Damaging viscous-plastic sea ice

Savard, Antoine; Tremblay, Bruno

doi:https://doi.org/10.5194/egusphere-2023-1354

Preprints

https://doi.org/10.5194/egusphere-2023-1354

Preprints

03 Aug 2023

| 03 Aug 2023

Damaging viscous-plastic sea ice

Antoine Savard and Bruno Tremblay

Abstract. We implement a damage parametrization in the standard viscous-plastic sea ice model to disentangle its effect from model physics (visco-elastic or elasto-brittle vs. visco-plastic) on its ability to reproduce observed scaling laws of deformation. To this end, we compare scaling properties and multifractality of simulated divergence and shear strain rate (as proposed in SIREx1), with those derived from the RADARSAT Geophysical Processor System (RGPS). Results show that including a damage parametrization in the standard viscous-plastic model increases the spatial, but decreases temporal localization of simulated Linear Kinematic Features, and brings all spatial deformation rate statistics in line with observations from RGPS without the need to increase the mechanical shear strength of sea ice as recently proposed for lower resolution viscous-plastic sea ice models. In fact, including damage an healing timescale of t_h = 30 days and an increased mechanical strength unveil multifractal behavior that does not fit the theory. Therefore, a damage parametrization is a powerful tuning knob affecting the deformation statistics.

Received: 20 Jun 2023 – Discussion started: 03 Aug 2023

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.

Download & links

Preprint (PDF, 4114 KB)

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.
Preprint (4114 KB)

Download & links

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Journal article(s) based on this preprint

30 Apr 2024

On the sensitivity of sea ice deformation statistics to plastic damage

Antoine Savard and Bruno Tremblay

The Cryosphere, 18, 2017–2034, https://doi.org/10.5194/tc-18-2017-2024,https://doi.org/10.5194/tc-18-2017-2024, 2024

Short summary

Antoine Savard and Bruno Tremblay

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2023-1354', Jérôme Weiss, 12 Sep 2023

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1354/egusphere-2023-1354-RC1-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2023-1354-RC1
- AC3: 'Reply on RC1', Antoine Savard, 14 Dec 2023
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1354/egusphere-2023-1354-AC3-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2023-1354-AC3
RC2:
'Comment on egusphere-2023-1354', Anonymous Referee #2, 25 Oct 2023

This paper is a useful contribution because the authors have demonstrated the multifractal behavior the VP and a VP model modified to include damage can have (or in fact not have). While the model does not match observations there is discussion of how the model behaves that could help future investigators improve models of sea ice deformation. What is lacking is often a physical interpretation of the model behavior. While relationships are described mathematically, such as the differences in scaling exponents or departure from expected multifractal behavior, no context as to why this might be is given. Perhaps this is not possible to determine, however it would be useful insight.

Overall I feel this contribution is valuable and should be published. Though I would caution readers to consider if multifractals are the best metric to validate simulated deformation or distinguish models. There are places where the authors can strenghten their argument as to why it is important to reproduce observed scaling behavior for sea ice deformation or linear kinematic features. The contribution of this paper in describing the model behavior with the mathematical language of multifractals is helpful in the conversation.

General comments

The deformation of sea ice is shown to be coupled in space and time, such that the scaling relationship in each varies depending on the sampling in the other. This means that when comparing a model with observations you have to account for this time or space sampling difference. How do you ensure that you are comparing scaling relationships for the same time or space sampling in the model and observations?

It is a useful comment that even ad-hoc parameterization of heterogeneity in ice strength could improve representation of sea ice deformation. This jives with my personal experience where if I solve the VP model to full plastic equilibrium it is not possible to simulate LKFs unless you seed variability in ice strength randomly. Which is about as simple a parameterization as one can make! In the introduction a damage parameterization is introduced, and in the discussion this is compared to other parameterizations used in other models. It might help the reader to give a little information about how the parameterizations differ up front and why you choose to develop your own.

