the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 22 Apr 2024
Glaciation of Mixed-Phase Clouds: Insights from Bulk Model and Bin-Microphysics Large-Eddy Simulation Informed by Laboratory Experiment
Abstract. Mixed-phase clouds affect precipitation and radiation forcing differently from liquid and ice clouds, posing greater challenges to their representation in numerical simulations. Recent laboratory experiments using the Pi Cloud Chamber explored cloud glaciation conditions based on increased injection of ice nucleating particles. In this study, we use two approaches to reproduce the results of the laboratory experiments: a bulk scalar mixing model and large-eddy simulation (LES) with bin microphysics. The first approach assumes a well-mixed domain to provide an efficient assessment of the mean cloud properties for a wide range of conditions. The second approach resolves the energy-carrying turbulence, the particle size distribution, and their spatial distribution to provide more details. These modeling approaches enable a separate and detailed examination of liquid and ice properties, which is challenging in the laboratory. Both approaches demonstrate that, with an increased ice number concentration, the flow and microphysical properties exhibit the same changes in trends. Additionally, both approaches show that the ice integral radius reaches the theoretical glaciation threshold when the cloud is subsaturated with respect to liquid water. The main difference between the results of the two approaches is that the bulk model allows for the complete glaciation of the cloud. However, LES reveals that, in a dynamic system, the cloud is not completely glaciated because liquid water droplets are continuously produced near the warm lower boundary and subsequently mixed into the chamber interior. These results highlight the importance of the ice mass fraction in distinguishing the mixed phase and ice clouds.
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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
(4383 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-2024-1140', Anonymous Referee #1, 09 May 2024
This is the review of the manuscript entitled “Glaciation of Mixed-Phase Clouds: Insights from Bulk Model and Bin-Microphysics Large-Eddy Simulation Informed by Laboratory Experiment” by Wang et al.
This study aims to advance our understanding of mixed-phase clouds using two different modeling approaches to reproduce laboratory experiments conducted in the Pi cloud chamber. Specifically, it is aimed to better understand the theoretically predicted glaciation threshold while the cloud is subsaturated with respect to liquid water. In other words, when is a cloud of mixed-phase type or solely consisting of ice. A bulk scalar mixing model and a large-eddy simulation (LES) with bin microphysics are applied to the Pi chamber studies to examine cloud glaciation. The former model approach allows for complete cloud glaciation while the latter one does not due to the continuous liquid droplet production in the warmer region of the cloud chamber.
This manuscript was an enjoyable read. The chosen approach/methods and execution seem to be sound. The topic fits within the journal’s science areas. I have mostly minor, clarifying, and technical comments and support publication of this work.
Minor comments:
Line 105-110: Somehow equations, variables, and text are not consistent. “N” is not defined. There is no subscript “p”. This is confusing since one reads first the equations; then to rethink subscripts could be cumbersome.
Line 140-142: This is a repetition of line 91.
Line 180: In this equation we have small “n_i”. Is this the same as the capital “N_i” above?
Line 182: Please elaborate what you mean with “s_1,0 is the initial supersaturation of liquid without aerosols”? Is it the supersaturation with respect to liquid water? This would be the case with either/or aerosols? What do you mean with “without aerosols”.
Line 210-213: The first sentence “Without the replenishment from droplet evaporation, the water vapor tends towards saturation over ice more rapidly…” is not wrong but likely confusing. The following sentence clarifies the situation a bit. Did you mean “Without the replenishment from droplet evaporation, the water vapor is more rapidly depleted, thus reaching quicker saturation,…”?
Line 213-215: I do not readily see in Fig. 2h how the integral radius for glaciation predicted by Korolev and Mazin (2003) matches those predicted by the bulk model. Somehow information about N_i has to be given in this discussion? The lines intersect but what does this mean?
Line 249: I cannot see a decrease in the droplet number concentration after 20 minutes in Fig. 4d. After 30 mins there seems to be a brief dip in concentration.
