not all comments had been addressed. I recommend publication on ACP after the following comments and suggestion will have been addressed.

General comment

In the new version of the manuscript, the statement that two types of hyperactive feldspar exist which are able to induce freezing at high temperature where usually biological particles, in particular proteins, are presumed to act as ice nucleating particles is weakened (p.11 l.18). But only the influence of biological contaminations is discussed. However, the fact that the sample are only heated to 100°C for 15 minutes do not exclude other heat-resistant species to act as INP at this high temperature. For example in Fukuta 1966 a whole list of organic ice nucleating particles is given showing onset temperatures of -1°C or -1.5°C. I do not doubt that “hyperactive” feldspars exist but I am not convinced that enough test had been made to constrict all possibilities. This still needs to be done and discussed in the manuscript. Further the statements in the abstract (p.1 l27,29) and conclusions (p.17 l.22, 23, 24, 30) have to be weakened, too.

Specific comments

p.2 l.4-6:
The causal association is not clear. The sentence must be reformulated.

p.7 l.21:
When the cold stage chamber is flowed with dry nitrogen during the experiment. Do you observe effects from droplet evaporation?

p.8 l.7:
The meaning of the term “active site” is still not introduced in the paper.

p.10, l21-22:
This statement might be true, but applies only for the analysed weight concentration range. Add “for the analysed weight concentration range”.

p.12 l.2:
I prefer that the authors use always the same word for the same meaning, otherwise the reader thinks about if there is a difference or not. That means the terms “site”, “active site”, etc. should be unified in the whole manuscript!

p.12 l.4:
The term “activation temperatures” is not introduced. What does it mean?

p.17 l.1:
What does “microliter regime” means? This is not physically meaningful. It would be better to give the mass concentration range, number of particles or available surface area, but not the droplet size.

Technical corrections

p.7 l.30:
Delete “heterogeneous”.

p.7 l.26:
“higher” instead of “greater”

p.11 l.5; p.11 l.29; p.18 l.26:
“higher” instead of “warmer”

p.11 l.19; p.17 l.21:
“high” instead of “warm”

p.11 l.28:
“lower” instead of “colder”

p.12 l.18:
Delete unnecessary information: “the time between successive runs”.

p.17 l.20 and l.25:
Delete “generic”.

p.17 l.23 and l.24:
Use consistent notation for “hyperactive”.

Fig. 4:
The Figure has a bad resolution.

Bibliography

Fukuta, N. (1966) Experimental studies of organic ice nuclei. Journal of the Atmospheric Sciences, 23, 191-&, doi: 10.1175/1520-0469(1966)023<0191:esooin>2.0.co;2.

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RR by Anonymous Referee #2 (11 Jul 2016)

ED: Reconsider after minor revisions (Editor review) (14 Jul 2016) by Alex Huffman

AR by T.F. Whale on behalf of the Authors (22 Jul 2016) Author's response Manuscript

ED: Publish as is (25 Jul 2016) by Alex Huffman

AR by T.F. Whale on behalf of the Authors (03 Aug 2016)

Short summary

Mineral dust particles are known to act as effective ice nucleating particles in the atmosphere and to play a role in the glaciation of mixed phase clouds. We have measured the ice nucleation activity of 15 different feldspar samples using a droplet freezing experiment and shown that alkali feldspars nucleate ice much more efficiently than plagioclase feldspars. We have also shown that certain "hyper-active" alkali feldspars nucleate ice very efficiently compared to typical alkali feldspars.