the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 06 Jun 2023
Fragmentation of ice particles: laboratory experiments on graupel-graupel and graupel-snowflake collisions
Abstract. Until now, the processes involved in secondary ice production which generate high concentrations of ice crystals in clouds have been poorly understood. However, collisions that involve rimed ice particles or crystal aggregates have the potential to effectively produce secondary ice from their fragmentation. Unfortunately, there have only been a few laboratory studies on ice-ice collision, resulting in an inaccurate representation of this process in microphysical schemes. To address this issue, experiments were conducted at the Wind tunnel laboratory of the Johannes Gutenberg University, Mainz on graupel- graupel and graupel-snowflake collisions under still air conditions at -15 °C and over water saturation. All fragments resulting from graupel-graupel collisions were collected and investigated by means of a digital optical microscope, while fragments from graupel-snowflake collisions were observed and recorded instantly after collision using a holographic instrument. From these experiments, distributions were obtained for fragment sizes, cross sectional areas and aspect ratios. The results showed a higher number of fragments at lower kinetic energy compared to those presented in the literature. 150 to 600 fragments were observed for graupel-graupel collisions, and 70 to 500 fragments for graupel-snowflake collisions between 10−7 and 10−5 J. Parametrizations for fragment size distributions are provided with a mode at 75 µm for graupel-graupel collisions and at 400 µm for graupel-snowflake collisions. These results can be used to improve the representation of ice collision breakup in microphysical schemes.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
(19277 KB)
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2023-1074', Anonymous Referee #1, 26 Jun 2023
This paper reports on a laboratory study of graupel-graupel and graupel-snow aggregate collisions. The numbers of fragments and the size distributions produced are presented.
The authors do a good job of describing their setup and show some compelling results. It is very good to see these new observations coming out that can eventually be implemented in numerical cloud models, and the authors have provided representations of the fragment particle size distributions as well and fragment number-collision energy relationships.This is hopefully the beginning of a suite of experiments to explore the behaviour of these collisions for a range of graupel and aggregate sizes under different temperature and saturation conditions, that will be reported in future papers.
I think the paper is publishable. I have some very minor comments.
Main:
I would suggest that highly dendritic growth on a graupel particle seen in fig 5b would not be observed in the real atmosphere. It would be difficult to obtain saturations above water saturation (~14% at -14C). At water saturation there would be droplets that would continue the riming.For a realistic graupel with vapour grown surface ice i think that a superaturation with respect to ice but below water saturation is required.
It would be good to caveat the results for the dendrite-covered_graupel vs graupel collisions.
Perhaps it would be possible to include the bare graupel-graupel collision results that were alluded to?
Minor:
line 215: What was the 'glue' used for sticking? Were the crystals just brought together at ice saturation or slightly above? How long were the crystals allowed to sinter for? I imagine there will be sensitivity to this. In the results the production process for the aggregates is mentioned, but perhaps it is worth saying that this is something that could be explored more systematically in the future?line 302: Fig 12 i think needs a caveat to mention that these results are likely to be an upper bound because of the very high saturations the graupel were exposed to. Much more than is likely in a real cloud.
line 344: For fig. 14 graupel-snow collisions it may be appropriate to just suggest a mean and range (e.g. 200 splinters ranging from 100-400 to capture 95% of measurements. Hopefully, later experiments will provide enough data to parameterise the degree of separation effect. For models some average would likely be necessary to use.
line 350: The size distribution of fragments is very welcome. For implementation in a model this would likely need to be scaled by the size of the snowparticle being collided with.
In the first instance the use of 10mm snow aggregates could be used to scale the x axis (at least as an extra axis)?line 354: Only 16 distributions in here so difficult to draw too many conclusions from the individual modes - apart from the mode at 50um being the size of the monomers.
line 368: This 50um mode is just the size of the monomers used to construct the aggregate, so unless Vardiman constructed their snow in the same way there is unlikely to have been a mode in those observations?
line 401: Agreed. It would be great to see results for a range of graupel sizes and snow sizes to cover the phase space required in a numerical cloud model.
Citation: https://doi.org/10.5194/egusphere-2023-1074-RC1 -
AC1: 'Reply on RC1', Miklós Szakáll, 01 Sep 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-AC1-supplement.pdf
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AC1: 'Reply on RC1', Miklós Szakáll, 01 Sep 2023
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RC2: 'Comment on egusphere-2023-1074', Anonymous Referee #2, 27 Jun 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-RC2-supplement.pdf
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AC2: 'Reply on RC2', Miklós Szakáll, 01 Sep 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-AC2-supplement.pdf
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AC2: 'Reply on RC2', Miklós Szakáll, 01 Sep 2023
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RC3: 'Comment on egusphere-2023-1074', Alexei Korolev, 21 Jul 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-RC3-supplement.pdf
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AC3: 'Reply on RC3', Miklós Szakáll, 01 Sep 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-AC3-supplement.pdf
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AC3: 'Reply on RC3', Miklós Szakáll, 01 Sep 2023
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2023-1074', Anonymous Referee #1, 26 Jun 2023
This paper reports on a laboratory study of graupel-graupel and graupel-snow aggregate collisions. The numbers of fragments and the size distributions produced are presented.