Line 293-296: There is a lot going in this section on which is difficult to follow. Why does the temperature increase in response to the increased ice concentration? With increasing temperature water mixing ratio should increase since e_l increases?
Do you mean a decrease in the supersaturation with respect to liquid water?
“causing the size of the ice crystals to diminish”: If more ice crystal form, supersaturation decreases and resulting ice crystals may be smaller compared to a case with constant supersaturation. However, once ice crystals formed, why should the ice crystal size decrease?
Technical corrections:
Line 105: Missing “respectively”?
Line 124: The subscript for Greek letter Xi: It looks like “1” but should be “l” or “i”?
Line 303: Formatting of units.
Citation: https://doi.org/10.5194/egusphere-2024-1140-RC1 -
RC2: 'Comment on egusphere-2024-1140', Anonymous Referee #2, 16 May 2024
The authors use a bulk model and a LES model with bin microphysics to investigate the glaciation process occurring in the Pi Cloud Chamber. Their experiments are setup according to the laboratory experiments. They found that both the bulk model and the LES model can reproduce the laboratory results, and further found that the bulk model allows complete glaciation while the LES model can always sustain some liquid water. This paper is well written and can be accepted after some minor revisions.
Line 1: “radiation” to “radiative”?
Lines 35-36: The coexistence of ice and liquid does not ensure the occurrence of the WBF process. Please provide further explanations.
Line 78: “near to” to “near”?
Line 112: Please briefly explain the assumptions behind the “mean equilibrium radii”.
Line 182: Please mention that tau_t only consider processes other than microphysics.
Eq. (14): What is phi?
Fig. 3: Please add some 2D cross sections along with the 3D isosurfaces. It is not easy to interpret the 3D isosurfaces, at least for this reviewer.
Line 237: Why excluding the regions within 6.25 cm from the wall?
Line 246: not interquartile.
Fig. 5: Please explain why both (a) and (b) are necessary. What is the dashed line?
Lines 272-274: It is hard to draw the conclusion from Fig. 6, either because further elaboration is required or because a better-designed figure is required.
Citation: https://doi.org/10.5194/egusphere-2024-1140-RC2 -
AC1: 'Comment on egusphere-2024-1140', Aaron Wang, 03 Jul 2024
We sincerely thank the editor, Dr. Greg McFarquhar, and the two anonymous reviewers for the time they have spent evaluating our paper and for their constructive comments that have helped us improve it. We are pleased that the reviewers consider our paper "an enjoyable read" and that "the chosen approach/methods and execution seem to be sound" (reviewer 1). Additionally, we are glad that "this paper is well-written and can be accepted after some minor revisions" (reviewer 2). To better represent our responses with figures, we have attached our point-by-point response as a PDF file.
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2024-1140', Anonymous Referee #1, 09 May 2024
This is the review of the manuscript entitled “Glaciation of Mixed-Phase Clouds: Insights from Bulk Model and Bin-Microphysics Large-Eddy Simulation Informed by Laboratory Experiment” by Wang et al.
This study aims to advance our understanding of mixed-phase clouds using two different modeling approaches to reproduce laboratory experiments conducted in the Pi cloud chamber. Specifically, it is aimed to better understand the theoretically predicted glaciation threshold while the cloud is subsaturated with respect to liquid water. In other words, when is a cloud of mixed-phase type or solely consisting of ice. A bulk scalar mixing model and a large-eddy simulation (LES) with bin microphysics are applied to the Pi chamber studies to examine cloud glaciation. The former model approach allows for complete cloud glaciation while the latter one does not due to the continuous liquid droplet production in the warmer region of the cloud chamber.
This manuscript was an enjoyable read. The chosen approach/methods and execution seem to be sound. The topic fits within the journal’s science areas. I have mostly minor, clarifying, and technical comments and support publication of this work.
Minor comments:
Line 105-110: Somehow equations, variables, and text are not consistent. “N” is not defined. There is no subscript “p”. This is confusing since one reads first the equations; then to rethink subscripts could be cumbersome.
Line 140-142: This is a repetition of line 91.
