This paper presents a novel sea ice model that represents the mixed phase between grease ice and consolidated ice floes, including both dynamic and thermodynamic components. The work investigates the response of this model to idealized wave forcing for a sea ice configuration derived from SAR imagery. Simpler configurations are also considered as sensitivity experiments. The key diagnostics are the mean viscosity and local strain rate as a function of wave properties and ice floe concentration relative to grease ice.

This work represents a useful advance in modelling sea ice within marginal ice zones and its response to wave forcing. My specific comments are listed below.

Eq. 6: Does the vertical component of wave velocity play a role in these simulations? The rheology seems to be described for a 2-D simulation only (section 2.1.2).

L138: What does ‘apical plane’ mean?

Table 1: Can you describe how these values were chosen?

L238: Why can we expect a higher growth rate for frazil ice? Is it because it is thinner than the floes?

Fig 2: Why is there not much happening in the first and last parts of the curves in Fig 2a and the first part of Fig 2b?

Fig 2: What are the radiative and snow forcings used to obtain these plots? And what is used for the simulations presented in the results section?

L306-307: How was the thickness of ice determined in the SAR image?

L307: The minimum threshold for what exactly?

L312: If I understand correctly, the sub-domains are defined for diagnosis purpose only. Mentioning them here caused some confusion for me, as not much information was provided about what they represented. One solution could be to not mention them here, but describe them later in the context of Fig 8.

L317: ‘that gradually increase in thickness’. This could be misinterpreted as an increase in time. I suggest rephrasing.

Fig 5: Could you please explain the motivation behind the configurations shown in panels b-e, including the wiggles in panel e?

L338-339: ‘The viscosity is locally affected by the propagating wave, since the rheology of the grease ice and ice floes is described as a function of thickness (Eq. (15) and (18)).’ I don't understand how the first part of the sentence follows from the second part. Could you please explain in more detail?

L361-364: ‘Figure 8(e) and (f) illustrate the relative difference in shear viscosity between the highest and lowest wave periods. The viscosity values in the case with waves from the west are significantly higher than those from the south, indicating a greater response to wave periods.’ I don’t understand how this indicates a greater response to wave periods. Could you clarify?

L369-370: The north-south orientation of what?

L370: Can this linear relationship be derived analytically? If so, this may be another useful output of the paper regarding parameterization of these effects in climate models.

L376-377: ‘Based on the linear relationship presented in Fig. 9, we assume that the model resolves the smaller scales of the heterogeneous field, allowing us to extract properties at larger scales.’ How does the linear relationship allow you to make this assumption?

L380-381: ‘Therefore, we considered subdomain groups of increasing size from 1 to 6, with the latter corresponding to the full domain (see Fig. 8(a))’. This is not entirely clear to me. What are the sizes of these groups and how are they chosen spatially? What units does ‘1 to 6’ have in the above sentence and what does it represent exactly? Perhaps a diagram would help?

L382: ‘The results are presented in Table 3, showing a strong scale invariance from 800 m up to 5 km. The 800 m scale is already sufficient to capture the heterogeneity of the ice cover, and variations in ice type patterns do not affect the mechanical response at the larger scales up to 5 km.’ Where do the numbers 500 m and 5 km come from? I am guessing they result from the size of each group, but this is hard to infer from just Table 3. Also, for clarity, please state explicitly what is invariant with scale.

L497: ‘in the dynamic model by 3% in t = 24h’. Should it be ‘at t = 24h’?

L507-508: ‘degree of heterogeneity’ is a bit ambiguous to me. I think ice floe percentage relative to grease ice would be clearer.

Before I begin, I would like to apologize to the Authors and to the Editors for being so much late with this review.

***

In their manuscript „WIce-FOAM 1.0: Coupled dynamic and thermodynamic modelling…”, Rutger Marquart and coauthors describe an OpenFOAM-based sea ice model designed to study the effects of sea ice type (“ice floes” versus “grease ice”), spatial orientation and arrangement of ice floes, and wave forcing (wave length and direction) on the net (domain-averaged) viscosity of the ice. The model considers two ice types with two different, prescribed rheology models, at ice concentration of 100%. The dynamic part of the model is coupled with a thermodynamic model, so that nonlinear coupling between ice dynamics and thermodynamics can be studied.