Specific Comments

Abstract line 8: Grammatical error "an"

Line 14: Is "ilks" a good word to use here?
This is a stylistic comment that you can take or leave: I found the first paragraph of the introduction did not really guide me to what the content of the paper would be about. In general I would suggest the introduction could be more focused.

Line 24: Typical floe sizes range from meters to 10s of kilometers. So saying floe size is 10km is factually incorrect. It is correct to mention that the data you are working with has this lower resolution, but incorrect to call it floe size.

Line 30: "complex laws" This is overly general. I encourage you to be more specific. This is also where you could point out that unlike turbulence in water or air, the scaling relationships for sea ice deformation are coupled in space and time. There is also large differences in scaling exponents found for different years and seasons, so it would be good to comment on if you accounting for this or just using values found for a particular time period or region.

Line 34: Why should a model of Arctic sea ice simulate LKFs?

Line 51: Missing full stop.

Line 163: Sea ice can diverge and weaken (through reduced area) in the VP model even when LKFs are not present.

Line 205-210: I am curious, when you are creating a run with 10 random years how do you ensure there are not unphysical jumps in the wind forcing between years? Does this matter, given the spin up of ice drift is relatively fast compared to the wind speed change.

Line 316: "soup-like" is a weird choice of word here. Also is there a missing label by the "2".

Line 320: "simulation" => "simulations"

Line 331: I believe the decay is log-linear not linear.

Figure 3: It is not clear where the observations in the black line are from. Where do you describe the observations in the paper and how you calculate the deformation. Are the distributions for model and observations from the same time and region? It is only apparent later in the paper that you are only considering data from January 2002 (line 538). Which makes me think you need to improve details in your methodology.

Line 378: "morally" is a weird word choice here.

I could not check code and data availably because links were not provided.

Citation: https://doi.org/10.5194/egusphere-2023-1354-RC2
- AC2: 'Reply on RC2', Antoine Savard, 14 Dec 2023
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1354/egusphere-2023-1354-AC2-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2023-1354-AC2
EC1:
'Comment on egusphere-2023-1354 by acting Editor', Daniel Feltham, 16 Nov 2023

The manuscript proposes a simple, but ad hoc and poorly physically justified, approach to modification of the ice strength in a popular sea ice rheology scheme. The purpose of this is to create a low-computational cost way to better simulate some of the scaling properties of deformation. It is interesting, though not especially surprising (as the authors note), that this enables capture of some of these scaling relations with such a simple treatment.
I am sympathy with the general approach taken and there is much in this paper that is of value. The ad hoc approach is obviously not ideal and raises important concerns over appropriate choice of timescales, but then the rheology that is being modified is also exceedingly ad hoc and has been in use for over 40 years. Clearly the authors are aiming for a no-cost, practical approach that can be easily implemented into existing modelling architectures.
Nonetheless, one of the reviewers raised very important points that must be taken into account. Particularly damage refers to reduction of the elasticity, not plastic ice strength. As an Editor, I view it as my job to prevent the propagation of terms that are likely to cause confusion and are at odds with existing and mature bodies of work. As a result, I will not accept this paper if the word damage is used in its current form.
If the authors wish to proceed with revisions then careful account should be taken of all the comments by the reviewers, with particularly full responses given if a recommendation is not followed. But I reiterate that an alternative language must be found to express the reduction in ice strength and the word damage removed from the paper and title. The obvious term that springs to my mind is plastic weakening, which is what I believe it actually is.

Citation: https://doi.org/10.5194/egusphere-2023-1354-EC1
- AC1: 'Reply on EC1', Antoine Savard, 14 Dec 2023
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1354/egusphere-2023-1354-AC1-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2023-1354-AC1

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2023-1354', Jérôme Weiss, 12 Sep 2023

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1354/egusphere-2023-1354-RC1-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2023-1354-RC1
- AC3: 'Reply on RC1', Antoine Savard, 14 Dec 2023
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1354/egusphere-2023-1354-AC3-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2023-1354-AC3
RC2:
'Comment on egusphere-2023-1354', Anonymous Referee #2, 25 Oct 2023

This paper is a useful contribution because the authors have demonstrated the multifractal behavior the VP and a VP model modified to include damage can have (or in fact not have). While the model does not match observations there is discussion of how the model behaves that could help future investigators improve models of sea ice deformation. What is lacking is often a physical interpretation of the model behavior. While relationships are described mathematically, such as the differences in scaling exponents or departure from expected multifractal behavior, no context as to why this might be is given. Perhaps this is not possible to determine, however it would be useful insight.