The authors do a good job of describing their setup and show some compelling results. It is very good to see these new observations coming out that can eventually be implemented in numerical cloud models, and the authors have provided representations of the fragment particle size distributions as well and fragment number-collision energy relationships.This is hopefully the beginning of a suite of experiments to explore the behaviour of these collisions for a range of graupel and aggregate sizes under different temperature and saturation conditions, that will be reported in future papers.
I think the paper is publishable. I have some very minor comments.
Main:
I would suggest that highly dendritic growth on a graupel particle seen in fig 5b would not be observed in the real atmosphere. It would be difficult to obtain saturations above water saturation (~14% at -14C). At water saturation there would be droplets that would continue the riming.For a realistic graupel with vapour grown surface ice i think that a superaturation with respect to ice but below water saturation is required.
It would be good to caveat the results for the dendrite-covered_graupel vs graupel collisions.
Perhaps it would be possible to include the bare graupel-graupel collision results that were alluded to?
Minor:
line 215: What was the 'glue' used for sticking? Were the crystals just brought together at ice saturation or slightly above? How long were the crystals allowed to sinter for? I imagine there will be sensitivity to this. In the results the production process for the aggregates is mentioned, but perhaps it is worth saying that this is something that could be explored more systematically in the future?line 302: Fig 12 i think needs a caveat to mention that these results are likely to be an upper bound because of the very high saturations the graupel were exposed to. Much more than is likely in a real cloud.
line 344: For fig. 14 graupel-snow collisions it may be appropriate to just suggest a mean and range (e.g. 200 splinters ranging from 100-400 to capture 95% of measurements. Hopefully, later experiments will provide enough data to parameterise the degree of separation effect. For models some average would likely be necessary to use.
line 350: The size distribution of fragments is very welcome. For implementation in a model this would likely need to be scaled by the size of the snowparticle being collided with.
In the first instance the use of 10mm snow aggregates could be used to scale the x axis (at least as an extra axis)?line 354: Only 16 distributions in here so difficult to draw too many conclusions from the individual modes - apart from the mode at 50um being the size of the monomers.
line 368: This 50um mode is just the size of the monomers used to construct the aggregate, so unless Vardiman constructed their snow in the same way there is unlikely to have been a mode in those observations?
line 401: Agreed. It would be great to see results for a range of graupel sizes and snow sizes to cover the phase space required in a numerical cloud model.
Citation: https://doi.org/10.5194/egusphere-2023-1074-RC1 -
AC1: 'Reply on RC1', Miklós Szakáll, 01 Sep 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-AC1-supplement.pdf
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AC1: 'Reply on RC1', Miklós Szakáll, 01 Sep 2023
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RC2: 'Comment on egusphere-2023-1074', Anonymous Referee #2, 27 Jun 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-RC2-supplement.pdf
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AC2: 'Reply on RC2', Miklós Szakáll, 01 Sep 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-AC2-supplement.pdf
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AC2: 'Reply on RC2', Miklós Szakáll, 01 Sep 2023
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RC3: 'Comment on egusphere-2023-1074', Alexei Korolev, 21 Jul 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-RC3-supplement.pdf
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AC3: 'Reply on RC3', Miklós Szakáll, 01 Sep 2023
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1074/egusphere-2023-1074-AC3-supplement.pdf
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AC3: 'Reply on RC3', Miklós Szakáll, 01 Sep 2023
Peer review completion
Journal article(s) based on this preprint
Data sets
Experimental data for "Fragmentation of ice particles: laboratory experiments on graupel-graupel and graupel-snowflake collisions" Pierre Grzegorczyk, Sudha Yadav, Florian Zander, Alexander Theis, Subir Kumar Mitra, and Miklós Szakáll https://doi.org/10.5281/zenodo.7877368
Video supplement
Collision between two graupel particles in a fall tube Pierre Grzegorczyk, Alexander Theis, Mitra, Subir Kumar Mitra, and Miklós Szakáll https://av.tib.eu/media/62064
Collision between a snowflake and a graupel in a fall tube - edge collision Pierre Grzegorczyk, Alexander Theis, Mitra, Subir Kumar Mitra, and Miklós Szakáll https://av.tib.eu/media/62065
Collision between a snowflake and a graupel in a fall tube - central collision Pierre Grzegorczyk, Alexander Theis, Mitra, Subir Kumar Mitra, and Miklós Szakáll https://doi.org/10.5446/62066
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Cited
Pierre Grzegorczyk
Sudha Yadav
Florian Zanger
Alexander Theis
Subir K. Mitra
Stephan Borrmann
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(19277 KB) - Metadata XML