Line 180: In this equation we have small “n_i”. Is this the same as the capital “N_i” above?
Line 182: Please elaborate what you mean with “s_1,0 is the initial supersaturation of liquid without aerosols”? Is it the supersaturation with respect to liquid water? This would be the case with either/or aerosols? What do you mean with “without aerosols”.
Line 210-213: The first sentence “Without the replenishment from droplet evaporation, the water vapor tends towards saturation over ice more rapidly…” is not wrong but likely confusing. The following sentence clarifies the situation a bit. Did you mean “Without the replenishment from droplet evaporation, the water vapor is more rapidly depleted, thus reaching quicker saturation,…”?
Line 213-215: I do not readily see in Fig. 2h how the integral radius for glaciation predicted by Korolev and Mazin (2003) matches those predicted by the bulk model. Somehow information about N_i has to be given in this discussion? The lines intersect but what does this mean?
Line 249: I cannot see a decrease in the droplet number concentration after 20 minutes in Fig. 4d. After 30 mins there seems to be a brief dip in concentration.
Line 293-296: There is a lot going in this section on which is difficult to follow. Why does the temperature increase in response to the increased ice concentration? With increasing temperature water mixing ratio should increase since e_l increases?
Do you mean a decrease in the supersaturation with respect to liquid water?
“causing the size of the ice crystals to diminish”: If more ice crystal form, supersaturation decreases and resulting ice crystals may be smaller compared to a case with constant supersaturation. However, once ice crystals formed, why should the ice crystal size decrease?
Technical corrections:
Line 105: Missing “respectively”?
Line 124: The subscript for Greek letter Xi: It looks like “1” but should be “l” or “i”?
Line 303: Formatting of units.
Citation: https://doi.org/10.5194/egusphere-2024-1140-RC1 -
RC2: 'Comment on egusphere-2024-1140', Anonymous Referee #2, 16 May 2024
The authors use a bulk model and a LES model with bin microphysics to investigate the glaciation process occurring in the Pi Cloud Chamber. Their experiments are setup according to the laboratory experiments. They found that both the bulk model and the LES model can reproduce the laboratory results, and further found that the bulk model allows complete glaciation while the LES model can always sustain some liquid water. This paper is well written and can be accepted after some minor revisions.
Line 1: “radiation” to “radiative”?
Lines 35-36: The coexistence of ice and liquid does not ensure the occurrence of the WBF process. Please provide further explanations.
Line 78: “near to” to “near”?
Line 112: Please briefly explain the assumptions behind the “mean equilibrium radii”.
Line 182: Please mention that tau_t only consider processes other than microphysics.
Eq. (14): What is phi?
Fig. 3: Please add some 2D cross sections along with the 3D isosurfaces. It is not easy to interpret the 3D isosurfaces, at least for this reviewer.
Line 237: Why excluding the regions within 6.25 cm from the wall?
Line 246: not interquartile.
Fig. 5: Please explain why both (a) and (b) are necessary. What is the dashed line?
Lines 272-274: It is hard to draw the conclusion from Fig. 6, either because further elaboration is required or because a better-designed figure is required.
Citation: https://doi.org/10.5194/egusphere-2024-1140-RC2 -
AC1: 'Comment on egusphere-2024-1140', Aaron Wang, 03 Jul 2024
We sincerely thank the editor, Dr. Greg McFarquhar, and the two anonymous reviewers for the time they have spent evaluating our paper and for their constructive comments that have helped us improve it. We are pleased that the reviewers consider our paper "an enjoyable read" and that "the chosen approach/methods and execution seem to be sound" (reviewer 1). Additionally, we are glad that "this paper is well-written and can be accepted after some minor revisions" (reviewer 2). To better represent our responses with figures, we have attached our point-by-point response as a PDF file.
Peer review completion
Journal article(s) based on this preprint
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Steve Krueger
Sisi Chen
Mikhail Ovchinnikov
Will Cantrell
Raymond A. Shaw
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(4383 KB) - Metadata XML