Overall I feel this contribution is valuable and should be published. Though I would caution readers to consider if multifractals are the best metric to validate simulated deformation or distinguish models. There are places where the authors can strenghten their argument as to why it is important to reproduce observed scaling behavior for sea ice deformation or linear kinematic features. The contribution of this paper in describing the model behavior with the mathematical language of multifractals is helpful in the conversation.

General comments

The deformation of sea ice is shown to be coupled in space and time, such that the scaling relationship in each varies depending on the sampling in the other. This means that when comparing a model with observations you have to account for this time or space sampling difference. How do you ensure that you are comparing scaling relationships for the same time or space sampling in the model and observations?

It is a useful comment that even ad-hoc parameterization of heterogeneity in ice strength could improve representation of sea ice deformation. This jives with my personal experience where if I solve the VP model to full plastic equilibrium it is not possible to simulate LKFs unless you seed variability in ice strength randomly. Which is about as simple a parameterization as one can make! In the introduction a damage parameterization is introduced, and in the discussion this is compared to other parameterizations used in other models. It might help the reader to give a little information about how the parameterizations differ up front and why you choose to develop your own.

Specific Comments

Abstract line 8: Grammatical error "an"

Line 14: Is "ilks" a good word to use here?
This is a stylistic comment that you can take or leave: I found the first paragraph of the introduction did not really guide me to what the content of the paper would be about. In general I would suggest the introduction could be more focused.

Line 24: Typical floe sizes range from meters to 10s of kilometers. So saying floe size is 10km is factually incorrect. It is correct to mention that the data you are working with has this lower resolution, but incorrect to call it floe size.

Line 30: "complex laws" This is overly general. I encourage you to be more specific. This is also where you could point out that unlike turbulence in water or air, the scaling relationships for sea ice deformation are coupled in space and time. There is also large differences in scaling exponents found for different years and seasons, so it would be good to comment on if you accounting for this or just using values found for a particular time period or region.

Line 34: Why should a model of Arctic sea ice simulate LKFs?

Line 51: Missing full stop.

Line 163: Sea ice can diverge and weaken (through reduced area) in the VP model even when LKFs are not present.

Line 205-210: I am curious, when you are creating a run with 10 random years how do you ensure there are not unphysical jumps in the wind forcing between years? Does this matter, given the spin up of ice drift is relatively fast compared to the wind speed change.

Line 316: "soup-like" is a weird choice of word here. Also is there a missing label by the "2".

Line 320: "simulation" => "simulations"

Line 331: I believe the decay is log-linear not linear.

Figure 3: It is not clear where the observations in the black line are from. Where do you describe the observations in the paper and how you calculate the deformation. Are the distributions for model and observations from the same time and region? It is only apparent later in the paper that you are only considering data from January 2002 (line 538). Which makes me think you need to improve details in your methodology.

Line 378: "morally" is a weird word choice here.

I could not check code and data availably because links were not provided.

