Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations

Vergara-Temprado, Jesús; Murray, Benjamin J.; Wilson, Theodore W.; O'Sullivan, Daniel; Browse, Jo; Pringle, Kirsty J.; Ardon-Dryer, Karin; Bertram, Allan K.; Burrows, Susannah M.; Ceburnis, Darius; DeMott, Paul J.; Mason, Ryan H.; O'Dowd, Colin D.; Rinaldi, Matteo; Carslaw, Ken S.

doi:https://doi.org/10.5194/acp-17-3637-2017

Articles | Volume 17, issue 5

https://doi.org/10.5194/acp-17-3637-2017

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

Special issue:

BACCHUS – Impact of Biogenic versus Anthropogenic emissions...

https://doi.org/10.5194/acp-17-3637-2017

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

Articles | Volume 17, issue 5

Research article

|

15 Mar 2017

Research article |

| 15 Mar 2017

Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations

Jesús Vergara-Temprado, Benjamin J. Murray, Theodore W. Wilson, Daniel O'Sullivan, Jo Browse, Kirsty J. Pringle, Karin Ardon-Dryer, Allan K. Bertram, Susannah M. Burrows, Darius Ceburnis, Paul J. DeMott, Ryan H. Mason, Colin D. O'Dowd, Matteo Rinaldi, and Ken S. Carslaw

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Final revised paper (published on 15 Mar 2017)
Preprint (discussion started on 21 Sep 2016)

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Status: closed

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

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RC1: 'Review of “Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations”', Anonymous Referee #1, 19 Oct 2016
- AC2: 'Response to first comment', Jesús Vergara Temprado, 21 Dec 2016
RC2: 'Review "Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations" by Vergara-Temprado et al. 2016', Anonymous Referee #2, 29 Oct 2016
- AC3: 'Response to second comment', Jesús Vergara Temprado, 21 Dec 2016
AC1: 'Version with tracked changed after the reviewers comments', Jesús Vergara Temprado, 21 Dec 2016
AC4: 'Version without the changes tracked', Jesús Vergara Temprado, 21 Dec 2016

Peer-review completion

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

AR by Jesús Vergara Temprado on behalf of the Authors (13 Jan 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (20 Jan 2017) by Corinna Hoose

RR by Anonymous Referee #2 (06 Feb 2017)

Suggestions for revision or reasons for rejection

Comments:
- You stated in your abstract that "Many modelling studies use parameterizations for heterogeneous ice nucleation and cloud ice
processes that do not account for this difference because they were developed based on INP measurements made predominantly in terrestrial environments." You reacted on the argument that "If a scheme was developed for terrestrial sources and does not account for marine sources, the INP concentration represented in the model would be different for marine and terrestrial sources as well (it would be smaller above marine regions as shown by the field observations).” by stating that the parameterization schemes you referred to are aerosol-species-independend. In that case your argumentation is true. However, in the abstract (and also partly in the introduction) you write it so generally that it does not become clear like that. You either have to add the specific parameterization schemes that you refer to or you have at least to state that most parameterization schemes do not take the aerosol species (and thus indirectly the sources) into account. There are existing parameterization schemes used that take the aerosol composition into account and also only based on terrestrial sources show lower INP over the ocean.

- I think it is missleading how you formulated your statement that the particle-to-particle variability is better represented in the ns-scheme. It is true that the ns-approach takes into account the spectrum of a species in activating ice, but still in the end you use an average density of active sites. At one specific temperature you will get a fixed fraction of particles that nucleate- this number is the average number of particles in your total particle population that freeze under the given temperature. If you would want to explicitely account for (a variable) particle to particle variation you would need to use a ns-distribution for each temperature for each species.

- It is not true that in the case of using classical nucleation theory with a single contact angle time dependence is the main factor that drives nucleation, also in this case it is temperature. Time is less important compared to temperature (also in CNT).
- Page 3, line 24: Change "The temperature dependent number of active sites..." to "The temperature dependent number of active sites per surface area ..."

- Table 1: You could use the three different results coming from different temperature ranges (without *, *, **) to analyse how the different parameterizations react on extrapolation. The Niemand et al. scheme seems to have the trouble predicting the INP at low temperatures, the perfomance improves in the case the cold temperature values are left away. The marine and k-feldspar scheme on the other hand seems to especially capture the high temperature range well, since the performance goes down in the case of leaving the high temperature values.

- Looking at Fig. 8: It could have been interesting to see the same for a k-feldspar only parameterization scheme (without marine contribution).

- Page 10, line 23: "through all the mixed-phase range of temperatures" sounds a bit strange. You mean "through all the temperature range of mixed-phase clouds"?

- Fig. 3: The example of color scale for the temperatures in mixed-phase cloud still does not make sense or does not add any value to the Figure. You either have to use the colors somewhere in the Figure, or leave them away.

- Caption Fig. 3: ambient should be subscript.

- Caption Fig. 4: 600hpa should be 600 hPa.

- In Fig. 4 you write that the upper panel shows the INP conc. at 600 hPa at -20°C and the lower panel the INP conc. at 600 hPa at ambient temperature. If one looks at the Arctic, the INP conc. is higher in the lower panel compared to the upper panel. That means the temperature has to be lower in the lower panel and thus in the Arctic the local ambient temperature is lower than -20°C? Is that the case or is something in the caption/figure wrong?

- I understand why you chose a temperature of -15°C and the surface concentrations to calculate INP ambient and compare it to the measurements. However, that should be critically commented in the paper since the real (ambient) IN conc. would be different from what you call INP ambient.

- Figure 6: You could rename the axis label 1/m³ to 10^(-3) 1/l. Then you would keep it consistent and the numbers would still be readable in the plot.

- Page 12, line 5/6: Provide a citation for studies about a statement about extrapolating singular parameterizations.

- Page 23, line 11: Add INP -> "In addition, more INP measurements...".

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ED: Reconsider after minor revisions (Editor review) (15 Feb 2017) by Corinna Hoose

AR by Jesús Vergara Temprado on behalf of the Authors (16 Feb 2017) Author's response Manuscript

ED: Publish as is (01 Mar 2017) by Corinna Hoose

AR by Jesús Vergara Temprado on behalf of the Authors (01 Mar 2017)

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Short summary

We quantify the importance in the atmosphere of different aerosol components to contribute to global ice-nucleating particles concentrations (INPs). The aim is to improve the way atmospheric cloud-ice processes are represented in climate models so they will be able to make better predictions in the future. We found that a kind of dust (K-feldspar), together with marine organic aerosols, can help to improve the representation of INPs and explain most of their observations.