The manuscript is very well and clearly written, the figures illustrate well the topics discussed and the results obtained. The assumptions and limitations of the model and of the simulations are clearly stated. I find the results very interesting and relevant, as they might contribute to better understanding of sea ice rheology in the marginal ice zone, and thus to better parameterizations for sea ice models. In my opinion, after some rather minor corrections, the manuscript is worth publishing in GMD.

My comments and questions are as follows:

1. Line 90: “As a result, interactions between ice floes are represented as continuous, churning contact of varying intensity rather than brief, forceful impacts. This justifies the exclusion of ice floe failure and fracture.”
   
   It justifies the exclusion of failure and fracture due to floe-floe collisions, but not fracture in general, due to, e.g., ice convergence, shear deformation or bending of floes on waves. Maybe it’s worth formulating more precisely?
2. Lines 101-103: I’d consider moving the references from line 101 to 103, just before equation (3). Equation (2) is quite obvious and doesn’t require references.
3. Line 138: “apical plane”?
4. Lines 193-194: “For the ice floes, the one-dimensional thermodynamic model in the z-direction, developed by Tedesco et al. (2009), is applied to OpenFOAM cells associated with ice floes to simulate thermodynamic variations in snow and ice thickness.” Does it mean that the ice floes in cells associated with grease ice do not grow thermodynamically? And vice versa, how is the growth of grease ice treated in cells classified as ice floes?
   
   Earlier, line 87 states that “cells are classified according to the predominant ice type - either ice floes or grease ice”. But what does it really mean? And, first of all, why is this classification necessary? Is the information on the surface area fraction covered with a given ice type not enough?
5. Line 254: “we can interpolate the thermodynamic model”. Is “interpolate” the right word here? What exactly is interpolated?
6. Lines 338-339: “The viscosity is locally affected by the propagating wave, since the rheology of the grease ice and ice floes is described as a function of thickness.” Is it really the thickness that’s responsible for the observed differences in viscosity? And not the different form of the two rheology models? In other words, if the thickness of ice floes and grease ice was the same, would viscosity remain unaffected?
7. Line 369: “the intercept at 0% represents the viscosity of grease ice” – which seems to be zero in Fig. 9. I think it requires a comment.
8. Lines 369-370: “The north-south orientation describes a linear relationship (see the equation in Fig. 9).” This sentence is unclear. Orientation of what? A relationship between what?
9. Lines 376-377: “Based on the linear relationship presented in Fig. 9, we assume that the model resolves the smaller scales of the heterogeneous field, allowing us to extract properties at larger scales.” Please explain why/how exactly the obtained relationship justifies this assumption.
10. I find the results presented in Figs. 13 and 14 quite remarkable. The contribution of the bridge connecting the two floes to the total model surface area is very minor, well below 1%, presumably closer to 0.1% (as far as I can estimate it from the plots in Fig. 13), but its influence on the area-averaged viscosity, seen in Fig. 14, is at the level of 1%. To me, this suggests that the net viscosity is indeed very sensitive to the orientation of tiny (in terms of surface area fraction) “ice elements”, presumably much more so than Fig. 9 may suggest – as, in the “real” case, different contributions from many elements with different orientations cancel out. (All this might be related to the discussion around line 510 in the manuscript?). This would mean that in situations with strong anisotropy of the ice cover very small changes e.g. in wave propagation direction may lead to significant changes in net viscosity.
    
    Another interesting thing in Fig. 14 is that the panel (b) is qualitatively different from the other three: In this case, the viscosity increases with wave period – as it does in the cases shown in Fig. 7, but unlike in those in Fig. 14 a,c,d. What is the explanation for this behavior? I think this fact should be commented upon.     
11. Lines 486-488: “We also observed changes in the magnitude and oscillatory behaviour of the mean shear viscosity that are indicative of resonance at smaller scales that can be propagated to the kilometre scales.” Is there a possibility that the oscillations are related to the model setup (e.g., the periodic domain and the fact that the wavelength is adjusted to the domain size) and/or numerics (numerical schemes used etc.)?
12. Line 497: “in t = 24h”. Meaning after 24h?