Citation: https://doi.org/10.5194/egusphere-2023-1354-RC2
- AC2: 'Reply on RC2', Antoine Savard, 14 Dec 2023
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1354/egusphere-2023-1354-AC2-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2023-1354-AC2
EC1:
'Comment on egusphere-2023-1354 by acting Editor', Daniel Feltham, 16 Nov 2023

The manuscript proposes a simple, but ad hoc and poorly physically justified, approach to modification of the ice strength in a popular sea ice rheology scheme. The purpose of this is to create a low-computational cost way to better simulate some of the scaling properties of deformation. It is interesting, though not especially surprising (as the authors note), that this enables capture of some of these scaling relations with such a simple treatment.
I am sympathy with the general approach taken and there is much in this paper that is of value. The ad hoc approach is obviously not ideal and raises important concerns over appropriate choice of timescales, but then the rheology that is being modified is also exceedingly ad hoc and has been in use for over 40 years. Clearly the authors are aiming for a no-cost, practical approach that can be easily implemented into existing modelling architectures.
Nonetheless, one of the reviewers raised very important points that must be taken into account. Particularly damage refers to reduction of the elasticity, not plastic ice strength. As an Editor, I view it as my job to prevent the propagation of terms that are likely to cause confusion and are at odds with existing and mature bodies of work. As a result, I will not accept this paper if the word damage is used in its current form.
If the authors wish to proceed with revisions then careful account should be taken of all the comments by the reviewers, with particularly full responses given if a recommendation is not followed. But I reiterate that an alternative language must be found to express the reduction in ice strength and the word damage removed from the paper and title. The obvious term that springs to my mind is plastic weakening, which is what I believe it actually is.

Citation: https://doi.org/10.5194/egusphere-2023-1354-EC1
- AC1: 'Reply on EC1', Antoine Savard, 14 Dec 2023
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1354/egusphere-2023-1354-AC1-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2023-1354-AC1

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

ED: Reconsider after major revisions (further review by editor and referees) (19 Dec 2023) by Daniel Feltham

AR by Antoine Savard on behalf of the Authors (17 Jan 2024) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (31 Jan 2024) by Daniel Feltham

RR by Anonymous Referee #2 (23 Feb 2024)

Suggestions for revision or reasons for rejection

Dear Antoine and Bruno,

While I disagree that using scaling information for validation of sea ice kinematics in models is a sensible tool, I feel your paper adds insight into how different models reproduce the statistical and scaling features that have been observed. For that reason, this is worth publishing. I still have reservations about encouraging the use of these metrics for evaluating models. Given the observations are not as clear cut and Marsan et al. (2004) suggests, I am not entirely convinced sea ice deformation has a well behaved multi-fractal nature. Perhaps the results in your models showing this, point towards quasi brittle systems not behaving as cleanly as Marsan et al. (2004) suggests. Also, what sets the scaling exponents is an interaction between forcing and dissipation that can be adjusted in multiple ways in models (and nature), which makes the use of this as a metric by itself for model tuning problematic. However in attempting to model the localization of deformation, this paper does add useful information to that conversation.

I would like to refer to reviewer 1 as to whether the discussion of the different damage parameterizations in EB and VP, and that they are not equivelent, is adequately addressed. Echoing the editor, we do not want to propagate misuse of standard terms.

A specific comment

In the introduction you state that models need to be both put into the same numerical framework to allow inter comparison. Do you actually achieve this? All your results are for the VP model, and not EB. So perhaps you need to reframe this to not mislead the reader you are doing this. But rather that you are focussed on the behavior of your modified VP model.

In reading the paper I found some consistent gramatical issues, that I suggest you proof read to make sure you catch throughout the manuscript. I point out below copy edit needs I found.

Abstract line 4: (as proposed in SIREx1) is not needed, and also SIREx should be expanded if this is kept.

line 8 "damage with a healing"

line 9 "unveils"

line 10 it might help to specify "sea ice deformation statitics" ... but your choice if you want to point the reader back to your not being general here. Sea ice is only mentioned in the first sentence of the abstract, and it is inferred that you continue to talk about this.

line 11 The first sentence is hanging.

First paragraph of the introduction. One could argue that this whole paragraph is irrelevent to the topic of the paper. It is an interesting paragraph, and probably should be saved for the lead authors thesis. Though I would suggest adding some clarification to what you are describing.

Line 30 you use "sea-ice" and "sea ice" as an adjective in different parts of the text. Maintain a consistency with this, choose one convention.

Line 43 not sure the use of hyphens here is good.

Line 56 "Elasto-Brittle (EB) and modification thereof (MEB and BBM)"

Line 58 "... larger deformations occur along fault lines ..."

Line 62 check if deformation is singular or plural. This should be checked for correctness throughout.

Line 365 and other places. You have a liking of starting a sentence with "Interestingly". Excessive use of this becomes uninteresting and distracts from your use of this construct to imbibe some interest in the reader.

Lines 442-444: This sentence is mangled and hard to follow.

Line 468-469 remove "-- also called intermittency --"

Line 506 "... RGPS observations than that of ..."

Code and data availability section. Citations for code and ice velocity model output not provided.

Hide

RR by Jérôme Weiss (28 Feb 2024)

ED: Publish subject to minor revisions (review by editor) (28 Feb 2024) by Daniel Feltham

AR by Antoine Savard on behalf of the Authors (11 Mar 2024) Author's response Author's tracked changes Manuscript

ED: Publish as is (12 Mar 2024) by Daniel Feltham

AR by Antoine Savard on behalf of the Authors (18 Mar 2024) Manuscript

Journal article(s) based on this preprint

30 Apr 2024

On the sensitivity of sea ice deformation statistics to plastic damage

Antoine Savard and Bruno Tremblay

The Cryosphere, 18, 2017–2034, https://doi.org/10.5194/tc-18-2017-2024,https://doi.org/10.5194/tc-18-2017-2024, 2024

Short summary

Antoine Savard and Bruno Tremblay

Viewed

Total article views: 452 (including HTML, PDF, and XML)

HTML	PDF	XML	Total	BibTeX	EndNote
315	107	30	452	16	17

HTML: 315
PDF: 107
XML: 30
Total: 452
BibTeX: 16
EndNote: 17

Views and downloads (calculated since 03 Aug 2023)

Month	HTML	PDF	XML	Total
Aug 2023	92	25	4	121
Sep 2023	44	15	3	62
Oct 2023	31	11	4	46
Nov 2023	13	5	2	20
Dec 2023	38	11	7	56
Jan 2024	28	8	3	39
Feb 2024	31	14	1	46
Mar 2024	21	11	1	33
Apr 2024	17	7	5	29
May 2024	0
Jun 2024	0
Jul 2024	0
Aug 2024	0
Sep 2024	0

Cumulative views and downloads (calculated since 03 Aug 2023)

Month	HTML	PDF	XML	Total
Aug 2023	92	25	4	121
Sep 2023	44	15	3	62
Oct 2023	31	11	4	46
Nov 2023	13	5	2	20
Dec 2023	38	11	7	56
Jan 2024	28	8	3	39
Feb 2024	31	14	1	46
Mar 2024	21	11	1	33
Apr 2024	17	7	5	29
May 2024	0
Jun 2024	0
Jul 2024	0
Aug 2024	0
Sep 2024	0

Viewed (geographical distribution)

Total article views: 442 (including HTML, PDF, and XML) Thereof 442 with geography defined and 0 with unknown origin.

Country	#	Views	%

Cited

Latest update: 18 Sep 2024

Download

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Preprint (4114 KB)
Metadata XML

Short summary

We include a suitable damage parametrization in the standard viscous-plastic (VP) sea ice model to disentangle its effect from model physics (visco-elastic or elasto-brittle vs. visco-plastic) on its ability to reproduce observed scaling laws of deformation. This study shows that including a damage parametrization in the VP model improves its performance in simulating the statistical behavior of fracture patterns. Therefore, a damage parametrization is a powerful tuning knob.


Total:	0
HTML:	0
PDF:	0
XML:	0

Damaging viscous-plastic sea ice

Journal article(s) based on this preprint

Interactive discussion

Interactive discussion

Peer review completion

Suggestions for revision or reasons for rejection

Suggestions for revision or reasons for rejection

Journal article(s) based on this preprint

Viewed

Viewed (geographical distribution)

Cited

1 citations as recorded by crossref.